EVOLUTION & GENETIC NEWS, Gaia Church
|
EVOLUTION
& GENETIC
NEWS '06 &7
.
|
Click here for a page on CURRENT EXTINCTION NEWS). (formerly mixed in this page, as, after all, extinction is a major part of evolution.) Prehistoric extinctions are still on this page.
Skip down to "EVO-NEWS".
.
EVOLUTION NEWS, 2007
.
.
Dec 21, 07: The world's tallest animal, the giraffe, may actually be several species, a study has found. Currently, giraffes are considered to represent a single species classified into multiple subspecies.
. . The study shows geographic variation in hair coat color is evident across the giraffe's range in sub-Saharan Africa, suggesting reproductive isolation. "Using molecular techniques, we found that giraffes can be classified into six groups that are reproductively isolated and not interbreeding." But in zoos, they do.
. . These results are interesting as giraffes are highly mobile animals. They frequently range over several hundred square km and are capable of long distance movements of some 50-300km, which means different populations are likely to meet. Mr Brown added: "There are no rivers or forests to prevent breeding, but some evolutionary process is keeping the two groups reproductively separated."
. . Over the past decade, there has been a 30% drop in giraffe numbers, with total numbers under 100,000.
Dec 21, 07: Most modern day groups of beetles have been around since the dinosaurs. It was thought that today's beetle lineages evolved alongside the arrival of flowering plants, some 140 million years ago. A new report has pre-dated their appearance by 110 million years, back to the Jurassic period.
. . Very soon after beetles originated, they evolved into the lines that persist today, researchers say. There are more than 300,000 species of beetles on Earth, accounting for a quarter of all living things.
Dec 20, 07: About 470 million years ago, back when our ancestors were jawless fishes and the land was ruled by insects, Earth was pounded by a series of enormous meteorites. The traces of that hammering still survive today in ancient rocks in southern Sweden and central China, where scientists have found exotic mineral grains found only in meteorites.
. . By measuring the amount of the grains in the rocks, the scientists calculated the rate of meteorite impacts jumped by a factor of 100 around 470 million years ago. A number of the impacts were big enough to leave 20-mile craters. The energy unleashed was 10 million times greater than the energy in the nuclear bomb dropped on Hiroshima.
. . At the same time, scientists have also been putting together a chronology of fossils from the same time, known as the Ordovician Period. They're recording when species first emerged in the fossil record, and when they disappeared as they became extinct. And this week in the journal Nature Geoscience, the scientists report that the impacts coincided with a drastic change in the world's biodiversity. The diversity of life took a sharp climb right after the meteorites started falling.
. . Scientists say the discovery is quite unusual. Nature Geoscience's press release declares, "These results are surprising as meteorite impacts are often more commonly associated with mass extinctions." But actually, aside from the Cretaceous impact, no other case for impact-triggered mass extinctions has strong support today.
. . Meanwhile, geochemists and paleontologists are finding evidence that points to other culprits for the mass extinctions. Global warming appears to be behind many of the biggest. Volcanoes can unleash vast amounts of CO2, and heat-trapping methane can rise up from the sea floor. There's some evidence that these past episodes of global warming triggered a chain reaction of destruction, from the acidification of the oceans to the destruction of the ozone layer. It looks as if our planet can wreak its own destruction without the help of planetisimals (or even people).
. . How could meteorites drive up the diversity of life? The researchers aren't sure, but they suggest that the impacts may have disturbed old ecosystems, creating a new space in which new species could evolve.
. . It's particularly intriguing to compare the number of species in crater lakes to other lakes of the same size. Crater lakes are often much more diverse. It's possible the planetisimals or comets that scoop out the craters also fertilize them with minerals and other nutrients, supporting more species.
. . This fertilization from space may have made life itself possible on Earth. Four billion years ago, comets and planetisimals delivered water, organic molecules, and other raw materials necessary for life. Some of the early craters may have even served as natural beakers that synthesized new chemicals essential for life. Not every impact was so benign on the early Earth; judging from the craters still preserved on Luna, the biggest ones may have boiled off the oceans. But some researchers have also speculated that microbes could have been lofted into space, where they could have survived on meteorites, or perhaps on other planets, before reseeding Earth.
Dec 20, 07: Some seals and dolphins can hold their breath underwater for a cheek-popping hour or more without passing out from lack of oxygen. The secret to the superhero animal feat is elevated levels of special oxygen-carrying proteins found in their brains, a new study reveals. But the research leaves puzzles.
. . Scientists have long wondered why marine mammals, such as dolphins, whales, Weddell seals and sea otters, are so tolerant of such low oxygen conditions. The simplest explanation had been that they evolved adaptations to boost oxygen delivery to the brain. But studies have shown that the oxygen levels in their blood vessels plummeted within minutes of dipping beneath the water's surface.
. . Williams and her colleagues focused on two newly discovered proteins called neuroglobin and cytoglobin. They are similar to hemoglobin, an iron-containing molecule that carries oxygen in blood and circulates throughout the body and brain, but neuroglobins and cytoglobins (grouped together as brain globins) reside in brain tissues.
. . The scientists compared the amounts of hemoglobin and the brain globins in 16 mammal species, including land animals such as a bobcat and a mountain lion, shallow swimmers such as the bottlenose dolphin and California sea lion, and deep divers such as the pilot whale and Risso's dolphin.
. . The results were not clear-cut. On average, the brains of marine mammals had more hemoglobin and brain globins than those of land animals, suggesting it's these proteins that keep the divers alive and alert during deep dives.
. . The shallow-swimming and highly active dolphins, sea lions and sea otters had higher amounts of the brain globins than did the deep-diving whales. Williams suggests that the agile swimmers need to shuttle oxygen quickly to the brain and so they rely on the brain globins rather than the hemoglobin. The more hemoglobin in the blood, the more viscous the blood becomes, making transport to the brain slower.
Dec 20, 07: [tool-users!!] It's scary being a little, tasty squirrel, but some species of the rodents have come up with an intimidating camouflage --snake smells. California ground squirrels and rock squirrels chew up rattlesnake skin and smear it on their fur to mask their scent, a team at the U of California Davis reported. The scent probably helps to mask the squirrel's own scent, especially when the animals are asleep in their burrows.
Dec 19, 07: The gigantic ocean-dwelling whale may have evolved from a land animal the size of a small raccoon, new research suggests. What might be the missing evolutionary link between whales and land animals is an odd animal that looks like a long-tailed deer without antlers or an overgrown long-legged rat, fossils indicate.
. . The creature is called Indohyus, and recently unearthed fossils reveal some crucial evolutionary similarities between it and water-dwelling cetaceans, such as whales, dolphins and porpoises. For years, the hippo has been the leading candidate for the closest land relative because of its similar DNA and whale-like features.
. . "As a zoo animal, it looks nothing like a whale", Thewissen said. But, he added, when it comes to anatomical features, the Indohyus "is quite strikingly like one. The earliest whales didn't look like whales at all", Thewissen said. "It looked like a cross between a pig and a dog." They lost their legs and ability to walk on land about 40 million years ago.
. . He created a composite skeleton of a 48 million-year-old creature. The key finding connecting Indohyus to the whale is its thickened ear bone, something only seen in cetaceans. An examination of its teeth showed that the land-dwelling creature spent lots of time in the water and may have fed there, like hippos and whales. Also, the specific positioning and shape of certain molars connects Indohyus to the earliest whales, which are about 50 million years old, Thewissen said.
Dec 18, 07: The offspring of expensive stallions owe their success more to nurture than nature, a study suggests.
Dec 18, 07: Researchers in a remote Indonesian jungle have discovered a giant rat that is about five times the size of a typical city rat and a tiny possum, scientists said.
Dec 18, 07: A college education doesn't give you much of an edge over a monkey when it comes to doing some basic arithmetic, according to a study.
. . In a rapid fire test of mental addition, monkeys performed almost as well as college students. The macaques got their sums right 76% of the time, while the students got the correct answer 94% of the time. It also suggests that basic arithmetic may be part of our shared evolutionary past.
. . Both the monkeys and the students took longer to make a choice and made more mistakes when the two choice boxes were close in number. "We call this the ratio effect", said Cantlon. "What's remarkable is that both species suffered from the ratio effect at virtually the same rate."
Dec 12, 07: Scientists think they have figured out why pregnant women don't lose their balance and topple over despite ever-growing weight up front. Evolution provided them with slight differences from men in their lower backs and hip joints, allowing them to adjust their center of gravity, new research shows.
. . This elegant engineering is seen only in female humans and our immediate ancestors who walked on two feet, but not in chimps and apes, according to a study.
. . Harvard anthropology researcher Katherine Whitcomb found two physical differences in male and female backs that until now had gone unnoticed: One lower lumbar vertebra is wedged-shaped in women and more square in men; and a key hip joint is 14 percent larger in women than men when body size is taken into account.
. . The researchers did engineering tests that show how those slight changes allow women to carry the additional and growing load without toppling over —-and typically without disabling back pain.
. . When the researchers looked back at fossil records of human ancestors, including the oldest spines that go back 2 million years to our predecessor, Australopithecus, they found a male without the lower-back changes and a female with them.
Dec 12, 07: A graduate student has identified the remains of one of the planet’s largest meat-eating dinosaurs ever found. Steve Brusatte, a paleobiologist at the U of Bristol in England, determined fossils discovered during a 1997 Nigerian expedition belong to a new breed of dinosaur called Carcharodontosaurus iguidensis.
. . The upright-walking creature grinned with a mouth full of banana-sized teeth, stood taller than a double-decker bus and weighed more than two standard-sized cars. Evidence of the 95-million-year-old theropod has been extremely hard to come by.
. . "This has implications for the world today in which temperatures and sea level are rising", he said. "By studying these sorts of ecosystems that we can hope to understand how our modern world may change."
. . C. iguidensis weighed in at 3.2 tons and extended more than 14 meters, but was not the largest terrestrial meat-eating dinosaur ever discovered. That title belongs to Spinosaurus aegyptiacus -—an 8-ton, 17-meter long behemoth with a sail-like back.
Dec 12, 07: Flowering plant species are as diverse as they are numerous. Turns out, these bloomers went through an evolutionary "Big Bang" of sorts some 130 million years ago, a brief era of explosive floral diversification at a time when dinosaurs walked the Earth. The origin of flowering plants called angiosperms has long baffled scientists.
. . Two new papers show a stunning diversification occurred within a period of 5 million years just after the plants first appeared on the scene and gave rise to today's five major lineages of flowering plants. "Flowering plants today comprise around 400,000 species."
Dec 12, 07: Scientists searching for fossils high in the Andes mountains in Chile have unearthed the remains of a tank-like mammal related to armadillos that grazed 18 million years ago. "It looks different than almost anything out on the landscape today."
. . It was a primitive relative of a line of heavily armored mammals that culminated in the massive, impregnable Gyptodon, a two-ton, 3-meter-long beast covered in armored plates and a spiky tail. Gyptodon, the size of a Volkswagen Beetle, died out 10,000 years ago.
. . This creature, Parapropalaehoplophorus, had similar traits, but was much smaller, at 90 kg and 2-1/2 feet. It originated in South America and later entered North America after the two continents joined 3 million years ago.
. . The scientists think the area has been thrust upward since this mammalian mini-tank lived there 18 million years ago. It was, they think, an open savannah about 3,000 feet above sea level, dotted with trees and home to grazing mammals.
. . Any predator would have had a hard time making a meal of Parapropalaehoplophorus or any of the glyptodonts. They were the most heavily armored mammals ever to live on Earth --similar in their armor to the spiky, formidable dinosaur Ankylosaurus that lived 50 million years earlier. Parapropalaehoplophorus was covered by a shell of immovable armored plates, different from the hinged rows of plates on today's armadillos.
Dec 11, 07: Nobody knows for sure how life formed in the first place, but the thinking is that first you had to have the building blocks -—organic compounds containing carbon and hydrogen. A new study finds these building blocks could have formed very early in the history of Mars. The research says nothing about whether there is life on Mars, but it does indicate that the raw material for life should be easy to drum up there.
. . First, scientists re-examined the well-studied and highly controversial meteorite known as Allan Hills 84001. It's a rock from Mars that long ago was flung from that planet by an impact and fortuitously landed on Earth. It's been said by some scientists to contain direct signs of life on Mars, but that conclusion has been hotly debated for years.
. . Second, scientists looked at terrestrial rocks from Svalbard, Norway. The Svalbard rocks were created by volcanic eruptions in a freezing Arctic climate about a million years ago. The conditions are thought to be similar to ancient Mars.
. . "Organic material occurs within tiny spheres of carbonate minerals in both the Martian and Earth rocks", said study leader Andrew Steele. "We found that the organic material is closely associated with the iron oxide mineral magnetite, which is the key to understanding how these compounds formed."
. . As the rocks cooled, magnetite acted as a catalyst to form organic compounds from fluids rich in carbon dioxide and water. In the Mars meteorite, the organic material did not originate from Martian life forms but formed directly from these chemical reactions within the rock, Steele and his colleagues figure.
. . This is the first study to show that Mars is capable of forming organic compounds at all. "This implies that building blocks of life can form on cold rocky planets throughout the universe."
Dec 11, 07: Scientists believe they have located a new brain area essential for good memory - the "irrelevance filter". People who are good at remembering things, even with distractions, have more activity in the basal ganglia on brain scans, the Swedish team found.
. . The work could help explain why some people are better at remembering things than others. Clinically, it could also aid the understanding of attention deficit hyperactivity disorder (ADHD).
Dec 11, 07: Human evolution has been moving at breakneck speed in the past several thousand years, far from plodding along as some scientists had thought, researchers said. In fact, people today are genetically more different from people living 5,000 years ago than those humans were different from the Neandertals who vanished 30,000 years ago, according to anthropologist John Hawks of the U of Wisconsin.
. . Many of the recent genetic changes reflect differences in the human diet brought on by agriculture, as well as resistance to epidemic diseases that became mass killers following the growth of human civilizations.
. . For example, Africans have new genes providing resistance to malaria. In Europeans, there is a gene that makes them better able to digest milk as adults. In Asians, there is a gene that makes ear wax more dry.
. . The changes have been driven by the colossal growth in the human population --from a few million to 6.5 billion in the past 10,000 years-- with people moving into new environments to which they needed to adapt, added Henry Harpending, a U of Utah anthropologist. "The central finding is that human evolution is happening very fast --faster than any of us thought", Harpending said.
. . The researchers looked for the appearance of favorable gene mutations over the past 80,000 years of human history by analyzing voluminous DNA information on 270 people from different populations worldwide. Data from this International HapMap Project, short for haplotype mapping, offered essentially a catalogue of genetic differences and similarities in people alive today. Looking at such data, scientists can ascertain how recently a given genetic change appeared in the genome and then can plot the pace of such change into the distant past.
. . Beneficial genetic changes have appeared at a rate roughly 100 times higher in the past 5,000 years than at any previous period of human evolution, the researchers determined. They added that about 7% of human genes are undergoing rapid, relatively recent evolution. Even with these changes, however, human DNA remains more than 99% identical, the researchers noted.
. . Science fiction writers have suggested a future Earth populated by a blend of all races into a common human form. In real life, the reverse seems to be happening. Residents of various continents becoming increasingly different from one another, researchers say.
. . If evolution had been proceeding steadily at the current rate since humans and chimps separated 6 million years ago, there should be 160 times more differences than the researchers found. "The past 10,000 years have seen rapid skeletal and dental evolution in human populations, as well as the appearance of many new genetic responses to diet and disease."
. . And they found that different changes are occurring in Africans, Asians and Europeans. In Sweden and Denmark, the gene that makes the milk-digesting enzyme lactase remains active, so almost everyone can drink fresh milk, explaining why dairy farming is more common in Europe than in the Mediterranean and Africa.
Dec 6, 07: A giant spitting cobra, measuring nearly nine feet and carrying enough venom to kill at least 15 people, has been discovered in Kenya. WildlifeDirect said the snake it described as the world's largest had been recognized as a new species. Common Spitting cobras, able to launch poison over a distance of several meters, are common to Kenya's lowland climates.
. . "A new species of giant spitting cobra is exciting and reinforces the obvious --that there have to be many other unreported species but hundreds are being lost as their habitats disappear under the continued mismanagement of our planet", said the group's chairman, Kenyan environmentalist Richard Leakey.
Dec 6, 07: Dogs can sort photographs into categories, in the same way that humans and other primates do, the British weekly New Scientist reports.
Dec 5, 07: An abattoir used by early Cypriots, a place where animals went to die, or a shelter that ultimately proved a death trap? Cypriot and Greek scientists are studying a collapsed cave filled with the fossilized remains of extinct dwarf hippopotamuses —-descendants of hippos believed to have reached the island a quarter-million years ago.
. . Paleontologists have unearthed an estimated 80 dwarf hippos in recent digs. Hundreds more may lie beneath an exposed layer of jumbled fossils. Scientists hope the fossil haul, tentatively dated to 9,000-11,500 B.C., could offer clues to when humans first set foot on this Mediterranean island. Until the Ayia Napa discovery, the earliest trace of humans on Cyprus dated to 8,000 B.C. But signs of human activity at the new dig could turn back the clock on the first Cypriots by as much as 3,500 years.
. . The dwarf hippopotamuses were herbivores, like their modern cousins, but were only about 2 1/2 feet tall and 4 feet long. Unlike modern hippos, whose upturned nostrils seem designed for swimming, Cypriot hippos had low-slung nostrils better suited to foraging on land. Panayides said the fossils show the Cypriot hippos had legs and feet adapted to land, enabling them to stand on their hind legs to reach tree branches.
. . Panayides said paleontologists theorize hippos may have swum or floated here during a Pleistocene ice age from land that is now Turkey or Syria. Lower sea levels at the time made Cyprus much larger than its present 3,570 square miles, meaning it was much closer to other lands. By some estimates, what is now Syria was a mere 18 miles away.
. . One cave found 20 years ago had evidence of fire, stone tools and scorched bones indicating dwarf hippos were hunted by humans. Carbon dating on those hippo fossils showed the site dated to 8,000 B.C. Evidence of human activity at Ayia Napa means the island may have been settled by humans as much as 3,500 years earlier.
. . A human footprint at the Ayia Napa site could bolster the theory that the island's earliest inhabitants could have driven the dwarf hippos to extinction through hunting.
Dec 5, 07: A Former Evangelical Minister Has a New Message: Jesus Hearts Darwin. Michael Dowd believes in both Christianity and evolution, and he's traveling the country in a van to share the good news.
Dec 5, 07: An African elephant can recognize dozens of kin by the signature smell of urine, and uses its powerful nose to keep track of their whereabouts, according to a study.
Dec 5, 07: Agression pheromones have been identified in mice that encourage fights between rival males. Scientists from Scripps Research Institute found that mice excrete at least two chemicals in their urine which make them brawl.
. . Nerves in the noses of male mice are able to detect these proteins in the urine of rivals. This is enough to stimulate aggressive behavior in these highly territorial rodents.
. . Previous experiments had shown that castrated males did not produce the aggression pheromone and did not elicit belligerent behavior from rivals. But when scientists swabbed urine from uncastrated males on the backs of castrated mice, other males displayed hostile behavior towards them once again.
Dec 5, 07: Chinese archaeologists have found fossils that prove pandas once roamed what is now the southern Chinese island of Hainan.
Dec 4, 07: Remains of a bus-sized prehistoric "monster" reptile found on a remote Arctic island may be a new species never before recorded by science, researchers said. Its estimated to measure nearly 13 meters long.
. . The short-necked plesiosaur was a voracious reptile often compared to the Tyrannosaurus rex of the oceans.
Dec 3, 07: Young chimps outperform their human counterparts in some short-term memory tests, Japanese researchers find.
Dec 3, 07: A partially mummified hadrosaur discovered by a teenager in North Dakota may be the most complete dinosaur ever found, with intact skin that shows evidence of stripes and perhaps soft tissue, researchers said. Enough of the animal remains to show it ran quickly and was far more muscular than scientists believed such dinosaurs were.
. . The creature is fossilized, with the skin and bone turned to stone. But unlike most dinosaur fossils, tissues are preserved as well. This includes large expanses of the animal's skin, with clear remains of scales. "This is not a skin impression. This is fossilized skin", Manning said. "When you run your hands over this dinosaur's skin, this is the closest you are going to get to touching a real dinosaur, ever."
. . The remains of the hadrosaur, dubbed Dakota, were found in 2000 by Tyler Lyson, then 17, on his uncle's ranch in North Dakota. The duckbilled hadrosaur, a plant-eating dinosaur that walked on two legs, lived 67 million years ago, during the late Cretaceous Period. It weighed close to 4,500 kg.
. . They persuaded the Boeing Company and NASA to use a huge computed tomography, or CT, scanner in Canoga Park, California, that is usually used to scan space shuttle parts. The dense fossil has taken months to scan, Manning said. "We will know in the next few days if the head is in there", he said. The tail piece turned up some surprises. The animal's back end is 25% larger than previously thought.
. . Locomotor biologist Bill Sellers of the U of Manchester used a computer program to reconstruct how the hadrosaur would have moved and came up with a picture of an animal that walked not upright, but with its head low to the ground and forearms almost touching. The strong muscles connecting its upper legs to its tail would have allowed it to run at speeds of up to 45 km an hour, well ahead of its predator, Tyrannosaurus rex.
. . Patterns in the scales resemble those associated with skin color changes in lizards. This provides the strongest evidence yet that the animal had stripes, Manning said.
. . Unlike the collections of bones found in museums, this hadrosaur came complete with skin, ligaments, tendons and possibly some internal organs, according to researchers.
. . The study is not yet complete, but scientists have concluded that hadrosaurs were bigger —-3 1/2 tons and up to 40 feet long-— and stronger than had been known, were quick and flexible and had skin with scales that may have been striped.
. . Because of chemical conditions where this animal died, fossilization —-replacement of tissues by minerals-— took place faster than the decomposition, leaving mineralized portions of the tissue. That does not mean DNA, the building blocks of life, can be recovered, Manning said. Some has been recovered from frozen mammoths up to 1 million years old, he said. At the age of this dinosaur, 65 million to 67 million years old, "the chance of finding DNA is remote."
. . Most dinosaur skeletons in museums, for example, show the vertebrae right next to one another. The researchers looking at Dakota found a gap of about a cm between each one. That indicates there may have been a disk or other material between them, allowing more flexibility and meaning the animal was actually longer than what is shown in a museum. On large animals, adding the space could make them a meter longer or more, Manning said.
Dec 1, 07: Remember biology class where you learned that children inherit one copy of a gene from mom and a second from dad? There's a twist: Some of those genes arrive switched off, so there is no backup if the other copy goes bad, making you more vulnerable to disorders from obesity to cancer.
. . Duke U scientists now have identified these "silenced genes", creating the first map of this unique group of about 200 genes believed to play a profound role in people's health. More intriguing, the work marks an important step in studying how our environment —-food, stress, pollution-— interacts with genes to help determine why some people get sick and others do not. Next comes work to prove exactly what role these genes play. "Some will be real gold and some will be fool's gold", Jirtle added.
. . Usually, people inherit a copy of each gene from each parent and both copies are active, programmed to do their jobs whenever needed. If one copy of a gene becomes mutated and quits working properly, often the other copy can compensate. Genetic imprinting knocks out that backup. It means that for some genes, people inherit an active copy only from the mother or only from the father. Molecular signals tell, or "imprint", the copy from the other parent to be silent.
. . Jirtle compared it to flying a two-engine airplane with one engine cut off. If the other engine quits, the plane crashes. In genetic terms, if one tumor-suppressing gene is silenced and the active one breaks down, a person is more susceptible to cancer.
. . Only animals that have live births have imprinted genes. It was not until 1991 that it was proved that humans had them. Until now, only about 40 human imprinted genes had been identified. The Duke map verified those 40 and identified 156 more. Researchers fed DNA sequences into a computer program that decoded patterns pointing to the presence of imprinted genes instead of active ones.
. . Many of the newly found imprinted genes are in regions of chromosomes already linked to the development of obesity, diabetes, cancer and some other major diseases, the researchers reported. One, for example, appears to prevent bladder cancer. A second appears to play a role in causing various cancers and may affect epilepsy and bipolar disorder.
. . Sometimes imprinting goes awry before birth, leaving a normally silenced gene "on" or silencing one that should not be. Faulty gene imprinting leads to some devastating developmental disorders, such as Angelman syndrome, which causes mental retardation.
. . Now a question is how imprinting may be changed to reactivate an imprinted gene after birth.
Nov 29, 07: One of our closest ancestors had more in common with gorillas than previously thought, with males of the species taking far longer to reach maturity than females, scientists said.
. . Males of Paranthropus robustus --an extinct relative of humans that lived almost 2 million years ago-- continued to grow well into adulthood, before a lucky few finally established "harems" of females for breeding. The result was a big difference in size between males and females.
. . Although modern human boys do mature later than girls, the difference is small. Male gorillas, by contrast, do not reach full dominant "silverback" status until many years after the females have already started to have offspring.
Nov 30, 07: Genes that can be pinned to intelligence are proving frustratingly hard to find. Researchers led by Robert Plomin of the Institute of Psychiatry in London obtained intelligence scores for 7,000 seven-year-olds based on verbal and non-verbal reasoning tests.
. . They also took DNA samples from the children in the hope of identifying genetic differences between the high and low scorers. The huge trawl identified 37 variants in six genes that appear to be play some role in differences in intelligence. But the individual effects of these genes was barely detectable. Together they account for just 1% of the variation in intelligence between individuals.
. . Previous research, based on twins and adopted children, suggests that about half of the variation of intelligence is due to upbringing and social factors, and the rest is inherited.
Nov 27, 07: A US genetic study bolsters claims that Native Americans are descended from one migrant group that crossed a lost land link from modern Siberia to Alaska --not waves of arrivals from Asia, as rival theories say. The new study by the U of Michigan examined genes of indigenous people from North to South America and from two Siberian groups.
. . Analysis found one unique genetic variant widespread across both the northern and southern American continents --suggesting that all Native Americans were descended from a single group, not various ones as the rival theory holds.
. . This variant "has not been found in genetic studies of people elsewhere in the world except eastern Siberia", the report said. The study also found that genetic diversity increased the further away people were from the Bering Strait --as would be expected if the migration were "relatively recent", the report said.
Nov 27, 07: A fossilized shark that swallowed a crocodile-like amphibian that, in turn, had gobbled up a fish has now been unearthed. This exceptional find marks the first time scientists have found direct evidence of such a complex, extinct food chain. Fossilized dung, or "coprolites", have revealed that some dinosaurs ate grass. "Prey, especially in the gut or intestines of fossil organisms, are very rarely preserved."
Nov 26, 07: A hoard of dinosaur bones has been discovered at the site of a planned desalination plant meant to deliver Australia's second biggest city from drought, forcing a re-think of the A$3 billion ($2.7 billion) project.
. . Melbourne plans to build one of the world's biggest water desalination plants to drought-proof the city, with construction to begin next year and up to 150 billion litres of drinking water a year flowing by 2011, rivaling a plant in Israel. The plant will extract salt from sea water through reverse osmosis, discharging salt waste into the ocean and pumping the purified water 85 km to Melbourne.
. . The fossilized bones, estimated to be 115 million years old and belonging to dinosaurs and ancient marine reptiles, were found on a windswept beach. "The rocks were deposited at a time when Australia was in the polar circle", she said.
Nov 23, 07: Sea anemones normally anchor themselves to the seafloor. But new species found lurking in the waters surrounding the windswept Aleutian Islands near Alaska swim and walk across the sea floor.
. . Scientists discovered the anemones, which could represent two species, as well as a new species of kelp as part of a two-year scientific survey of the waters around the Aleutians. Scientists say only about 10% of the species of life on this planet have been seen or catalogued.
. . The researchers are consulting experts to verify that the Aleutian anemones are in fact new species, but the consensus so far is that they are.
Nov 21, 07: The carnivorous pitcher plants that feed on insects in the Asian tropics may not snap shut like Venus flytraps, but they are smarter than they look. Rather than being passive pitfall traps, the tube-like pitchers of Nepenthes plants actually contain a clever slimy fluid --similar to mucus-- that produces powerful filaments to snare prey, French researchers said.
. . The unusual qualities of the fluid could one day be used to develop new, less environmentally harmful pesticides, the experts believe.
. . Just how pitcher plants catch their prey has intrigued biologists since Charles Darwin's time. Until now, it was thought that gravity and the slippery tube surface were the key, with the fluid in the pitcher simply helping digestion. The effect is seen even when the fluid is diluted more than 90% with water, as can happen during heavy rainfall in the jungles of Borneo, where many of the plants grow.
. . The researchers have yet to identify the molecules responsible for the elastic properties of the fluid, which appears to be unique in the plant kingdom. But they believe the ingredient could help produce better pesticides in the future.
Nov 21, 07: This was a bug you couldn't swat and definitely couldn't step on. British scientists have stumbled across a fossilized claw, part of an ancient sea scorpion, that is of such large proportion it would make the entire creature the biggest bug ever: 2.5M.
. . The discovery in 390-million-year-old rocks suggests that spiders, insects, crabs and similar creatures were far larger in the past than previously thought. "We have known for some time that the fossil record yields monster millipedes, super-sized scorpions, colossal cockroaches, and jumbo dragonflies. But we never realized until now just how big some of these ancient creepy-crawlies were", he said.
. . These scorpions "were dominant for millions of years because they didn't have natural enemies. Eventually they were wiped out by large fish with jaws and teeth."
. . Eurypterids, or ancient sea scorpions, are believed to be the extinct aquatic ancestors of today's scorpions and possibly all arachnids, a class of joint-legged, invertebrate animals, including spiders, scorpions, mites and ticks.
. . Braddy said the fossil was from a Jaekelopterus Rhenaniae, a kind of scorpion that lived only in Germany for about 10 million years, about 400 million years ago. He said some geologists believe that gigantic sea scorpions evolved due to higher levels of oxygen in the atmosphere in the past. Others suspect they evolved in an "arms race" alongside their likely prey, fish that had armor on their outer bodies. Braddy said the sea scorpions also were cannibals that fought and ate one other, so it helped to be as big as they could be.
Nov 16, 07: A strange-looking dinosaur with rows of tiny teeth crammed into the very front of its jaws and fragile air-filled bones may have been the "cow of the Mesozoic", and far more common than better-known dinosaurs, scientists said.
. . The researchers used a combination of computer modeling, X-rays and good old-fashioned digging to build a model of an elephant-sized animal that lived 110 million years ago in what is now the Sahara desert in Niger.
. . "In everyday life, this animal had its nose pointed towards the ground." What this says, argues Sereno, is that experts have long mistakenly believed that many herbivore dinosaurs behaved like living long-necked animals such as giraffes. "I think we were blindsided and missed the cows of the Mesozoic."
. . The researchers sawed a few teeth open. "You can actually see the daily increments of dentin", Sereno said. Nigersaurus was losing its teeth every 30 to 35 days, faster than any dinosaur known.
. . Sereno believes Nigersaurus and similar grazers were once the most common dinosaurs, but their fossils have been too fragile to have survived to be discovered. How does he know? Teeth. Similar teeth have been found in Europe, South America and in several parts of Africa. The vertebrae are hollow and the skull is so delicate that only bits and pieces remain from most of the animals. "It doesn't take much to weather these away."
Nov 15, 07: Tiny robots programmed to act like roaches were able to blend into cockroach society, according to researchers studying the collective behavior of insects. Cockroaches tend to self-organize into leaderless groups, seeming to reach consensus on where to rest together. For example, when provided two similar shelters, most of the group tended to gather under the same one.
. . Hoping to learn more about this behavior, researchers led by Jose Halloy at the Free U of Brussels, Belgium, designed small robots programmed to act like a cockroach. The robots didn't look like the insects and at first the roaches fled from them, but after the scientists coated the robots with pheromones that made them smell like roaches the machines were accepted into the group, nesting together with the insects.
. . Given a choice, roaches generally prefer a darker place and the robots were programmed to do the same. When given a choice of a darker or lighter shelter, 75% of the cockroaches and 85% of the robots gathered under the darker one.
Nov 15, 07: Ever wondered how we are able to conduct a conversation at a noisy party? Researchers from Japan, Canada and Germany have found that it is our left brain that picks out the desired sounds from a cacophony of loud, competing sounds.
Nov 15, 07: Scientists discovered a new dinosaur with mouth parts designed to vacuum up food. The 110 million-year-old plant eater was discovered in the Sahara Desert.
. . Paul Sereno named the elephant-sized animal Nigersaurus taqueti [Ny-zhier-], an acknowledgment of the African country Niger and a French paleontologist, Philippe Taquet. Sereno, a National Geographic explorer-in-residence and paleontologist at the U of Chicago, said the first evidence of Nigersaurus was found in the 1990s and now researchers have been able to reconstruct its skull and skeleton.
. . While Nigersaurus' mouth is shaped like the wide intake slot of a vacuum, it has something lacking in most cleaners —-hundreds of tiny, sharp teeth to grind up its food.
. . The 10-meter-long Nigersaurus had a feather-light skull held close to the ground to graze like an ancient cow. Its broad muzzle contained more than 50 columns of teeth lined up tightly along the front edge of tis jaw. Behind each tooth more were lined up as replacements when one broke off.
. . Using CT scans, the researchers were able study the inside of the animal's skull where the orientation of canals in the organ that helps keep balance disclosed the habitual low pose of the head, they reported.
. . Nigersaurus also had a backbone consisting of more air than bone. "The vertebrae are so paper-thin that it is difficult to imagine them coping with the stresses of everyday use —-but we know they did it, and they did it well."
Nov 14, 07: A tropical fish that lives in mangrove swamps across the Americas can survive out of water for months at a time, similar to how animals adapted to land millions of years ago, a new study shows.
. . The Mangrove Rivulus, a type of small tropical killifish, seeks refuge in shallow pools of water in crab burrows, coconut shells or even old beer cans in the tropical mangrove swamps of Belize, the US and Brazil. When their habitat dries up, they live on the land in logs.
. . The fish, whose scientific name is Rivulus marmoratus, can grow as large as three inches. They group together in logs hollowed out by insects and breathe air through their skin instead of their gills until they can find water again.
. . "We kicked over a log and the fish just came tumbling out." In lab tests, Taylor said he found the fish can survive for up to 66 days out of water without eating, and their metabolism keeps functioning.
. . Some other fish can survive briefly out of water. The walking catfish found in Southeast Asia can wriggle over land for hours at a time, while lungfish found in Australia, Africa and South America can survive out of water, but only in a dormant state. No other known fish can be out of water as long as the Mangrove Rivulus and remain active. The fish may hold clues to how animals evolved over time.
. . Surviving on land is not the only unusual behavior exhibited by the fish. They have both testes and ovaries and essentially clone themselves by laying their own, already fertilized eggs. "This is probably the coolest fish around, not only do they have a very bizarre sex life, but they really don't meet standard behavioral criteria for fishes", said Taylor in a summary of his paper.
Nov 14, 07: Eating your offspring may sound unthinkable, but animals from fish to birds are known to do it. Scientists have been unsure why such a behavior would have evolved, but a new study sheds light on the factors that may drive some parents to eat their young.
. . Zoologists have observed filial cannibalism, the act of eating one's offspring, in many different types of animals, including bank voles, house finches, wolf spiders and many fish species. Paradoxically, all of the species also care for the young that they don't eat.
. . Scientists were hard-pressed to explain how such seemingly opposing behaviors could co-exist in the same species and reasoned that there must be some evolutionary benefit to the practice.
. . Previous studies have focused on the idea that parents might be eating their own eggs because they get an energy benefit from it and might be using it as a source of food when other sources were scarce. But studies of some fish that had their diets supplemented by researchers came back with mixed results: While some stopped eating their offspring, others didn't.
. . They modeled different scenarios of "virtual organisms" with a computer, & found that several factors contributed. In some cases, cannibalizing their own young puts the same evolutionary pressure on the eggs that a predator would: the faster the eggs develop, the greater their chances of survival.
. . Cannibalism was also found to increase the parent's reproductive rate by apparently increasing mate attractiveness, though Klug says they're unsure as to why this might be.
. . Klug said filial cannibalism could be a way to root out offspring that take too long to mature and therefore require a little too much parental care—this strategy would conserve the parents' energy for subsequent, faster-developing batches of young.
Nov 14, 07: Clive Thompson on Why Science Will Triumph Only When Theory Becomes Law: Antievolution crusaders have figured out that language is the ammunition of culture wars. That's why they use those stickers. They take the intellectual strengths of scientific language —-its precision, its carefulness-— and wield them as weapons against science itself.
. . The defense against this: a revamped scientific lexicon. If the antievolutionists insist on exploiting the public's misunderstanding of words like theory and believe, then we shouldn't fight it. "We need to be a bit less cautious in public when we're talking about scientific conclusions that are generally agreed upon", Quinn says.
. . What does she suggest? For truly solid-gold, well-established science, let's stop using the word theory entirely. Instead, let's revive much more venerable language and refer to such knowledge as "law". As with Newton's law of gravity, people intuitively understand that a law is a rule that holds true and must be obeyed. The word law conveys precisely the same sense of authority with the public as theory does with scientists, but without the linguistic baggage.
. . Evolution is supersolid. We even base the vaccine industry on it: When we troop into the doctor's office each winter to get a flu shot — an inoculation against the latest evolved strains of the disease —-we're treating evolution as a law. So why not just say "the law of evolution"?
. . Best of all, it performs a neat bit of linguistic jujitsu. If someone says, "I don't believe in the theory of evolution", they may sound fairly reasonable. But if someone announces, "I don't believe in the law of evolution", they sound insane. It's tantamount to saying, "I don't believe in the law of gravity."
. . It's time to realize that we're simply never going to school enough of the public in the precise scientific meaning of particular words. We're never going to fully communicate what's beautiful and noble about scientific caution and rigor. Public discourse is inevitably political, so we need to talk about science in a way that wins the political battle —-in no uncertain terms.
. . At least, that's my theory.
Nov 13, 07: Like children who complain "no fair", capuchin monkeys throw fits when their companions get better treats. In a new study, envy reared its ugly head if capuchins, primates like us, landed slices of cucumber while their cage mates received tasty grapes—considered more desirable.
. . The recognition of an unfair situation could be critical for maintaining relationships in cooperative societies such as those of capuchins, as well as among humans, the researchers said. The study also suggests the roots of human fairness stretch well back in evolutionary time.
Nov 13, 07: Researchers who study the wilderness of heat-loving bacteria that thrives in Yellowstone's hot springs are starting to pay more attention to the even smaller organisms that keep those bacteria populations in check: viruses. Certain viruses appear to migrate around Yellowstone on steam droplets.
. . Researchers have been eager to find industrial uses for Yellowstone's bacteria. Cleaning smokestacks at coal-fired power plants is one possible application. But to do that sort of thing, scientists are discovering that the relationships between hot springs bacteria and the viruses that infect them could be very important. The scientists did some experiments and discovered that viruses can indeed travel by steam, much like how influenza spreads when people sneeze.
Nov 12, 07: Instead of being driven to extinction by death from above, dinosaurs might have ultimately been doomed by death from below in the form of monumental volcanic eruptions. The suggestion is based on new research that is part of a growing body of evidence indicating a space rock alone did not wipe out the giant reptiles.
. . Another leading culprit is a series of colossal volcanic eruptions that occurred between 63 million to 67 million years ago. These created the gigantic Deccan Traps lava beds in India, whose original extent may have covered as much as 1.5 million square km, or more than twice the area of Texas.
. . Arguments over which disaster killed the dinosaurs often revolve around when each happened and whether extinctions followed. Previous work had only narrowed the timing of the Deccan eruptions to within 300,000 to 500,000 years of the extinction event.
. . Now, research suggests the mass extinction happened at or just after the biggest phase of the Deccan eruptions, which spewed 80% of the lava found at the Deccan Traps.
. . They focused on marine fossils excavated at quarries at Rajahmundry, India, near the Bay of Bengal, about 1,000 km southeast of the center of the Deccan Traps. Specifically, they looked at the remains of microscopic shell-forming organisms known as foraminifera. "Before the mass extinction, most of the foraminifera species were comparatively large, very flamboyant, very specialized, very ornate, with many chambers", Keller explained. These foraminifera were roughly 200 to 350 microns
. . "When the environment changed, as it did around K-T, that prompted their extinction", she added. "The foraminifera that followed were extremely tiny, one-twentieth the size of the species before, with absolutely no ornamentation, just a few chambers." As such, these puny foraminifera serve as very distinct tags of when the K-T extinction event started.
. . The researchers found these simple foraminifera seem to have popped up right after the main phase of the Deccan volcanism. This in turn hints these eruptions came immediately before the mass extinction, and might have caused it.
. . Both an impact from space and volcanic eruptions would have injected vast clouds of dust and other emissions into the sky, dramatically altering global climate and triggering die-offs. Keller's collaborator, volcanologist Vincent Courtillot at the Institute of Geophysics in Paris, noted upcoming work from her collaborators suggests the Deccan eruptions could have quickly released 10 times more climate-altering emissions than the nearly simultaneous Chicxulub impact.
. . Although paleontologist Kirk Johnson at the Denver Museum of Nature and Science called these new findings "significant", he noted a great deal of evidence connected a single massive impact with the K-T extinction event. He suggested that advances in radioisotope dating could now hone down when the Deccan eruptions occurred to within 30,000 to 65,000 years.
[JKH: I've had a hypothesis about this for literally decades now. The rock hits Yucatan & shock waves travel into the Earth, being bent & focused by the core, then erupting in India. The top layer of earth bounces up like the balls in one of those swinging-ball mystery-motion toys. It seems to me it would result in exactly the formation of what is seen there. ... It would take a lot of calculation to check how wide & thick a layer would be thrown up, & how high.]
Nov 11, 07: Researchers have found a 10-million-year-old jaw bone in Africa they believe belonged to a new species of great ape that was close to the last common ancestor of gorillas, chimpanzees and humans.
. . The fragment was found along with 11 teeth in volcanic mud flow deposits in the Nakali region of Kenya, and suggested the creature was somewhere between the size of a female gorilla and a female orangutan, and fed on nuts, seeds and fruit.
. . The finding is significant as it gives credence to the theory that the evolution from ape to man may have taken place entirely in Africa. Prior to this finding, there had been so little fossil evidence in Africa dating between 7 to 13 million years ago that some experts began to surmise that the last common ancestor left Africa for Europe and Asia, and then returned later. But Kunimatsu said the findings suggested that the ancestor of African great apes and humans likely evolved in Africa.
Nov 9, 07: Some female toads are rather open-minded when it comes to choosing a mate, a study reveals.
. . US researcher Karen Pfenning found female spadefoot toads will flout the general evolutionary rule of not breeding with other species. She discovered that the amphibians, under some conditions, will mate with other species to help boost the survival rates of their offspring.
. . Spadefoots breed in small ponds, which can often dry out, killing any developing tadpoles. When a pond is very shallow, one species of female spadefoot, S. bombifrons, will often mate with another closely relates species, D. multiplicata, rather than males of their own kind. The hybrid offspring between the two species develop rapidly, meaning that they are more likely to survive if the pond dries out quickly.
Nov 8, 07: Australian scientists studying humpback whales sounds say they have begun to decode the whale's mysterious communication system, identifying male pick-up lines and motherly warnings.
. . Wops, thwops, grumbles and squeaks are part of the extensive whale repertoire recorded by scientists from the U of Queensland working on the Humpback Whale Acoustic Research Collaboration (HARC) project. Recording whale sounds over a three-year period, scientists discovered at least 34 different types of whale calls. "I was expecting to find maybe 10."
. . Many of the whale sounds could overlap in meaning, said Dunlop, but some had clear meanings. A purr by males appeared to signify the male was trying his luck to mate a desirable female. High frequency cries and screams were associated with disagreements, when males jostled to escort females during migration, she said.
. . A wop sound was common when mothers were together with their young. "The wop was probably one of the most common sounds I heard, probably signifying a mum calf contact call", said Dunlop.
. . Dunlop stopped short of defining the whale communication as a language, but said there were clear similarities with human interaction. "Its quite fascinating that they're obviously marine mammals, they've been separated from terrestrial mammals for a long, long, long time, but yet still seem to be following the same basic communication system", she said.
. . Dunlop hopes further research on the subject will help reveal the effect of boats and man-induced sonar on migrating whales.
Nov 8, 07: A lone molar belonging to a hoofed mammal stayed tucked beneath a pillow of volcanic rock in central India for more than 65 million years. Recently uncovered, the tooth predates similar fossils found across the globe.
. . The dental discovery sheds light on the evolution of adaptations that allowed a group of mammals called ungulates to thrive as expert grazers. It also suggests, according to newly published research on the tooth, that the Indian subcontinent could be the point of origin of many groups of mammals.
. . The lower right molar, about half the size of an ant (2.5 mm long), was found embedded in central India's Deccan volcanic flows. The researchers estimate the tooth dates back to the late Cretaceous period (144 million to 65 million years ago), a time when India was not connected with other continents and dinosaurs still walked the Earth.
. . The fossil belonged to a new species of ungulate dubbed Kharmerungulatum vanvaleni, a hoofed animal related to modern horses, cows, pigs, sheep and deer. And it represents the oldest known evidence for the so-called archaic ungulates (small, primitive hoofed mammals), predating by millions of years the explosion of mammalian life that occurred during Paleocene Epoch, from 65 million to nearly 55 million years ago.
. . The teeth of mammals living during the late Cretaceous, Prasad noted, generally sported sharp and pointy cusps and, over evolutionary time, dental modifications led to expert grinders. However, the tooth of the new mammal was flat and broad, suggesting it was already adapted for munching grass rather than for tearing through meaty meals.
Nov 7, 07: Fear may be linked to the sense of smell, and can be switched off simply by shutting down certain receptors in the brain, Japanese scientists have found. In an experiment with mice, the researchers identified and removed certain receptors on the olfactory bulb of their brains --and the result was a batch of fearless rodents.
. . To prove their point, the scientists showed pictures of a brown mouse within an inch of a cat, sniffing up its ear, kissing it and playing with its predator's collar. "They detect the smell of predators ... like a cat and urine of a fox or snow leopard, but they don't display any fear. They even show very strong curiosity but they can't tell the smell is a sign of danger."
. . Mice have about 1,000 smell receptor genes, while humans have only 400 functioning ones and about 800 non-active ones.
Nov 7, 07: For more than a century, scientists have debated how birds evolved flight. Some thought birds had ground-dwelling ancestors, developing flight by taking off from the ground. Others figured birds evolved from tree-dwellers, developing flight by first gliding from branches. It now seems early birds might have preferred life on the ground.
. . In the past 15 years, researchers have uncovered a wealth of fossils of dinosaurs that could help settle the controversy and are already revealing more about how early birds lived roughly 150 million years ago. These creatures were seemingly on the way to becoming birds —"intermediates that had feathers, that were developing wings, that were forming beaks," said functional anatomist Christopher Glen at the U of Queensland in Australia.
. . Initially, Glen and colleague Michael Bennett looked at toe claws from 249 species of modern birds. They found that the more hooked the claws were, as is the case with woodpeckers, the more the birds preferred foraging in trees, "as curved claws would provide them a better grip there."
. . The scientists then looked at how curved the claws of early birds and their immediate bird-like dinosaur ancestors were. These all resembled the straighter claws of modern birds that favored the ground, such as those of turkeys, roadrunners and ostriches. "We're not saying we can resolve the entire story about bird flight just by looking at one feature of the anatomy", he said. "But their claws do suggest they spent more time on the ground."
Nov 7, 07: As if tiny flashlights were hidden inside its body, a fish-like creature emits fluorescent flecks, a flashing ability previously considered unique to jellyfish and corals. Researchers found that the bodies of amphioxus, also called lancelets, contain green fluorescent proteins that could act as a sunscreen or stress shield that protects the animals from environmental changes.
. . The finding suggests fluorescence (not to be confused with bioluminescence) might be more prevalent across the animal kingdom than previously thought. Bioluminesce, the result of chemical reactions that release energy in the form of light. Another form of light emission seen in certain minerals is called phosphorescence, a process in which energy is absorbed by a substance and then released slowly in the form of light. Fluorescence occurs when light is absorbed at one wavelength and then re-emitted at another nearly immediately.
. . The proteins were most similar to those found in corals, which the researchers say is interesting because the two animal groups are separated by billions of years of evolution. The finding indicates the fluorescence ability was preserved and so must play some important ecological function.
Blue whales make a "pulsing rumble" --the loudest noise made by any animal on Earth-- to attract mates.
Nov 6, 07: Dinosaurs like Velociraptors owe their fearsome reputation to the way they breathed, according to a UK study. They had one of the most efficient respiratory systems of all animals, similar to that of modern diving birds like penguins, fossil evidence shows. It fuelled their bodies with oxygen for the task of sprinting after prey, say researchers at Manchester U.
. . The bipedal meat-eaters, the therapods, had air sacs ventilated by tiny bones. Modern-day birds have a highly specialized respiratory system, made up of a small rigid lung and around nine air sacs. The bellows-like movement of the sternum and ribs moves air through the system. The small bones act as levers to move the ribs and sternum during breathing. They have become adapted in different types of birds to deal with different ways of getting around. The bones are shortest in runners like emus that don't need large breast muscles for flight, intermediate in flying birds and longest in divers such as the penguin.
Nov 6, 07: Our brains can turn down our ability to see to help them listen even harder to music and complex sounds, say experts.
. . A US study of 20 non-musicians and 20 musical conductors found both groups diverted brain activity away from visual areas during listening tasks. Scans showed activity fell in these areas as it rose in auditory ones. "Imagine the difference between listening to someone talk in a quiet room and that same discussion in a noisy room --you don't see as much of what's going on in the noisy room."
Nov 5, 07: Japanese scientists have identified two light receptors in marine algae which appear to be responsible for the proliferation of these plants. The scientists hope to use the findings to control unwanted algal growth, such as red tides, or to cultivate coveted species of kelp that are used as food.
. . In their experiment, the scientists removed the receptors genetically from a species of algae, called vaucheria, and found that the plant could no longer grow even though it was exposed to blue light for the next six months. Blue light is critical for the survival and growth of marine plants, as light of other wavelengths cannot penetrate the thick water mass.
Nov 2, 07: A genetically modified "supermouse" which can run twice as far as a normal rodent has been created by scientists working in the US. It also lives longer, and breeds later in life compared with its standard laboratory cousin.
. . The mice were produced to study the biochemistry at play in metabolism and could aid the understanding of human health and disease. The GM rodents can run five to six kilometers at a speed of 20 meters per minute on a treadmill, for up to six hours before stopping. "They are metabolically similar to Lance Armstrong biking up the Pyrenees; they utilize mainly fatty acids for energy and produce very little lactic acid."
. . "The muscles of these mice have many more mitochondria. These are the little 'engines' in the cell that produce energy. For some reason, the number of mitochondria are around 10 times more than we see in the muscle of their littermates." The scientists found their new mice would eat twice as much as normal mice - but weigh half as much. They could also give birth at three years old - which in human terms is akin to an 80-year-old woman giving birth.
. . One criticism of the work is that it could open the door to abuse, with the spectre of athletes resorting to gene therapy to try to improve their performance. But Professor Hanson played this down. "Right now, this is impossible to do --putting a gene into muscle. It's unethical. And I don't think you'd want to do this. These animals are rather aggressive, we've noticed."
Nov 2, 07: A gliding mammal that lives in the forests of south-east Asia is our closest relative after apes, monkeys and lemurs, a DNA study shows. Colugos are the "sisters" of primates, sharing a common ancestor some 80 million years ago when dinosaurs had their heyday, say US scientists. Until now, many experts thought tree shrews were closer to primates.
. . The team calls for urgent action to decipher the full genome sequence of colugos. The size of a large squirrel, they use a special fold of skin to glide from tree to tree in tropical rainforests.
Oct 31, 07: The first full genetic map of a cat --a domestic pedigreed Abyssinian-- is already shedding light on a common cause of blindness in humans and may offer insights into AIDS and other diseases, researchers reported. And the cat genome shows some surprising qualities that cats and humans appear to have uniquely in common.
. . The cat, named Cinnamon, is descended from lab cats bred to develop retinitis pigmentosa, a degenerative eye disease that causes blindness and which affects 1 in 3,500 Americans. O'Brien said a study of her genes can help uncover some of the causes of the incurable condition and may help find treatments for it.
. . They are the only animals besides humans who naturally become sick from immune deficiency viruses.[ahem... SIV... Simian?] People get HIV, which causes AIDS, while the feline immunodeficiency virus or FIV causes a similar disease in cats. The discovery of feline leukemia virus in the 1960s led scientists to realize that viruses can cause cancer.
. . Researchers can compare the cat genome to those of the six other mammal genomes that have been finished --the human, chimpanzee, mouse, rat, dog, and cow --to figure out differences in biology, evolution and disease. O'Brien said this comparison already demonstrates something interesting that happened as so many different species evolved from a tiny, shrewlike ancestor that outlived the dinosaurs.
. . "The order of genes in cat is remarkably similar to the order of genes in the ancestor of all placental mammals. The two species that have that similarity are humans and cats. Other species have a reshuffled genome, like a deck of cards. The cat and the humans are pretty much similar to the way it was, which means the good model didn't get fiddled with."
Oct 31, 07: Giant hyenas, sabretoothed cats, giraffes and zebras lived side by side in Europe 1.8 million years ago. The creatures' remains were among a vast fossil hoard unearthed at an ancient hyena den in the Granada region of south-east Spain. The area appears to have been a crossroads where European animals mixed with species from Africa and Asia. About 4,000 fossils have been found at the unique site. They also include gazelles, wolves, wild boar, a giraffe resembling a modern okapi, and lynx.
. . The Fonelas P-1 site is regarded as extremely important, because it dates to a time --the boundary between the Pliocene and Pleistocene Epochs-- when early humans are thought to have first left Africa to colonise Europe and Asia.
Oct 31, 07: Most of the cells in your body are not your own, nor are they even human. They are bacterial. From the invisible strands of fungi waiting to sprout between our toes, to the kilogram of bacterial matter in our guts, we are best viewed as walking "superorganisms", highly complex conglomerations of human cells, bacteria, fungi and viruses. Individuals can have very different responses to drugs, depending on their microbial fauna.
. . The scientists concentrated on bacteria. More than 500 different species of bacteria exist in our bodies, making up more than 100 trillion cells. Because our bodies are made of only some several trillion human cells, we are somewhat outnumbered by the aliens. It follows that most of the genes in our bodies are from bacteria, too.
. . Luckily for us, the bacteria are on the whole commensal, sharing our food but doing no real harm. (The word derives from the Latin meaning to share a table for dinner.) In fact, they are often beneficial: Our commensal bacteria protect us from potentially dangerous infections. They do this through close interaction with our immune systems.
. . The concept of this superorganism could have a huge impact on our understanding of disease processes. "Individuals can have very different responses to drug metabolism and toxicity. The microbes can influence things such as the pH levels in the gut and the immune response, all of which can have effects on the effectiveness of drugs", Wilson said.
. . The human genome does not carry enough information on its own to determine key elements of our own biology.
Oct 29, 07: A rock that sat untouched in a Pennsylvania museum's fossil collection for years has rare full-body imprints of not just one, but three, ancient amphibians. The body impressions of the salamander-like creatures are estimated to be 330 million years old, or about 100 million years before the first dinosaurs appeared.
. . Many ancient footprints have been found, but a full-body animal impression is unusual. The three impressions show the foot-long temnospondyls had webbed feet and smooth skin similar to modern-day amphibians.
Oct 29, 07: A 53-million-year-old spider has been revealed in exquisite detail by scientists from the UK and Belgium. The ancient creepy-crawly had been trapped in amber and preserved in a lowland area around Paris.
. . The scientists reconstructed the 1mm creature's original appearance using an X-ray-based medical imaging technique. This is the first time that the medical imaging technique, known as Very High Resolution X-Ray Computed Tomography, has been used to investigate a fossil in amber --and Dr Penney said it had the potential to "revolutionize" the way fossils were studied. The spider is a male and a species new to science.
Oct 25, 07: Some Neandertals may have had fair skin and red hair, giving them an appearance resembling modern Europeans, an international team of researchers said. The researchers homed in on the MC1R gene linked to hair and skin color and used DNA analysis to find a variation that produced the same kind of pigmentation changes as in humans with red hair and pale skin. Light skin would have been an evolutionary advantage for Neandertals by allowing them to soak up more vitamin D from the sun in cloudy Europe.
. . The study, published in the journal Science, comes a week after another set of researchers looking at a different gene said Neandertals may have been capable of sophisticated speech. "The papers make Neandertals more like modern Europeans, with light skin and hair color and language abilities, and yet there are no signs of interbreeding with modern humans."
. . Controversial findings last year suggested they might have survived until as recently as 24,000 years ago.
Oct 23, 07: Our genes and not just our upbringing may play a key role in our food likes and dislikes, UK researchers believe. Experts from Kings College London compared the eating habits of thousands of pairs of twins. Identical twins were far more likely to share the same dietary patterns --like a penchant for coffee and garlic [not together, I assume!]-- suggesting tastes may be inherited.
. . A health psychologist said this meant childhood food foibles might be harder to put right than previously thought. Their results, published in the journal Twin Research and Human Genetics, suggested that between 41% and 48% of a person's leaning towards one of the food groups was influenced by genetics.
. . The strongest link between individual liking and genes involved a taste for garlic and coffee.
Oct 23, 07: Large, carnivorous dinosaurs roamed southern Australia 115 million years ago, when the continent was joined to the Antarctica, and were padded with body fat to survive temperatures as low as -30 C. Standing about 3.7m tall, these hardy creatures inhabited the area close to the South Pole for at least 10 million years during the Cretaceous period, an expert said.
. . Palaeontologists from Australia and the US came by their findings after uncovering three separate fossil footprints measuring about 30cm long, each with at least two or three partial toes.
. . Australia was once part of the southern supercontinent of Gondwana, which also included South America, Africa, India and Antarctica. Gondwana began to break up about 120 million years ago and Australia separated from Antarctica about 50 million years ago and began moving northwards. We think they were warm-blooded", Rich added.
. . From the size of their feet, the experts figured they were up to 1.5 - 1.7m high at the hip. "You are talking about an animal that's about 3.7 meters tall, or about the size of a small adult tyrannosaurus", Rich said.
Oct 22, 07: China has built a large earth dam to protect a dinosaur fossil site from being washed away by floods.
Oct 22, 07: The son of a man who died of cardiac arrest at age 59 and of a woman who is still playing golf at 85, Craig Venter has identified genes in his map both for heart disease and longevity. However, he estimates that scientists will need a critical mass of 10,000 human genomes in order to engage in the type of analysis that will lead to major, unequivocal insights about genetic traits.
Oct 19, 07: A family of proteins known to fight off microbes surprisingly also helps determine whether a poodle's coat will be black, white or somewhere in between, U.S. researchers said in a finding that may also help explain why people come in different colors and weights.
. . Researchers at Stanford U in California studied the DNA of hundreds of dogs, looking for a gene mutation that controls coat color. "When we did genetic mapping and identified the gene responsible, it was a surprise", said Dr. Gregory Barsh.
. . It turns out the gene that controls coat color in dogs also controls a family of proteins called defensins that are thought to defend the body from invading microbes. "They're called defensins because people think their function is to defend against microbes", Barsh said. "No one has really been able to prove the defensins are defensive."
. . Instead of strictly playing a role in immunity, Barsh thinks they may play a bigger role. "They are evolution's way of responding to things that change rapidly on an evolutionary timescale", he said, something that also makes them appealing in terms of immunity.
. . "One of the things that changes very rapidly during evolution are pathogens", Barsh said. "We wonder if maybe defensins might be involved more broadly in dealing with environmental challenges that are faced by organisms." That could explain coat color, which could work as camouflage to better adapt to one's environment.
Oct 18, 07: Neandertals might have spoken just like humans do now, new genetic findings suggest. Neandertals are humanity's closest extinct relatives. Since their discovery more than 150 years ago, researchers have found out they could make tools just like our ancestors could, but whether Neandertals also had advanced language, rather than mere grunts and groans, has remained hotly debated.
. . Scientists investigated DNA from Neandertal bones collected from a cave in northern Spain, concentrating on a gene, FOXP2, which is to date the only one known to play a role in speech and language. People with an abnormal copy of this gene have speech and language problems.
. . Genes similar to FOXP2 are found throughout the genomes of the animal kingdom, from fish to alligators to songbirds. The molecule that human FOXP2 generates differs from chimpanzee FOXP2's by just two amino acids, the building blocks of proteins.
. . Past research suggests the gene's modern human variant evolved fewer than 200,000 years ago. Now scientists find the Neandertal FOXP2 gene is identical to ours. The ancestors of Neandertals diverged from ours roughly 300,000 years ago, according to the latest thinking.
. . Krause noted that some might suggest that interbreeding or "gene flow" (aka sex) between modern humans and Neandertals led to us having FOXP2 in common. "However, we see no evidence for gene flow in the Y chromosome sequences", he said. Instead, the modern human and Neandertal Y chromosomes are substantially different genetically.
Oct 18, 07: Scientists think they may have found out how reef-building corals manage to coordinate their sex lives in moonlight bay. In late spring, it's reef madness as corals release sperm and eggs into the water for a few nights after a full moon.
. . But how do they know? While corals don't have eyes, they are able to sense changes in light —-especially blue light-— and respond to them. The corals contain ancient proteins called cryptochromes which react to light. Cryptochromes have also been found in mammals and insects where they effect the circadian clock that regulates the daily rhythms of life.
. . This finding indicates that the basic means used by mammals today to regulate daily patterns was in use at the beginnings of multicellular animals, the researchers said. And, they added, it supports the idea that these proteins evolved under the blue light of the ancient seas.
Oct 18, 07: Elephants can tell whether a human is a friend or foe by their scent and colour of clothing, according to Fife experts.
. . The study found African elephants reacted with fear when they detected the scent of garments previously worn by men of the Maasai tribe. Maasai men are known to demonstrate their virility by spearing elephants.
. . The elephants also responded aggressively to red clothing, which is characteristic of traditional Maasai dress. However, the elephants showed much milder reaction to clothing previously worn by the Kamba people, agriculturalists who pose little threat.
. . "We think that this is the first time that it has been experimentally shown that any animal can categorise a single species of potential predator into subclasses based on such subtle cues."
. . They found that Maasai-scented clothing motivated elephants to travel significantly faster in the first minute after they moved away. The elephants also travelled further in the first five minutes, and took significantly longer to relax after they stopped running away.
Oct 17, 07: The earliest evidence for the existence of reptiles has been found in Canada. The 315 million-year-old fossilized tracks give an insight into a key milestone in the history of life, when animals left water to live on dry land. The footprints suggest reptiles evolved between one and three million years earlier than previously thought. The prints showed that the hands had five fingers and scales, sure evidence they were made by reptiles and not amphibians."
Oct 17, 07: Scientists exploring a deep ocean basin in search of species isolated for millions of years found marine life believed to be previously undiscovered, including a tentacled orange worm and an unusual black jellyfish.
Oct 15, 07: Brazilian and Argentine paleontologists have discovered the largely complete fossil of a new species of giant dinosaur that roamed what is now northern Patagonia about 80 million years ago.
. . The herbivorous Futalognkosaurus dukei measured an estimated 105 feet to 112 feet from head to tail and was as high as a four-story building. It is one of the three biggest dinosaurs yet found in the world. "It's a new species, it's a new group." The find pointed to a new lineage of titanosaurs, with particularly bulky necks, he said. "Its neck was very big in diameter, strong and huge."
. . Fossilized remains of an ecosystem from the same Late Cretaceous age, including well-preserved leaves and fish, were also found. The fossil was 70% preserved, which compares to about 10% for other giant dinosaur finds in the world.
. . Some of the leaves made part of the diet of the titanosaur and other specimens found there. The researchers said the fossilized ecosystem pointed to a warm and humid climate in Patagonia, which had forests during the Late Cretaceous period. The area is steppe-like now and almost bare of vegetation.
. . Researchers believe the carcass of the giant dinosaur, which died of unknown causes, its flesh devoured by predators, was washed into a nearby slow-flowing river, where it created a barrier, accumulating bones and leaves in its structure for many years until all became fossilized.
. . A fossil of a carnivorous theropod Megaraptor found at the site contained a complete and articulated arm with very large sickle-shaped claws. Previously, similar fragmented bones were interpreted as a foot, researchers said.
Oct 13, 07: An 85 million-year-old dinosaur skull --a herbivore called hadrosaurid-- has been found in southwestern Japan, one of the oldest discoveries of its kind in the country.
. . Hadrosaurids, which were seven to eight meters tall, are also known as "duck-billed dinosaurs" because of their heads' resemblance to ducks, with a wide and flat bill similar-looking to that of a platypus.
Oct 11, 07: One microscopic organism has thrived despite remaining celibate for tens of millions of years thanks to a neat evolutionary trick, researchers said. Asexual reproduction has allowed duplicate gene copies of the single-celled creatures --called bdelloid rotifers-- to become different over time. This gives the rotifers a wider pool of genes to help them adapt and survive, the researchers said.
. . The question, Tunnacliffe said, was how the creatures found in pools of water accomplished this feat without the gene-swapping made possible by sexual reproduction. "Sexual reproduction is supposed to be a good thing in evolution."
. . These creatures get around that problem with the evolutionary trick that allows their genes to drift apart and evolve on their own, Tunnacliffe said, after using molecular cloning techniques. "No sex means the genes can evolve in different directions," he said. "It is like you have a bigger gene pool to select from for different functions in evolution."
. . The theory of natural selection says sex mixes up the genes to cope with unexpected changes in a treacherous world. Some genetic changes are good and boost survival, for example against new strains of disease, but others lead to conditions like cystic fibrosis in humans.
Oct 10, 07: The ancestors of humanity are often depicted as knuckle-draggers, making humans seem unusual in our family tree as "upright apes." Controversial research now suggests the ancestors of humans and the other great apes might have actually walked upright too, making knuckle-walking chimpanzees and gorillas the exceptions and not the rule.
. . Filler analyzed how the spine was assembled in more than 250 living and extinct mammalian species, with some bones dating up to 220 million years old. He discovered a series of changes that suggest walking upright --and not with our knuckles-- might actually have been the norm for the ancestors of today's great apes.
. . In most creatures with a backbone, the body is separated roughly in half by a tissue structure that runs in front of the spinal canal. This "horizontal septum" divides the body into a dorsal part (corresponding to the back side of humans), and a ventral part (or the front half).
. . A strange birth defect in what may have been the first direct human ancestor led this septum to cross behind the spinal cord in the lumbar or lower back region-an odd configuration more typical of invertebrates. This would have made horizontal stances inefficient. "Any mammal with this set of changes would only be comfortable standing upright."
. . This change to an upright posture could have occurred "very abruptly, with just a few shifts in 'homeotic' genes, or ones responsible for how the body plan is laid out", Filler said.
. . The earliest known bipedal apes were thought to date back as far as some 6 million years or so. Now Filler's new findings suggest the earliest upright ape known so far was the extinct hominoid, Morotopithecus bishopi, which lived in Uganda more than 21 million years ago.
. . This research pushes back the date for the origins of bipedalism roughly 15 million years, to before the last common ancestor of humans, chimps, gorillas and orangutans, as well as lesser apes such as gibbons. The results match up with recent findings that suggest upright walking might have started before humanity's ancestors even left the trees.
. . "If you look at baby siamangs, which are a kind of gibbon, you'll see them walk bipedally on their own", Filler said. "It's just their natural way of walking. They never knuckle walk."
Oct 3, 07: Scientists have uncovered thousands of marine microbes --including never-before-seen bacteria-- thriving deep in the sea near cracks in the Earth's crust where warm fluids and cold sea water mix, U.S. researchers said.
. . Using new DNA sequencing techniques, the researchers have identified as many as 37,000 different kinds of bacteria huddled near two hydrothermal vents on an underwater volcano off the Oregon coast. Her research is part of an international effort to create a census of marine microbes, which make up as much as 90% of the total ocean biomass by weight.
. . Huber and colleagues focused their study on a gene that is common to all microbes that is essential for protein synthesis. "You have it. I have it. Even your dog has it. And microbes have it", Huber said. Her team looked at 900,000 of these genes, a massive undertaking that allowed her to arrive at an estimate of the number of microbes in the sample.
. . "A lot of people don't realize that microbes make living on Earth possible. They produce the oxygen we breathe. They have been on this planet for 3.5 billion years", she said. "We really need to understand who is there and what they're doing because things are changing, and they're changing rapidly, and we don't even know what the baseline is supposed to be." And without that, she said, "We're not going to know if things are changing."
Oct 4, 07: One of Earth's oldest types of plants, the primitive cycad, uses heavy perfume, heat and a bit of guile to lure tiny insects into a strange pollination dance, U.S. researchers said. They're ancient tropical plants with large seed cones that are often taken for palm trees. These plants date back nearly 300 million years.
. . During the pollination period, called coning season --which occurs every year or once every several years-- the male plants emit a scent to attract flying insects called thrips into their pollen-filled, pine cone-like structures.
. . Once the thrips have dallied a while --eating and covering their tiny bodies with pollen-- male cycads turn up the heat and the stink, literally. Male cycads can heat their cones up some 25 degrees hotter than the surrounding air, with some males reaching 38 degrees C. They also emit a strong odor --the chemical beta-myrcene-- which is attractive to thrips at low levels, but becomes repellent at higher concentrations. The whole process is designed to evict the pollen-covered thrips from the male cones.
. . That's where the female cycads, with their more subtle fragrance, offer a more attractive and hospitable environment. The thrips stumble in, find no food, and leave pollen behind.
. . "We know a lot about crop pollination", she said. "But if our interest is to help preserve plants on the planet, we need to understand how these pollination systems work."
Oct 4, 07: The first video images from tiny cameras attached to New Caledonian crows show they use tools to search for food even more than previously thought, researchers said. The cameras strapped to the tail feathers of the crows show the birds scraping grass stems on the ground to search for food in a technique not previously recorded. The footage also revealed the birds kept "good" ones to use again, adding to evidence the birds are as sophisticated as chimps in using implements --as humans do.
. . It's one of just three bird species known to use tools. The Galapogas Woodpecker Finch uses cactus spines to fish while the Egyptian vulture cracks open ostrich eggs with stones, Rutz said.
. . Researchers knew these birds used tools like the edge of palm leaves as a sort of hook but the videos showed the crows scraping grass stems on the ground in search of food, much like the way chimps probe for termites with sticks, Rutz said. The birds were probably foraging for insects to eat.
. . More surprising was that the birds flew off with certain tools in their beaks and then reused them later, even after they had set the implements aside and even though the island was full of similar materials, he added.
Oct 4, 07: Scientists have found in southern Utah a nicely preserved skull with jaws containing 800 teeth, scaly skin impressions and other fossil remains of a new species of duck-billed dinosaur from 75 million years ago. The bipedal herbivorous dinosaur, named Gryposaurus monumentensis, was about 30 feet long and pigged out on plenty of plants.
. . This is the fourth recognized species of Gryposaurus. The first was found almost a century ago. Gates said this discovery sheds light on what was going on in this part of North America about 10 million years before the dinosaurs went extinct.
. . In addition to this skull, they found a second Gryposaurus with a partial skull and partial skeleton, but with the tail completely intact. Skin impressions --only rarely fossilized-- showed the dinosaur was covered with gravelly looking scales, with some larger scales shaped a bit like a butterfly.
. . During the late Cretaceous, the last of the three periods in the age of dinosaurs, it was wet and lush, with lots of ponds, rivers and creeks. At the time, North America was split down the middle by a shallow sea.
. . At least 30 feet long and 10 feet tall with a robust jaw and thick bones, the 75-million-year-old animal was like a duck-billed dinosaur on steroids. However, the duck-billed dinosaur's teeth and size would not have been much of a defense against area predators such as the tyrannosaur. Scientists also aren't sure if the new dinosaur was a loner or traveled in herds for protection because so few skeletal remains have been found.
Oct 1, 07: Neandertals, the stocky kin of modern humans, were far more widespread geographically than previously thought, with some trekking into southern Siberia before vanishing about 30,000 years ago, scientists said
. . Researchers led by Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, found that Neandertals spread 1,250 miles further east than scientists had commonly believed.
. . The scientists used genetic tests to determine that three fragmentary bones previously found in the Altai region of southern Siberia were indeed those of a Neandertal. They also confirmed that a child's skeletal remains from Teshik-Tash in the Central Asian nation of Uzbekistan were from a Neandertal.
. . Scientists previously had established that Neandertals lived in Europe, the Middle East and parts of Asia before their disappearance. "Intriguingly, their presence in southern Siberia raises the possibility that they may have been present even farther to the east, in Mongolia and China", the researchers wrote in the journal Nature.
. . Traits typical of Neandertals appear in remains dating from 400,000 years ago, and Neandertals disappeared about 30,000 years ago. The fact that their geographic range was even bigger than previously thought makes their disappearance all the more mysterious, Paabo said.
Oct 1, 07: The ancient saber-toothed cat had some pretty scary dentures, but when it came down to actually biting, well, it was no lion. In fact, a study of the cat's jaw indicated it has only about one-third the biting power of a modern lion. "The sabercat had an immensely powerful body, perfect for wrestling large prey to the ground, and our models show that it needed to do this before trying a bite."
Oct 1, 07: A study finds wisdom teeth may only exist because of a weakness in a developmental mechanism that allows them to cram their way into the back of the jaw. Molars are the rearmost teeth in the mouth of most mammals. Adult humans have 12 molars (three on each side of the upper and lower jaws), and the last of each group is called the wisdom tooth.
. . Molars usually pop up from front to back, with the wisdom teeth appearing last between the ages of 16 and 24. If they start to crowd the jaw line and push the other teeth around, then its time for that dreaded dental procedure: the wisdom-tooth extraction.
. . One thing about molars that has perplexed scientists is why some people have very large wisdom teeth, while others (lucky for them) might not have any at all. To help answer this question, researchers at the U of Helsinki in Finland cultured mice teeth in a Petri dish. They found that the balance between two molecular mechanisms, activation and inhibition, govern how many teeth form from the tooth germ (the small bud of tissue that will later form the tooth) and how big the teeth are.
. . When the two mechanisms are in balance, all three teeth form and are about the same size. But if the two don't balance, the size of the teeth differs. If activation wins out, each tooth is successively larger, with the wisdom tooth becoming the bully of the bunch and causing a real mouth-ache. In extreme cases, a fourth molar might even rear its ugly head.
. . On the other hand, if inhibition wins out, the teeth get successively smaller, so the wisdom tooth is the runt of the litter. Run to its extreme, this situation could prevent the wisdom tooth from forming altogether.
. . Most early humans had all their wisdom teeth, with all of them measuring about the same size, so the two forces were likely in balance then, said study team member Jukka Jernvall.
. . Even with wisdom teeth becoming smaller, they can still cause problems because the human jaw has also become smaller with time, which could be because as we learned to cook, our food became softer and required less power to chew.
Sept 29, 07: It's not just people who find it hard to get going in the morning. Cockroaches don't like mornings either, according to U.S. researchers. They found dramatic variations in a cockroach's learning ability throughout the day. In the morning, the insects couldn't learn a new task, but in the evening, something kicked in.
. . "This study was a surprise from the beginning to the end --the fact that cockroaches could be trained, even though you would not generally say they are a high IQ creature, and the impact that their body clocks had on their ability to learn."
Sept 27, 07: Scientists who pulled DNA from the hair shafts of 13 Siberian woolly mammoths said it may be possible to mine museums for genetic information about ancient and even extinct species. They were able to sequence a DNA sample taken from mammoth hair that had been "in somebody's drawer for 200 years", and one that was at least 50,000 years old.
. . The DNA was found in the hair shaft, not the roots of the hair, and it was better preserved than samples taken from bone, Miller said. It also was less likely to be contaminated with bacterial DNA than other DNA samples taken from ancient creatures. "The hair specimens have been stored for the past 200 years at room temperature."
. . The oldest verified DNA comes from the bones of Neandertal humans who lived in Europe 30,000 to 40,000 years ago, and from a 40,000-year-old cave bear bone. Scientists have found preserved tissue in 68 million-year-old dinosaur bones but have not yet reported finding intact DNA in the samples.
Sept 27, 07: Oxygen, key to life on Earth today, began to appear on the planet millions of years earlier than scientists had thought, new research indicates. An analysis of a deep rock core from Australia indicates the presence of at least some oxygen 50 million to 100 million years before the great change when the life-giving element began rising to today's levels, according to two papers.
. . Previously, the earliest indications of oxygen had been from between 2.3 billion and 2.4 billion years ago when the "Great Oxidation Event" occurred. The cause of the event is still not known, but before that the atmosphere was dominated by methane and ammonia. Today oxygen makes up about 21%.
. . The discovery of traces of early oxygen was made in a study of a 3,000-foot-long rock core extracted in western Australia. "We seem to have captured a piece of time before the Great Oxidation Event during which the amount of oxygen was actually changing —-caught in the act, as it were."
Sept 25, 07: Like hunter-gatherers in the jungle, modern humans are still experts at spotting predators and prey, despite the developed world's safe suburbs and indoor lifestyle, a new study suggests.
. . The research reveals that humans today are hard-wired to pay attention to other people and animals much more so than non-living things, even if inanimate objects are the primary hazards for modern, urbanized folks.
. . The researchers say the finding supports the idea that natural selection molded mechanisms into our ancestors' brains that were specialized for paying attention to humans and other animals. These adaptive traits were then passed on to us.
Sept 25, 07: From post-coital cannibalism to love at first sight, the sex life of the African jumping spider is full of surprises, according to a new study. But none is more unexpected than this, say researchers who studied the blood-gorging Evarcha culicivora up close and personal: while virgin females are attracted to meatier mates, a bit of experience sees them switch to smaller partners.
. . In this and other ways, the jumping spider, native to East Africa, is in a class of its own when it comes to sex. For starters, both males and females play a roughly equal role in choosing partners, an aberration in the eight-legged world of Arachnida.
. . That equal opportunity behavior extends to two-way cannibalism as well, with males consuming their loved ones only slightly more often as the reverse. For spiders that go in for that sort of thing, females gobbling up their sex partners is the norm.
. . Another finding that surprised a team of researchers led by Simon Pollard, a biologist at the Cantebury Museum in Christchurch, New Zealand, was that E. culicivora --armed with eye-sight "unrivalled by other animals in their size range"-- picks its partner based on looks and size alone.
. . And here is where things get strange. Female adult African jumping spiders vary in size between three and six millimeters, while males range between four and seven, giving rise to the possibility of larger males mating with smaller females and vice versa.
. . In a series of laboratory experiments, Pollard showed that in three of four possible scenarios, an individual E. culicivora preferred a partner with an extra millimeter or two on its frame. Virgin females, along with both experienced and inexperienced males, were all more than twice as likely to opt for a meatier mate.
. . But females that had copulated once before saw things differently: two out of three made a bee-line for the smallest male in sight. "It is as though females start out prepared to take the risk in choosing larger males", knowing they may be eaten as a post-sex snack, Pollard notes in the study. "And then, once mated, they become less inclined to take the risk again."
. . The African jumping spider feeds mainly on small lake flied and blood-gorged female mosquitos, which means that vertebrate blood is an important part of their diet.
Sept 22, 07: Scientists have discovered a real gender-bender of a bug, a species in which most females impersonate males. Past research had already revealed the male bugs possessed fake female genitalia.
. . "We ended up uncovering a hotbed of deception", said evolutionary biologist Klaus Reinhardt at the U of Sheffield in England. "Nothing like this exists anywhere else in the animal kingdom." Reinhardt and his colleagues investigated remote and dangerous bat caves in East Africa for the bloodsucking African bat bug (Afrocimex constrictus), a close relative of the bed bug. The bats were reportedly hosts for Ebola and other lethal viruses.
. . Sex among bat bugs (as with bed bugs) is violent. During copulation, males of these species pierce the abdomens of their mates with their genitals and ejaculate directly into their blood.
. . Unlike bed bugs, male African bat bugs have bogus female genitals -—a fact the scientists freely call "bizarre." Past research found they mate with each other as well as with females. Although the sham genitals are convincingly intricate, they do not have a covering over them as real female genitals do.
. . Surprisingly, the scientists have now discovered that female African bat bugs practiced gender-bending also by impersonating males. Only one out of six females possessed conventional female genitals, while the rest had genitals resembling the fakes seen on males.
. . By masquerading as males, females enjoy less sexual attention. Given that sex leads to wounding in these bugs, Reinhardt and his colleagues suggest avoiding the trauma of sex makes sense. Indeed, the researchers discovered females that impersonated males had far less fewer than more conventional females.
. . It also remains a mystery as to why males possess sham female genitals. Scientists think the males might genitally stab any adult bat bug, so one conjecture as to why males evolved bogus female genitals involves guiding stabs to relatively safe parts of the anatomy.
. . "Our results suggest that the battle of the sexes is a very powerful evolutionary force which can result in very bizarre adaptations", Reinhardt said.
Sept 20, 07: Alex was best known to the public as the amazing talking parrot. Way beyond "Polly want a cracker", this bird knew more than 100 words and could hold a decent conversation. Scientists in particular mourn his passing, not just because Alex was an excellent linguist, but also because he rattled our cage. Here was a bird that in many ways did better at language than chimps. What did that say about human evolution?
. . And if Alex was as good as an ape for modeling human evolution, then other animals might be worth looking at as well. Scientists owe a great debt to Alex, and we'd all like to say we're sorry for being such snobs for so long.
Sept 20, 07: The vicious little dinosaur Velociraptor was a feathered fiend, according to scientists who found evidence of quills on this well-known meat-eater's forearm. This Velociraptor's remains date back 80 million years to the Cretaceous Period.
. . Paleontologists said a forearm bone of Velociraptor found in Mongolia's desolate Gobi desert retained structures, or quill knobs, where a series of feathers were anchored to the bone with ligaments. No actual fossils of the feathers were found, but the researchers said quill knobs would not exist without feathers. They are present in many bird species alive today.
. . The researchers said the discovery is a further indication that many carnivorous dinosaurs, and not just the very smallest, possessed feathers. They added that the presence of feathers, which among other qualities provide insulation, was another sign that these may have been warm-blooded animals.
. . Scientists have found, particularly at one site in China, fossils of small carnivorous dinosaurs and others preserved with feathers. Some scientists think larger predators, perhaps even Tyrannosaurus rex, may have had feathers or downy "protofeathers", at least as juveniles.
. . Scientists believe birds, which first appeared roughly 150 million years ago, evolved from small feathered carnivorous dinosaurs. While Velociraptor was a very close relative of birds, it could not fly. So why did it have feathers?
. . Feathers may have been useful for display as seen in birds like the peacock, for temperature control, to shield nests or to help maneuver while running, the researchers said. It was about 1 meter tall. Turner said a Velociraptor was about the size of a large condor. It had short forelimbs, compared to a modern bird, the researchers said, indicating it would not have been able to fly, even though it had feathers.
. . "The more that we learn about these animals, the more we find that there is basically no difference between birds and their closely related dinosaur ancestors like Velociraptor", Mark Norell of the American Museum of Natural History, another researcher in the study, said. "Both (groups) have wishbones, brooded their nests, possess hollow bones, and were covered in feathers."
. . Velociraptor is thought to have been a fast and deadly bipedal hunter, preying on small and medium-sized dinosaurs as well as lizards, mammals and probably any other animal that had the bad fortune of looking like dinner. Aside from its sharp teeth, its most potent weapon was a large sickle-shaped claw on each foot that scientists think was used to slash open victims much like a switchblade.
. . Perhaps the most famous fossil of a Velociraptor shows it in the act of attacking a plant-eating dinosaur called Protoceratops. Scientists think the attack occurred on a Mongolian sand dune that collapsed during the fight, preserving the struggle for eternity.
Sept 19, 07: The earliest-known human ancestors to migrate out of Africa possessed a surprising mix of human-like and primitive features, according to scientists who studied remains dug up at a fossil-rich site in the former Soviet republic of Georgia. The scientists described remains of three adults and one adolescent dating from about 1.77 million years ago.
. . The spines and lower limbs found at the Dmanisi site appear very much like modern humans, suggesting these individuals, which walked fully upright, were highly capable of long-distance treks, the researchers said. But other aspects of the skeletons had more archaic characteristics. The arms were more like australopithecines than people, and the primitive skulls encased relatively small brains. Their simple stone tools also are less advanced than one might have expected
. . Also found at the site were remains of other animals that lived alongside these human ancestors, including saber-toothed cats.
. . Evidence at the site, the researchers said, suggested that these humanoid creatures were meat eaters, either hunting for their dinner or scavenging carcasses killed by other animals. They were relatively small, about 4.9 feet tall.
. . "Before these finds, it was considered that the humans who left Africa should have had completely human-like bodies, more human-like proportions and bigger brains", Lordkipanidze said.
. . Harvard U anthropologist Daniel Lieberman, who wrote a commentary accompanying the study, said the human evolutionary events unfolding at about the time these individuals lived were very important.
Sept 19, 07: The fossilized remains of six young dinosaurs found together in a "nursery" at a site in China show these animals had started forming social groups much earlier than previously thought, scientists said. The find sheds light on the life of the beaked dinosaur Psittacosaurus and on the origins of social behavior in its descendents, including the horned Triceratops, said Paul Barrett.
. . They found the remains in the Yixian Formation, an area in northeast China rich in fossils of primitive mammals, birds and feathered dinosaurs. Psittacosaurus was a small herbivore that lived in China, Mongolia, Siberia and Thailand about 130 million to 100 million years ago. It was an early relative of Triceratops and Protoceratops.
. . The largest of the young dinosaurs, probably aged one-and-a-half to three-years old when they died, measured about 50 cm from the tip of the nose to its tail and weighed about a kilogram (2 lbs). Adults were about 2 meters long and weighed up to 30 kg.
. . The age range of the fossils suggested they came from different eggs, laid by different parents, he said. The remains formed a nursery with babies from at least two different parents, he added. The baby dinosaurs were probably killed in a volcanic mudflow, but the way the researchers discovered them, lying side by side, indicates they lived in a herd, Barrett said. "These animals had left the nest and were already hanging out with each other", he said.
Sept 17, 07: Lefties have been bouncing back in recent decades, following a decline in the beginning of the 20th century, a new study shows.
. . While lefties currently make up about 11% of the population, earlier studies found only 3% of those born in 1900 were left-handed. These claims led Ian Christopher McManus of the University College London and his colleagues to learn more about this change.
. . "Left-handedness is important because more than 10% of people have their brains organized in a qualitatively different way to other people", McManus said. "That has to be interesting. When the rate of a [variable trait] changes, then there have to be causes, and they are interesting as well."
. . Researchers looked at a series of films made between 1897 and 1913 by early filmmakers. They identified 391 arm-wavers in the films and compared the number of lefties and righties in the old movie to a more modern "control group" formed by searching for "waving" with Google Images. About 15% of the people in the old films waved with their left hand, compared to 24% of lefty wavers in the Google search. The researchers compared these results to previous studies of handedness in writing and found that left-handed waving is more common than left-handed writing.
. . After correcting for this bias, the researchers found that "the earlier Victorian rates of left-handedness are broadly equivalent to modern rates, whereas rates then decline, with the lowest values for those born between about 1890 and 1910." The lefties in the Victorian films were typically older, which rules out the possibility of higher rates of mortality among lefties.
. . The most likely reason that lefties dropped in numbers at the turn of the 20th century was possible social influence brought about by universal education and the industrial revolution. These two factors would have forced lefties into the spotlight as they learned to write in the classroom or clumsily used machines built for right-handers. "We do have evidence that around the turn of the 20th century left-handers had fewer children than right-handers."
Sept 17, 07: Honeybees can smother their enemies to death by swarming them, European researchers reported. The discovery means that bees have three ways of dispatching their enemies -- by stinging, which for a bee means suicide; by raising the other creature's body temperature, or thermo-balling; and by asphyxiation. "Here, for the first time, we detail an amazing defense strategy, namely asphyxia-balling, by which Cyprian honeybees mob the hornet and smother it to death."
. . It had been known that Asian honeybees kill their hornet enemies by thermo-balling. A swarm of bees will cover the unfortunate insect, raising its body temperature to lethal levels. But the Cyprian honeybees do not raise temperatures to deadly levels when they mob their hornet foes, which prey on bees and their larvae.
. . They noticed that the bees press on the insects' abdomens, so they set up an experiment to see if perhaps the bees were suffocating the hornets. Insects breathe through openings in their exoskeletons called spiracles. These are covered by structures known as tergites when air is released. Using tiny tweezers, the scientists propped the tergites open with teensy pieces of plastic. "It took much longer for honeybees to kill hornets equipped with plastic blocks than those without", the researchers wrote.
Sept 13, 07: Neandertals probably fell victim to taller and superior Cro-Magnons rather than catastrophic climate change, researchers said.
. . Using a new method to calibrate carbon-14 dating, the international team found the last Neandertals died at least 3,000 years before a major change in temperatures occurred. This suggests either modern humans or a combination of humans and less severe climate change caused the species' demise some 30,000 years ago, said Chronis Tzedakis, a paleoecologist at the U of Leeds.
. . Despite their image as club-carrying hairy brutes, research suggests they were expert tool-makers, used animal skins to keep warm and cared for each other. Most researchers believe Neandertals survived in Europe until the arrival of fully modern humans about 30,000 years ago but controversial findings last year indicated they might have survived to as recently as 24,000 years ago.
. . The team found that even though temperatures were fluctuating 30,000 years ago, the swings were not severe and similar to climate changes Neandertals previously withstood. Additionally, none of the dates ranging from 24,000 to 32,000 years ago that the researchers tested corresponded with any big climate changes.
Sept 11, 07: A South African fossil suggests pelycosaurs --intermediates between reptiles and mammals that lived in the Permian Period before the rise of dinosaurs-- may have been caring parents 260 million years ago, scientists said.
. . They found a fossilized group consisting of an adult pelycosaur and four juveniles arranged in a family group. The youngsters appear to be siblings. At 260 million years old, this family predates the previously known oldest fossil evidence of parental care in terrestrial vertebrates by 140 million years.
Sept 11, 07: Pilfered fruit brazenly plucked under the farmer's gaze may be the secret to stolen love, at least for wild male chimpanzees and their consorts, British researchers said.
. . Wild chimps in West Africa pinch fruits from local farms to impress the lady chimps, and it seems to pay off, said Dr. Kimberley Hockings. "The adult male who shared most with this female engaged in more consortships with her and received more grooming from her than the other adult males, even the alpha male." The favored fruit was typically papaya, which is large and easy to share, but oranges and pineapple also scored.
. . Hockings said possessing a desirable food item may draw positive attention to an individual and help establish or cement an adult male chimpanzee's relationships. "Crop-raiding adult males may be advertising prowess to other group-members", she said.
. . Hockings said the males showed signs their risky behavior was nerve-racking, as evidenced by rough self-scratching, a behavior pattern involving large movements of the arm that suggests anxiety. Rough self-scratching levels were more than 4 times higher when adult male chips stole and ate cultivated food compared with wild food. Nevertheless, stolen foods were shared much more frequently than wild plant foods.
Sept 11, 07: It's official --the godwit makes the longest non-stop migratory flight in the world. A bird has been tracked from its Southern Hemisphere summertime home in New Zealand to its breeding ground in Alaska --and back again.
. . The bar-tailed godwit, a female known as E7, landed in New Zealand this past weekend after taking a week to fly 11,500km from Alaska to New Zealand. Unlike seabirds, which feed and rest on long journeys, godwits just keep going.
Sept 11, 07: Some crucial ingredients for life on Earth may have formed in interstellar space, rather than on the planet's surface. A new computer model indicates clouds of adenine molecules, a basic component of DNA, can form and survive the harsh conditions of space, and possibly sprinkle onto planets as the stars they orbit travel through a galaxy. "There may be only a few molecules of adenine per square foot of space, but over millions of years, enough could have accumulated to help make way for life."
. . Adenine is one of four "letters" of DNA's alphabet used to store an organism's genetic code. Glaser said the idea that large, two-ringed organic molecules like adenine formed in space may seem outrageous, but current evidence leaves the possibility wide open.
. . In computer simulations of the cold vacuum of space, Glaser and his colleagues found that hydrogen cyanide (HCN) gas can build adenine. Like pieces in a set of tinker toys, hydrogen cyanide serves as adenine's building blocks; the small molecules bond together into chains and, with a little wiggling, eventually assemble into rings.
. . Although adenine's first ring needs a tiny energy boost from starlight to form, Glaser said the second ring of the molecule self-assembles without any outside help. "When you want to have a reaction, you usually need to heat it up," Glaser said. "It's remarkable to find a reaction that doesn't require activation energy. If you do this reaction in space, this is a huge advantage because it takes a long time for a molecule to be hit by a piece of light."
. . Glaser said adenine's ringed shape helps it absorb and release any excess energy without breaking apart, making it stable enough to form concentrated clouds that planets can drift through.
. . For Glaser and his team's idea to be widely supported, however, adenine needs to be detected in the deep space clouds, Lazcano said. "The likelihood of detection is very small, but it's still possible," he said. "If astronomers can better eliminate background noise, I think we'll have equipment sensitive enough to detect adenine dust clouds."
Sept 11, 07: Two molar teeth of around 63,400 years old show that Neandertal predecessors of humans may have been dental hygiene fans. The teeth have "grooves formed by the passage of a pointed object, which confirms the use of a small stick for cleaning the mouth," Paleontology Professor Juan Luis Asuarga told reporters.
Sept 11, 07: A celebrated parrot who cooperated with scientists for three decades as they conducted research that determined the species' intellect could match that of a 5-year-old human has died.
Sept 10, 07: The mystery behind the tree rubbing antics of North America's grizzly bears may at last have been solved. A few select trees are used by grizzlies to perform strange rubbing rituals, but for years the reasons for this behaviour have baffled ecologists. Now, a study suggests that male grizzlies seeking mates are marking the trees to communicate with other males --possibly to dodge deadly bear battles.
. . The cameras revealed that large adult male bears were marking and carefully inspecting the rub trees, but female bears were ignoring the trees. The satellite telemetry showed that the grizzlies were moving around the area in large loops, marking trees along the way, while looking for females.
. . "For a large grizzly bear, the only real source of mortality is other big bears, so lots of strategies are adopted to reduce the likelihood of having to fight. "If one recognizes the other from the scent marks on the rub trees in the area, he knows he's in for a tough fight --he's on the other guy's patch, so to speak-- so it might be better to back away than make a serious challenge. "When two males meet, the more information they have, the better for both of them."
. . The digital cameras also recorded that the rub trees were occasionally visited by young cubs that were being chased away by a male courting their mother. Male bears can sometimes kill a female's cub in order to mate with her, explained Dr Nevin, and the cubs might be visiting the trees for self-protection. "In the animal world, related individuals recognise each other by the fact that they smell a bit like each other, so perhaps the cubs are seeking security by trying to smell like the males who have just chased them off."
Sept 10, 07: When we read, our eyes lock on to different letters in the same word instead of scanning a page smoothly from left to right as previously thought, researchers said. Using sophisticated eye tracking equipment, the team looked at letters within a word and found that people combined parts of a word that were on average two letters apart. [Waitaminute! This musta evolved for some reason other than reading, because we haven't had a large population doing that for that long.]
. . The findings could lead to better methods of teaching children to read and offer remedial treatments for those with reading disorders such as dyslexia.
. . Over the past 40 years, scientists have studied eye movements and reading, with a general consensus that people look at the same letter within a word with both eyes, Liversedge said. To test this, Liversedge and colleagues measured the reflections of a low-intensity infrared beam shone into a volunteer's eye when reading. This allowed the researchers to pinpoint exactly where the eye had fixated on a word.
. . Then they ran further tests to see why people did not have double vision from picking out individual letters and found that the brain fuses the two signals that come in from the different eyes into one clear image.
. . "It had always been assumed that both eyes moved in perfect harmony and you looked at a word with just one fixation," he said. "Because of this assumption scientists looking at reading behavior have just measured one of the eyes because they assumed the eyes were doing the same thing."
Sept 8, 07: Scientists have digitally crash-tested the predator performance of two Australian icons --the feral dingo dog and the extinct Tasmanian "tiger".
. . The team built sophisticated computer models of the animals' skulls to compare their feeding behavior. The study showed that although the tiger was the bigger, more efficient biter, the dingo was better equipped to deal with prey that struggles.
. . It has long been suggested that the feral dog Canis lupus dingo out-competed the tiger (Thylacinus cynocephalus) for food, and was a major factor in pushing the marsupial carnivore off mainland Australia.
. . The new analysis, which simulates the bite forces and stress patterns applying to dingo and thylacine skulls in the act of killing, confirms there would have been substantial overlap in their choice of prey.
. . "What this study suggests is that the thylacine had a much more restricted range of prey", explained Dr Stephen Wroe. "The dingo, on the other hand, is adept at taking anything from invertebrates through to kangaroos. The dingo can also be a social hunter and it's most unlikely that the thylacine was; and we know that the more specialized an animal is, the more vulnerable it is."
. . The study demonstrates, the team says, that despite being armed with a more powerful and efficient bite and having larger energy needs than the dingo, the thylacine would have been restricted to eating relatively small prey. On the other hand, the dingo's stronger head and neck anatomy allows it to subdue large prey as well, they add.
. . The dingo was introduced by humans to mainland Australia little more than 4,500 years ago and spread rapidly across the continent - only failing to reach Tasmania because rising sea levels had inundated the Bass Strait some 6,000 years earlier.
Sept 6, 07: Toddlers may act up like little apes, but researchers who compared the species concluded a 2-year-old child still has the more sophisticated social learning skills.
. . In one test, preschoolers who wanted a toy hidden in a trick tube intently copied a scientist's movements to retrieve the prize. Chimps watched the lesson, but then mostly tried to smash or bite open the tube. When it came to simple math, however, the apes seemed to know more than the youngsters, apparently "adding" how many tasty raisins researchers had hidden.
. . This conflicts with other research that suggests the other great apes are quite good at social learning, too. In fact, a second study in the same journal suggests chimps and monkeys have some capacity to infer someone's intentions by their actions. That is pretty complex, human-like thinking.
. . In that work, the animals sought out food containers that a researcher had grasped purposefully, not just tapped, or a container that he had touched with his elbow when his hands were full, but not one elbowed when his hands were empty. The chimps and monkeys expected someone to behave rationally and adjusted their own actions accordingly, according to the lead researcher.
. . Chimps and preschoolers could tell at a glance which dish contained a few more raisins. But when the dishes were covered and extra raisins dropped in, the apes kept better track of which dish had more.
Sept 5, 07: Moray eels, those snake-like predators that lurk in coral reefs, use a second set of jaws to pull prey back into their throats with deadly efficiency, researchers said.
. . Biologists have known for some time that moray eels have a second set of jaws, known as pharyngeal jaws, as do many other bony fish. But until now, biologists had never seen them put to such unique use. "They spotted this outrageous behavior of the pharyngeal jaw thrusting way forward into the mouth, which was not suspected before."
. . Rita Mehta and colleagues at the U of California Davis discovered the moray's special feeding ability through high-speed digital cameras, that captured the second jaw as it jutted forward while feeding. When not in use, the moray's extra set of jaws rest behind the eel's skull. When in use, they move almost the length of the animal's skull.
. . Mehta and Wainwright suspect moray eels may have evolved this fierce feeding method through hunting in tight spaces, such as the crevices of coral reefs. In the wild, moray eels can reach 10 feet in length.
Sept 5, 07: People are less alike than scientists had thought when it comes to the billions of building blocks that make up each individual's DNA, according to a new analysis. "Instead of 99.9% identical, maybe we're only 99% (alike)", said J. Craig Venter, an author of the study —-and the person whose DNA was analyzed for it. Several previous studies have argued for lowering the 99.9% estimate. Venter says this new analysis "proves the point."
Sept 5, 07: A gene that keeps mice and fruit flies lean might offer a way to prevent obesity and diabetes in people, U.S. researchers said on Tuesday. The gene, discovered more than 50 years ago in fruit flies, makes mice fat when tweaked one way and thin when manipulated another way. That suggests it would work this way in humans, because mice and people are both mammals.
. . For years, researchers seeking to explain why people are prone to get fat have used the "thrifty gene" hypothesis. Early humans who survived famine after famine were those who could easily store a layer of fat for the lean times.
. . While obesity is likely to be caused by a variety of genes and their interactions with behavior and the environment, this one is a good candidate for study. The gene, called adp for adipose, was discovered by Winifred Doane, while she was studying infertility in fruit flies as a graduate student at Yale U.
. . Doane, now a professor emeritus of zoology at Arizona State U, stressed the flies by starving them and putting them in a desiccator to simulate extreme conditions. Those that lacked a working copy of the adp gene survived, despite starvation and dry conditions.
. . Finding that it works in the same way in mice and fruit flies is important because it means the gene is conserved, or has evolved from "lower" to "higher" animals. Doane said the gene appears to be a regulatory gene, meaning it controls the activity of other genes.
. . Graff and other experts say one place to start looking for humans who have mutant versions of the gene would be Pima Indians from the southwestern US and Australian aborigines, both of whom have high rates of type-2 diabetes and obesity when they begin living Western lifestyles.
. . In humans, adp is in a region of the genome that is already linked to obesity and diabetes, Graff said. And it is not an all-or-nothing gene, at least not in mice tested in the lab. "This is a volume control -- not on and off. As you get less and less function of protein, you get fatter and fatter, and as you get more and more, you get skinnier and skinner", Graff said. "People who want to fit in their jeans might someday be able to overcome their genes."
Sept 3, 07: Very different fossils are being hung on the human family tree on separate branches but at the same height. And once again, we have to reconsider the path of human evolution.
. . But should we be all that surprised? We want the first bipedal humans to stay out of the trees, but their curved hand bones suggest they spent time swinging in the canopy like apes; we want brain size to increase in lock step with tool use, but tools appear before big brains; we want an orderly diaspora out of Africa and across the globe by culturally armed early humans, but it looks like people kept leaving all the time in fits and starts that don’t correlate with anything; and we want the last 200,000 years of human evolution, the time when modern Homo sapiens appeared, to make some kind of sense, but it doesn't.
Sept 3, 07: An international team of scientists have discovered the first gene that influences a person's height.
Sept 1, 07: A monstrous network of sheet-like webs covering several acres has been spun over trees in this state park 80 kms east of Dallas, baffling scientists who say it is an almost-unheard-of occurrence in the region. "The dominant spiders here seem to be long-jawed spiders but this is unusual. Social spiders build communal nests in the tropics but the longjaws are not social", said Mike Quinn, a Texas state insect biologist.
Aug 29, 07: Ancient orchid pollen found attached to a bee trapped in amber suggests the "supermodels of the plant world" were blooming at the time of the dinosaurs. The discovery indicates that orchids arose between 76 and 84 million years ago, making them far older than experts had previously thought. Experts used the fossil pollen grains to estimate the ages of major branches of orchids living today.
. . Despite being the most diverse plant group on Earth, orchids are rare finds in the fossil record. The authors of the Nature paper describe a mass of orchid pollen found stuck to the body of an extinct bee that lived 15-20 million years ago.
. . Dating the fossil allowed lead researcher Santiago Ramirez to calibrate a "molecular clock" which uses mutations, or changes, in the plants' DNA to estimate the time of divergence between living organisms. By building a "family tree" of orchids, the scientists could move back in time to see when the species first appeared, as well as where and how it spread. They found that the most recent common ancestor of all modern-day orchids lived in the twilight of the dinosaurs, during the Late Cretaceous period.
Aug 22, 07: When interacting with their infants, female rhesus monkeys use special vocalizations similar to the "baby talk" used by human mothers to get an infant's attention, U of Chicago researchers report.
. . "Motherese is a high pitched and musical form of speech, which may be biological in origin." "The acoustic structure of particular monkey vocalizations, called girneys, may be adaptively designed to attract young infants and engage their attention.
. . When a baby was present, there was a significant increase in the amount of grunts and girneys among the adult females. "The calls appear to be used to elicit infants' attention and encourage their behavior. They also have the effect of increasing social tolerance in the mother and facilitating the interactions between females with babies in general. Thus, the attraction to other females' infants results in a relatively relaxed context of interaction where the main focus of attention is the baby", the researchers wrote.
Aug 22, 07: Having trouble persuading your child to eat broccoli or spinach? You may have only yourself to blame. According to a study of twins, neophobia —-or the fear of new things-— is mostly in the genes.
. . They asked the parents of 5,390 pairs of identical and non-identical twins to complete a questionnaire on their children's' willingness to try new foods. Identical twins, who share all genes, were much more likely to respond the same way to new foods than non-identical twins, who like other siblings only share about half their genes. Researchers concluded that genetics played a greater role in determining eating preferences than environment, since the twins lived in the same household. Wardle said food preferences appear to be "as inheritable a physical characteristic as height."
. . Unlike nearly every other phobia, neophobia is a normal stage of human development. Scientists theorize that it was originally an evolutionary mechanism designed to protect children from accidentally eating dangerous things — like poisonous berries or mushrooms.
. . Neophobia typically kicks in at age 2 or 3, when children are newly mobile and capable of disappearing from their parents' sight within seconds. Being unwilling to eat new things they stumble upon may turn out to be a lifesaver.
. . While most children grow out of the food fussiness by age 5, not all do. For parents of particularly picky eaters, experts encourage them not to cave in when their children throw food tantrums.
. . Other taste-related traits —-like the ability to taste bitterness-— are also inherited. Scientists have already identified the gene responsible, and have found that approximately 30% of Caucasians lack the gene and cannot taste bitterness.
Aug 22, 07: A new study has measured just how long cats can remember certain kinds of information -—10 minutes. The research was designed primarily to compare cats' working memory of their recent movements with their visual memories, and found that cats remember better with their bodies than their eyes when they have encountered an object placed in their path. Research with horses and dogs has shown similar results.
Aug 22, 07: Researchers working in Ethiopia have unearthed the fossils of a 10-million-year-old ape, a discovery they say suggests that humans and African great apes may have split much earlier than thought. They said Chororapithecus abyssinicus represents the earliest recognized primate directly related to modern-day gorillas, chimpanzees and bonobos. "The human fossil record goes back six to seven million years, but we know nothing about how the human line actually emerged from apes."
. . "Chororapithecus indicates that a reconsideration of this assumption is needed", the researchers said. "In fact, if the orang line was present in Africa prior (to the) first migration of Miocene (some 23-25 million years ago) apes from Africa to Eurasia, then the human-orang split could have easily have been as old as 20 million years ago."
Aug 21, 07: The smallest dinosaur could reach speeds of 64 kph and even the lumbering Tyrannosaurus rex would have been able to outrun most modern-day sportsmen, according to research.
. . Scientists using computer models calculated the top speeds for five meat-eating dinosaurs in a study they say can also illustrate how animals cope with climate change and extinction. The five dinosaurs that varied in size from the 3-kg Compsognathus to a six-ton Tyrannosaurus. The velociraptor, whose speed and ferocity was highlighted in the film "Jurassic Park", reached 24 mph while the T-rex could muster speeds of up to 18 mph.
. . The smallest dinosaur --the Compsognathus-- could run nearly 40 mph, about 5 mph faster than the computer's estimate for the fastest living animal on two legs, the ostrich. A top human sprinter can reach a speed of about 25 mph.
Aug 21, 07: In order to truly understand forest ecology and the responses of forests to environmental threats such as global warming, we must understand how the entire forest works –-from root tip to tree top.
. . We now know that the canopy holds organisms that interact with one another and their physical environment in ways that can have impacts on the entire forest. Some plant and animal species live their entire lives on the branches and trunks of trees without ever touching the forest floor.
. . When these “plants growing on plants” die and decompose, they generate a layer of soil up to 10 inches thick that rests on canopy branches. This soil provides a habitat for a huge diversity of insects, earthworms, and spiders, which in turn, provide critical sources of food for birds and tree-dwelling mammals. Thus, the seemingly disconnected world of the forest canopy performs essential functions for the whole ecosystem.
. . As many as 70 moss species may live in a single tree, and over 150 moss species may live in a single forest stand. Analyses conducted by the US Geological Survey confirmed that my canopy samples were composed of ash from the 1980 eruption of Mt St Helens. This means that this ash had persisted on these thin canopy tree limbs, 200 feet above the forest floor, for 27 years of wind, rain, and exposure.
. . These canopy mosses, like most “plants growing on plants”, meet their nutrient needs solely by absorbing minerals dissolved in rainwater rather than by absorbing minerals from the soil or branches beneath them.
. . The soil depth indicated that the soil was accumulating at a rate of up to four tenths of an inch per year. This was important because the speed of soil accumulation in the canopy had never before been measured and exceeded all previously projected rates of canopy soil dynamics.
Aug 21, 07: Egyptian archaeologists have found what they said could be the oldest human footprint in history in the country's western desert, the Arab country's antiquities' chief said. "This could go back about two million years", said Zahi Hawass, the secretary general of the Egyptian Supreme Council of Antiquities.
. . Archaeologists found the footprint, imprinted on mud and then hardened into rock, while exploring a prehistoric site in Siwa, a desert oasis. Scientists are using carbon tests on plants found in the rock to determine its exact age.
Aug 20, 07: Around the world, a handful of scientists are trying to create life from scratch, and they're getting closer. Experts expect an announcement within three to 10 years from someone in the now little-known field of "wet artificial life."
. . "It's going to be a big deal and everybody's going to know about it", said Mark Bedau, chief operating officer of ProtoLife of Venice, Italy, one of those in the race. "We're talking about a technology that could change our world in pretty fundamental ways —-in fact, in ways that are impossible to predict." That first cell of synthetic life —-made from the basic chemicals in DNA-— may not seem like much to non-scientists. For one thing, you'll have to look in a microscope to see it.
. . Bedau figures there are three major hurdles to creating synthetic life:
. . • A container, or membrane, for the cell to keep bad molecules out, allow good ones, and the ability to multiply.
. . • A genetic system that controls the functions of the cell, enabling it to reproduce and mutate in response to environmental changes.
One of the leaders in the field, Jack Szostak at Harvard Medical School, predicts that within the next six months, scientists will report evidence that the first step —-creating a cell membrane-— is "not a big problem." Scientists are using fatty acids in that effort.
. . Szostak is also optimistic about the next step —-getting nucleotides, the building blocks of DNA, to form a working genetic system. His idea is that once the container is made, if scientists add nucleotides in the right proportions, then Darwinian evolution could simply take over. "We aren't smart enough to design things, we just let evolution do the hard work and then we figure out what happened", Szostak said.
. . "When these things are created, they're going to be so weak, it'll be a huge achievement if you can keep them alive for an hour in the lab", he said.
Aug 18, 07: U of California anthropologist Tim Weaver and colleagues compared skull measurements of 2,500 humans and 20 Neandertals, then contrasted the results with genetic data from another 1,000 people. The result of all the number-crunching? Natural selection doesn't appear to have anything to do with the difference.
. . "We conclude that rather than requiring special adaptive accounts, Neandertal and modern human crania may simply represent two outcomes from a vast space of random evolutionary possibilities."
Aug 18, 07: An international team has discovered that under the right conditions, particles of inorganic dust can become organized into helical structures. These structures can then interact with each other in ways that are usually associated with organic compounds and life itself. The right conditions are found in a plasma --that fourth state of matter beyond solid, liquid and gas, in which electrons are torn from atoms leaving behind a miasma of charged particles.
. . In a computer model of inorganic particles in plasma, researchers from the Russian Academy of Science, the U of Sydney and the Max-Planck Institute for Extraterrestrial Physics watched plasma-state inorganic dust organize itself, twisting into strands that look and act a bit like DNA. They can, for instance, divide, or bifurcate, to form two copies of the original structure. These new structures can also interact to induce changes in their neighbours and they can even evolve into yet more structures as less stable ones break down, leaving behind only the fittest structures in the plasma.
. . "These complex, self-organized plasma structures exhibit all the necessary properties to qualify them as candidates for inorganic living matter", says Tsytovich, "they are autonomous, they reproduce and they evolve."
. . Where are plasma-friendly conditions found? In space ... and on earth, where lightning strikes. It's a plausible mechanism for the origin of terrestrial life.
Aug 16, 07: Whose offspring do better, families in privileged circumstances or those struggling to keep food in the kids' mouths? For a type of Australian bird called the superb fairy-wren, it turns out it doesn't make any difference.
. . Researchers found that wren moms with little help lay larger eggs, getting their chicks started off on the right foot. But mother wrens who have a lot of helpers around don't have to bother; they produce smaller eggs, knowing there will be plenty of birds bringing home food for the little ones. Both groups of chicks did equally well, even though those that lived in cooperative situations got 19% more food than those fed only by their parents.
. . They needed it. Those chicks were hatched from eggs that were 5.3% smaller than those of parents without help, and their eggs contained 12% less fat and 13% less protein, "suggesting that mothers invest less energy in their eggs when breeding in the presence of helpers", the scientists reported.
. . The probable reason, they suggested, was that the females breeding in groups were "reducing their own investment in reproduction to save resources for future breeding attempts."
Aug 16, 07: Life almost undoubtedly began in space, and specifically in the hearts of comets, rather than on Earth, a new study claims.
. . Chandra Wickramasinghe, an astrobiologist at Cardiff U in the United Kingdom, and his team say their calculations show that it is one trillion trillion times more likely that life started inside a slushy comet than on Earth. "The comets and the warm watery clay pools in comets are settings in which the organic molecules are transformed into living structures in comets", Wickramasinghe said. "That transformation is more likely in some comet somewhere in the galaxy than in any small pond on the Earth."
. . Critics say that Wickramasinghe's proposal that life originated in comets which subsequently crashed on our planet-an idea called panspermia-is speculative and not supported by evidence. Cometary missions such as Deep Impact have found evidence for a variety of silicates existing inside comets, but not clay per se, Morrison said.
Aug 16, 07: Crows have shown that two tools are better than one when it comes to problem solving, scientists say. A U of Auckland study has revealed that New Caledonian crows can use separate tools in quick succession to retrieve an out-of-reach snack.
. . The birds were using reasoning that was more commonly seen in great apes and humans, the New Zealand team reported. They use their bills to whittle twigs into hooks and cut and tear leaves into barbed probes that can extract bugs and grubs from crevices.
. . To further test the crows' tool-using talents, scientists set seven wild birds a tricky task. The crows were presented with:
. . * A scrap of meat, which was tucked away, out of reach, in a box;
. . * A small twig, which was too short to reach the food;
. . * And another longer twig, which was long enough to reach the food, but was locked away well out of bill-grabbing range in another box.
. . The birds surprised the scientists with their quick thinking. "The creative thing the crows did was to use the short stick to get the long tool out of the box so that they could then use the long stick to get the meat. What is most amazing is that most of them did this on the first trial. The first time we gave them the problem, six out of seven tried to do the right thing. They took the little tool and they tried to get the big tool out, which we had made quite hard to reach, and four out of the six managed to get the big tool out and then use this to get to the food."
. . This kind of reasoning, added Professor Gray, was commonly seen in humans and possibly in great apes. "It might explain why the New Caledonian crows --out of all the crow species in the world-- only these crows routinely make and use tools", he said.
Aug 13, 07: California ground squirrels have learned to intimidate rattlesnakes by heating their tails and shaking them aggressively. Because the snakes, which are ambush hunters, can sense infrared radiation from heat, the warming makes the tails more conspicuous to them — signaling that they have been discovered and that the squirrels may come and harass them. The tail "flagging" places the snakes on the defensive, he said.
. . The adults have a protein in their blood that allows them to survive the snake venom, and they have been known to attack and injure snakes, biting and kicking gravel at them. Rather, the snakes are looking for immature squirrels, which they can kill and eat.
. . "It's such a new discovery that it leaves a lot of questions", he said. But apparently it isn't just a reflex, because they only do it with rattlesnakes. Confronted by gopher snakes, which can't sense heat, the squirrels wave their tails vigorously, but don't bother to heat them up.
Aug 9, 07: An expedition to a remote forest in the Democratic Republic of Congo has uncovered six new animal species. Conservationists discovered one new bat species, a new rat and two new species each of shrews and frogs. The survey covered one square kilometer of forest. "The block of forest has probably been isolated from the rest of the Congo forest block for about 10,000 years."
. . The region, which is in eastern DR Congo, near Lake Tanganyika, has been off limits to researchers since 1960 because of instability in the area.
Aug 8, 07: Difference in size between males and females seem to be related to monogamy, the researchers said. Primates that have same-sized males and females, such as gibbons, tend to be more monogamous. Species that are not monogamous, such as gorillas and baboons, have much bigger males. This suggests that our ancestor Homo erectus reproduced with multiple partners.
. . The Homo habilis jaw was dated at 1.44 million years ago. That is the youngest ever found from a species that scientists originally figured died off somewhere between 1.7 and 2 million years ago.
Aug 8, 07: Surprising research based on two African fossils suggests our family tree is more like a wayward bush with stubby branches, challenging what had been common thinking on how early humans evolved.
. . The discovery by Meave Leakey, a member of a famous family of paleontologists, shows that two species of early human ancestors lived at the same time in Kenya. That pokes holes in the chief theory of man's early evolution — that one of those species evolved from the other. And it further discredits that iconic illustration of human evolution that begins with a knuckle-dragging ape and ends with a briefcase-carrying man.
. . The old theory is that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became human, Homo sapiens. But Leakey's find suggests those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years.
. . The two species lived near each other, but probably didn't interact, each having its own "ecological niche", Spoor said. Homo habilis was likely more vegetarian while Homo erectus ate some meat, he said. Like chimps and apes, "they'd just avoid each other, they don't feel comfortable in each other's company", he said.
. . There remains some still-undiscovered common ancestor that probably lived 2 million to 3 million years ago, a time that has not left much fossil record, Spoor said.
. . Susan Anton, a New York U anthropologist and co-author of the Leakey work, said she expects anti-evolution proponents to seize on the new research, but said it would be a mistake to try to use the new work to show flaws in evolution theory. "This is not questioning the idea at all of evolution; it is refining some of the specific points", Anton said. "This is a great example of what science does and religion doesn't do. It's a continous self-testing process."
Aug 6, 07: Microorganisms locked in Antarctic ice for 100,000 years and more... came to life and resumed growing when given warmth and nutrients in a laboratory. Researchers led by Kay Bidle of Rutgers U tested five samples of ice ranging in age from 100,000 years to 8 million years.
. . The researchers tested samples of the oldest known ice on Earth and had success at growing bacteria from the younger samples. Microorganisms from the older ice didn't do as well, growing only very slowly. Some of the oldest microorganisms were watched for as long as a year, he said, compared to the week or so it usually takes to culture bacteria.
. . Calling the ice cores "gene popsicles", the researchers found evidence of some the most common bacteria still around, including firmicutes, proteobacteria and actinobacteria.
. . Bidle's researchers found that the DNA in bacteria deteriorates sharply after about 1.1 million years. He said that after 1.1 million years, the size of the DNA gets cut in half. In the oldest ice it consisted of just 210 units strung together. Normally the DNA of the average bacterium has about 3 million units.
. . In addition, there is interest in looking for life on other planets and how long microorganisms might have remained viable under cold, icy conditions on places like Mars. Finally, he added, most of life on Earth consists of microbes. "They live in every possible environment ... so learning about microbes and what they can withstand and what their limits are is important to understanding how the Earth works over long periods of time."
Aug 5, 07: Nectar-feeding bats burn up sugar faster than any other mammals on Earth, scientists believe. The UK-German team found that the creatures began to metabolize nectar within minutes of drinking it. The researchers said the animals needed to extract as much energy as possible from their food because their hovering flight used up so much fuel.
. . Glossophaga soricina are among the smallest mammals known, weighing less than 10g. The nocturnal animals are found across South and Central America and scoop nectar from flowers using their long, thin tongues while hovering, much like hummingbirds do. They can drink up to 1.5 times their body weight in nectar each day.
. . While most animals convert most of the carbohydrates they consume to fats or a type of sugar known as glycogen to save up an energy store, the bats convert them straight to energy to get the maximum boost they can. "Metabolising these sugars immediately as they are consumed saves the costs of converting them to and from storage.
Aug 5, 07: Majestic trees owe a sizeable chunk of their sky-high stature to tiny birds. Birds boost tree height up to 33% by munching on pesky parasites that can literally suck the life out of the tall-growing plants, a new study shows.
. . "More than anything, this study underscores the importance of preserving the ecological communities in the forest and not just the trees", Mooney said.
Aug 1, 07: Orangutan communication resembles a game of charades, a study suggests. Researchers from St Andrews U have shown that the animals intentionally modify or repeat their signals to get their messages across. The scientists said they believed all great apes could have this capability, suggesting that the skill may have evolved millions of years ago.
. . The study involved six orangutans living in two zoos. Six captive orangutans were presented with a keeper who had treats, such as bananas, and blander food, such as leeks or celery. The animals gestured to attract the keeper's attention so the tasty treat would be passed to them. However, once the orangutans had done this, the keepers did one of three things: they either handed them the treat, handed them the bland food or handed them half the treat. The scientists then recorded their reactions.
. . When the keeper pretended to fail to understand the original gesture and gave the wrong food, the orangutans stopped using the gestures they had used before and started using some different gestures."
. . "And when the keeper half understood and gave the orangutan part of the treat, the orangutans started to repeat the same gestures that they had used, but they would repeat them even more enthusiastically." Professor Byrne likened it to a game of charades.
July 31, 07: Like a secret ingredient to a signature recipe, "survival of the fittest" is a crucial part of the theory of evolution. The fittest individuals survive to mate and pass on their genetic lineage, and the weaker creatures fail to pass on their wimpy genes. But if that's how it works, where do all the runts in nature come from?
. . A new study of red deer populations, detailed in a recent issue of the journal Nature, suggests that a genetic tug-of-war related to sex may be responsible. When red deer search for mates , each sex instinctively looks for different qualities. Males seek out females that will produce the biggest, toughest sons, and females seek males that carry a genetic blueprint for the best offspring-creating daughters.
. . It turns out, however, that the genes that make a good male aren't the same genes that make a good female. Such an evolutionary paradox creates weak members of each sex every generation alongside stronger members, and the "bad" genes don't disappear because they're inextricably tossed back and forth between the sexes, like a hot potato.
July 31, 07: Hungarian scientists said they have discovered a group of fossilized swamp cypress trees preserved from 8 million years ago which could provide clues about the climate of pre-historic times.
July 29, 07: Anglers all have tales about the one that got away, the fish of legendary size that stripped the line from the reel. A new study suggests why that there might indeed be giants and offers an explanation for how they grow so huge.
. . Turns out fishermen themselves can be responsible for the monsters. If a lake or pond is overfished, and a lot of the big ones are caught, the situation is ripe for oversized freaks to develop, according to a new computer model.
. . The research suggests that harvesting only large fish knocks out the food competition for the remaining adults, allowing the adults to gorge on smaller fish and inflate to gigantic proportions. The effect is strongest for fish prone to cannibalizing their own. A Eurasian perch growing in such a situation, for example, can become more than four times as big as an adult fish the same age in a body of water not heavily fished. "The destabilization of a cannibalistic population can induce the growth of 'cannibalistic giants'", scientists write.
July 26, 07: Researchers in northern Greece have uncovered two massive tusks of a prehistoric mastodon that roamed Europe more than 2 million years ago —-tusks that could be the largest of their kind ever found. One of the tusks measured 16-feet-4-inches long and the other was more than 15 feet long.
. . The remains of the mastodon was similar to the woolly mammoth but had straighter tusks as well as different teeth and eating habits. They are thought to have disappeared in Europe and Asia some 2 million years ago, but survived in North America until 10,000 years ago.
July 24, 07: Scientists say they have calculated the date at which the African and the Asian elephant went their separate ways. The two elephant species diverged from a common ancestor some 7.6 million years ago.
. . The now extinct mastodon was very similar in appearance to the woolly mammoth --with lots of hair and big tusks. Genetically, however, it was very different and is only a distant relative of the elephants.
. . Its genetic profile had not previously been mapped, but now thanks to the analysis of material extracted from a fossilised tooth found on the banks of an Alaskan river, scientists have the first genetic portrait of the creature.
. . The tree has the African elephants diverging from both the Asian elephant and the mammoth about 7.6 million years ago. Then, at 6.7 million years ago, the Asian elephant and the mammoth also go their separate ways.
July 19, 07: The ascent of the dinosaurs to the throne of the animal kingdom may have been more gradual than previously believed, scientists said.
. . New fossil discoveries dating from about 215 million years ago showed some of the earliest dinosaurs lived for millions of years side by side with related animals long seen as their ancestors and precursors, scientists said. Many scientists had thought these reptiles --very much like dinosaurs, but more primitive-- died out around the time of the appearance of the first true dinosaurs, which were dog-sized beasts not giants, roughly 230 million years ago.
. . "So they're not the dominant predators or creatures on land at all during most of the Triassic. And it's only really until the Jurassic when they really explode in diversity and reach these huge sizes that we're so familiar with."
. . Scientists previously hypothesized that the first dinosaurs quickly out-competed their more primitive cousins, known as "basal dinosauromorphs", condemning them to extinction. But the new findings indicate that any such competition was prolonged.
. . The newly found fossils from New Mexico dating from the Triassic period showed that the first dinosaurs co-existed with these animals --"dinosaur wannabes", as one scientist called them-- for perhaps 15 to 20 million years.
. . The scientists discovered new dinosaur precursors including one 3 to 5 feet long called Dromomeron and another unnamed one about three times larger that walked on four legs and ate plants with a beaked snout.
. . Relatively small bipedal carnivorous dinosaurs also were found, including Chindesaurus, which measured about 2 meters long, as well as remains of an apparent close relative of the well-known Triassic dinosaur carnivore Coelophysis. They were mere pipsqueaks next to some of their nasty neighbors. The scientists found remains of crocodile-like phytosaurs up to 25 feet long, and a relative of the equally long and vicious four-legged predator Postosuchus.
July 18, 07: An analysis of thousands of skulls shows modern humans originated from a single point in Africa and finally lays to rest the idea of multiple origins, British scientists said. Most researchers agree that mankind spread out of Africa starting about 50,000 years ago, quickly establishing Stone Age cultures throughout Europe, Asia and Australia. But a minority have argued, using skull data, that divergent populations evolved independently in different areas.
. . The genetic evidence has always strongly supported the single origin theory, and now results from a study of more than 6,000 skulls held around the world in academic collections supports this case.
. . Manica and colleagues wrote that variations in skull size and shape decreased the further a skull was away from Africa, just like variations in DNA. The decrease reflects the fact that, while the original African population was stable and varied, only a small number of people embarked on each stage of the multi-step migration out of Africa. This effectively created a series of "bottlenecks", which reduced diversity. The highest level of variation in skull types was seen in southeastern Africa, the generally accepted cradle of mankind.
. . The Cambridge work also suggests in-breeding with other early humans, such as Neandertals, either did not happen or was insignificant.
July 17, 07: New jaw fossils might suggest a direct line of descent between two species of early humans, including the one to which "Lucy" belongs. Lucy and her kind, Australopithecus afarensis, stood upright and walked on two feet, though they might also have been agile tree-climbers.
. . Anthropologists have suspected an ancestor-descendant relationship between the Lucy species and a predecessor --Australopithecus anamensis-- based on their similarities, but lacked fossils from an intervening period.
. . Now, Australopithecus fossils found in Ethiopia, fill the date gap between A. anamensis (4.2 to 3.9 million years ago)—and the Lucy species (3.0 to 3.6 million years ago). The species identifications for all the bones remain uncertain, though it appears that some are A. afarensis. At least 40 hominid specimens have been recovered from the site so far, including the complete jaws and a partial skeleton.
July 15, 07: Chimpanzees scampering on a treadmill have provided support for the notion that ancient human ancestors began walking on two legs because it used less energy than quadrupedal knuckle-walking, scientists said. They said people walking on a treadmill used just a quarter of the energy relative to their size compared to chimpanzees knuckle-walking on four legs.
. . Chimpanzees on occasion walk on two legs in the wild, but are not very good at it. Overall, the chimpanzees used about the same amount of energy walking on two legs compared to four legs, but the researchers saw differences among the individual animals in how much energy they used based on their gaits and anatomy. One, for example, used a longer stride and was more efficient walking on two legs than four.
July 15, 07: A species of egg-laying mammal, named after TV naturalist Sir David Attenborough, is not extinct as was previously thought, say scientists.
. . On a recent visit to Papau's Cyclops Mountains, researchers uncovered burrows and tracks made by the Attenborough's long-beaked echidna. The species is only known to biologists through a specimen from 1961, which is housed in a museum in the Netherlands. The team will return to Papua next year to find and photograph the creature.
. . "Attenborough's echidna is one of five monotremes (egg-laying mammals) that first inhabited the Earth around the time of the dinosaurs. "This group includes the duck-billed platypus, which helps demonstrate how different these are from all other mammals."
July 15, 07: A spine specialist trying to figure out why people so often have bad backs says he has come up with a new theory about when and how early humans evolved the ability to walk upright.
. . The uncannily human-looking backbone of a 21 million-year-old precursor of humans and apes gives the first clue, said Dr. Aaron Filler. A major change in the vertebrae that allowed this pre-human to stand upright and carry things also made it easier to crush and strain the spongy discs between each vertebra, Filler proposes. That, in turn, explains why back pain is a leading cause of disability.
. . Filler said one main clue was a bone feature called the transverse process, which sticks out from the side of the hollow, round vertebrae. This is where muscles attach to the spine. "The vertebra is transformed in a way that literally reverses the mechanics of the spine", Filler said. "The bone lever of the vertebrae gets switched from bending the spine forward to bending the spine back."
. . Most vertebrates are oriented forward, to walk on all fours. The transverse process is at the front of each vertebra, facing the animal's belly. This is true of monkeys, too. But in humans and in the 21 million-year-old fossil of a creature called Morotopithecus bishopi, a tree-dwelling, ape-like creature that lived in what is now Uganda, the transverse process has moved backward, behind the opening for the spinal cord. Great apes, such as chimpanzees, share this feature.
. . In 1997, paleontologist Laura MacLatchy of the State U of New York at Stony Brook reported on the remarkable features of Morotopithecus. "That means that upright posture bipedalism goes back 20 million years, not just 5 or 6 million years", said Filler.
. . In his study and in his new book "The Upright Ape --a new origin of the Species", Filler argues that this common ancestor, and ancestors going back many millions of years before, walked upright. Homo sapiens --the human species-- continued upright, while apes evolved back toward all fours, he argues.
. . He also said humans evolved a new structure of muscles that pull the body from side to side while standing. "This is very important for carrying an infant or child", Filler said. "From the point of view of back pain, now we have big muscles doing this heavy work that never did before. They can get torn and strained."
. . The backward orientation also allows the cushiony discs to get crushed, Filler said. "In most animals the vertebrae get spread apart when they carry infants on their backs when on all fours."
. . What further differentiates humans from apes is the positioning of the place where the spine attaches to the hips, said Filler, who dissected the backbones of dead gibbons, chimpanzees and macaque monkeys and compared them to bones from living and extinct species of other animals and fossils from various pre-humans.
July 12, 07: Scientists say they have seen one of the fastest evolutionary changes ever observed in a species of butterfly. The tropical Blue Moon butterfly has developed a way of fighting back against parasitic bacteria.
. . Six years ago, males accounted for just 1% of the Blue Moon population on two islands in the South Pacific. But by last year, the butterflies had developed a gene to keep the bacteria in check and male numbers were up to about 40% of the population.
. . Scientists believe the comeback is due to "suppressor" genes that control the Wolbachia bacteria that is passed down from the mother and kills the male embryos before they hatch.
. . "To my knowledge, this is the fastest evolutionary change that has ever been observed", said Sylvain Charlat, of University College London. Gregory Hurst, a University College researcher who worked with Mr Charlat said: "We usually think of natural selection as acting slowly, over hundreds of thousands of years. "But the example in this study happened in the blink of the eye, in terms of evolutionary time, and is a remarkable thing to get to observe."
. . The researchers are not sure whether the gene that suppressed the parasite emerged from a mutation in the local population or whether it was introduced by migratory Southeast Asian butterflies in which the mutation existed. "We're witnessing an evolutionary arms race between the parasite and the host. This strengthens the view that parasites can be major drivers in evolution", Mr Charlat said.
July 12, 07: The discovery of a baby mammoth preserved in the Russian permafrost gives researchers their best chance yet to build a genetic map of a species extinct since the Ice Age, a Russian scientist said.
. . The mammoth, a female who died at the age of six months. She had been lying in the frozen ground for up to 40,000 years. Weighing 50 kg, and measuring 85 cm high and 130 cm from trunk to tail, Lyuba is roughly the same size as a large dog.
. . Tikhonov said the fact the mammoth was so remarkably well-preserved --its shaggy coat was gone but otherwise it looked as though it had only recently died-- meant it was a potential treasure trove for scientists.
. . Tikhonov dismissed suggestions the mammoth could be cloned and used to breed a live mammoth. Cloning can only be done if whole cells are intact, but the freezing conditions will have caused the cells to burst.
July 10, 07: Ethiopian scientists said they have discovered hominid fossil fragments dating from between 3.5 million and 3.8 million years ago in what could fill a crucial gap in the understanding of human evolution. "It samples a time period that is poorly known in human evolutionary study."
. . Ethiopian archaeologist Yohannes Haile Selassie said the find included several complete jaws and one partial skeleton and were unearthed in the Afar desert at Woranso-Mille, near where the famous fossil skeleton known as Lucy was found in 1974.
July 4, 07: Researchers say a museum in central Japan has right whale fossils that are at least 5 million years old, making them the oldest fossilized remains of the animal in the world, officials said.
July 4, 07: Orangutans, using water and their wits, have emulated a crow in Aesop's fable which illustrated the saying "Necessity is the mother of invention", German researchers reported. A team at the Max Planck Institute for Evolutionary Anthropology in Leipzig threw down a challenge to five female orangutans, aged seven, 11, 16, 17 and 32.
. . The apes were presented with a tasty peanut that floated in a plastic tube. The container was a quarter-filled with water, which meant that the nut was frustratingly out of reach to the animals.
. . The orangutans realized, though, that by taking mouthfuls of water from a cup placed nearby and spitting the water into the tube, they could make the nut float to the top and recover it easily. At the start, it took the apes nine minutes on average to figure out the trick. But by the end of the 10-trial experiment they had whittled this down to a zippy 30 seconds.
. . The Leipzig team believe this illustrates orangutan inventiveness, showing the primates can use a "liquid tool" to get a reward. Breaking the tube was impossible and there was no stick available as an alternative retrieval method.
July 4, 07: A zebrula --a cross between a horse and a zebra-- has drawn curious onlookers to a zoo in Germany. Its coat is sharply divided between horse and zebra. Eclyse has a zebra head, while the first half of the rest of its body is white and the second half is zebra-colored.
July 4, 07: Villagers in central China dug up a ton of dinosaur bones and boiled them in soup or ground them into powder for traditional medicine, believing they were from flying dragons and had healing powers. Until last year, the fossils were being sold in Henan province as "dragon bones" at about 4 yuan (50 cents) per kg.
. . When the villagers found out the bones were from dinosaurs they donated 200 kg to him and his colleagues for research. The practice had been going on for at least two decades.
July 2, 07: A hybrid scrub oak that looks like a tall, overgrown shrub in a Salt Lake City historical park is a rare and ancient tree from a time when Utah and the Great Basin were warmer and wetter. The branches of the 15-foot-high tree cover nearly an acre.
. . "This tree is significant because it provides evidence of climate change", said Chuck Wullstein, a retired U of Utah biology professor. "There had to be a warm climate for it to be here."
. . Only about a dozen of the trees exist between Salt Lake City and St. George. They are between 5,000 and 7,000 years old. The oak is an indicator that the Earth's climate and ecosystems have changed drastically several times.
. . The hybrid oak has its origins in the warmth-loving canyon live oak, or Quercus turbinella, and the cold-resistant Gambel oak.
July 2, 07: It cruised the skies above the Argentine pampas about six million years ago, a soaring behemoth of a bird, the size of a modern light aircraft, weighing in at 150 pounds or more. But with little in the way of muscle to flap its wings and propel itself through the air, just how did the largest bird to ever take wing stay aloft?
. . US researchers suggest that the now extinct Argentavis magnificens was essentially an expert glider, hitching a lift on thermals and updrafts.
. . Chatterjee and a team of researchers analysed the aerodynamics of the ancient bird of prey by plugging information about its flight parameters into flight simulation software. The analysis showed that the prehistoric aviator, like most large soaring landbirds, was too large to sustain powered flight, but could soar efficiently, reaching speeds of up to 67 mph in the right conditions.
. . Like modern-day condors, the Argentavis would have relied on updrafts in the foothills of the Andes, or columns or pockets of rising air known as thermals over the grassy pampas where it hunted its prey, for lifting power.
. . Although it had a 21-foot wingspan, its 100 foot turning radius was short enough that it could keep circling within a thermal as it rose high to search the plains for its prey.
. . "The hardest part would be taking off from the ground", said Chatterjee. "It would have been impossible to take off from a standing start. "It probably used some of the techniques used by hang-glider pilots such as running on sloping ground to get thrust or energy, or running with a headwind behind it."
July 2, 07: Some of the nastiest bacteria that thrive in the human gut and make us sick may have evolved from hardy ancestors living deep under the sea, a group of Japanese scientists found.
. . The scientists said they had analysed the genetic sequences of two well-known disease-causing gut bugs and compared them to two closely related but harmless bacteria found deep on the ocean bed. They found that they shared many similar genes which enabled them to grow in extreme environments. They also had few DNA repair genes, allowing frequent mutations to occur, and adapted quickly to changing conditions and to the immune response of a symbiotic host.
. . Such characteristics allowed the gut bacteria to "persist in infections", the scientists wrote. "The researchers suggest that human pathogens (gut bugs) evolved from a deep-sea ancestor, and acquired further virulence factors while living in symbiosis with invertebrates", they added.
. . The two gut bugs the scientists selected were the helicobacter, which causes ulcers, and the campylobacter, which causes food-borne diarrhea. The two proteobacteria, sulfurovum and nitratiruptor, are found in very deep seas, areas on the sea floor so hostile that only the hardiest micro-organisms can survive.
July 2, 07: A bizarre hairless rodent living underground in Africa may offer clues about the links between stress and human infertility, scientists said. Stressed-out mole-rats become infertile after constant bullying by the colony's "queen", the only female to reproduce. But this infertility is reversible and when the queen dies, a previously non-breeding female quickly takes her place.
. . Chris Faulkes, a biologist at the U of London, believes the animals' behavior patterns translate into suppression of certain fertility hormones and understanding the process could help explain stress-related infertility in humans. Stress has long been known to be an important factor in infertility in both women and men --but working out why is a challenge.
. . Other creatures exhibiting socially-induced reproductive suppression include primates like marmosets and tamarins, mongooses, and members of the dog family, such as wolves and jackals.
. . In the case of the mole-rats, it appears that ovulatory cycles in females are suppressed by reduction of luteinising and follicle stimulating hormones, while testosterone and sperm count levels fall in non-breeding males.
July 2, 07: Despite their fearsome reputation, piranhas are wimps that gather in large shoals to protect themselves from predators, scientists said. Rather than aggressive killers, research shows piranhas are omnivorous scavengers, eating mainly fish, plants and insects. "Previously it was thought piranhas shoaled as it enabled them to form a cooperative hunting group. However, we have found that it is primarily a defensive behavior", she said. Piranhas face constant attack from predators including river dolphins, caiman --a relative of the crocodile-- and bigger fish, such as the giant piracucu.
Jun 29, 07: Spanish researchers said they had unearthed a human tooth more than one million years old, which they estimated to be the oldest human fossil remain ever discovered in western Europe. The fossil appeared to be "well worn" and from an individual aged between 20-25, & could be as much as 1.2 million years old.
Jun 29, 07: DNA passed down through generations of mothers could help answer big questions about the human journey across continents, thanks to a massive new database created by the The Genographic Project. Researchers collected mitochondrial DNA, or mtDNA, from nearly 80,000 people.
. . The project has already yielded some provocative evidence about modern humans' interactions with Neandertals. The DNA data shows no evidence of mutations known to be common in Neandertals, which suggests that modern humans --at least those of European descent-- may not have mated with the long-extinct humans.
. . "We don't see any Neandertal lineages in the European gene pool", said Spencer Wells, a population geneticist and director of the Genographic Project. "It would be my guess that there was no interbreeding. I can’t imagine that humans and Neanderthals didn't give it a try --maybe they formed infertile offspring. But it's speculative."
. . The database is the tip of the iceberg for a burgeoning field of science called genetic anthropology, which involves combining DNA data with physical evidence and histories of past civilizations. The database contains more samples than in any previous collection of its kind. As scientists study it further, they expect a detailed history of human migration in Europe will emerge.
Jun 28, 07: Genetic study has confirmed what archeologists have suspected for decades --the "Cradle of Civilization" is also the birthplace of the house cat. All domestic cats, from the scrawny strays prowling the markets of Asia to the purebred reclining on the bed of a doting owner, descend from a tabby-like sub-species living in North Africa, the researchers reported.
. . The near Eastern wildcat is the likely ancestor of all the cats whose genes were sampled by the team. There was no separate domestication in Europe or South Africa or China."
. . People were keeping cats as pets more than 9,000 years ago. And their lineage is far more ancient than anyone suspected, originating more than 100,000 years ago. Driscoll is quick to stress, however, that the first cats were not being kept as pets by the pre-humans that existed then. "We weren't out of Africa. We hadn't even domesticated ourselves yet, much less anything else", Driscoll said.
Jun 26, 07: Veterinarian Bob George sliced open the dead shark and saw the outline of a fish. No surprise there, since sharks digest their food slowly. Then George realized he wasn't looking at the stomach of the blacktip reef shark, but at her uterus. In it was a perfectly formed, 10-inch-long shark pup that was almost ready to be born.
. . George was dumbfounded. He had been examining the shark, Tidbit, to figure out why she reacted badly to routine sedatives during a physical and died, hours after biting an aquarium curator on the shin. Now there was a bigger mystery: How did Tidbit get pregnant? "We must have had hanky panky" in the shark tank, he thought.
. . But sharks only breed with sharks of the same species, and there were no male blacktip reef sharks at the Virginia Aquarium.
. . A recent study had documented the first confirmed case of asexual reproduction, or parthenogenesis, among sharks.
. . If the pup indeed turns out to be a hybrid, DNA testing should be able to identify the species of the father. The most likely candidate would be a sandbar shark, the most similar shark to a blacktip reef in the aquarium, George said. He hopes the tests confirm crossbreeding, since that would be a first among sharks.
Jun 26, 07: Bone-crushing wolves that specialized in hunting giant prey once roamed the icy expanses of Alaska, an international team of researchers now finds.
. . The scientists unexpectedly discovered what apparently was a novel subspecies of gray wolf (Canis lupus) as they analyzed genes from skeletal remains that had sat in museum collections for up to a few decades after excavation from Alaskan permafrost deposits. The ancient DNA, which dated back 12,500 to 40,000 years, did not match any modern wolves, and closer investigation of the bones uncovered remarkable differences.
. . These extinct predators had strong jaws and massive teeth, ideal for killing and devouring mammoths and other megafauna. "Studies of their tooth wear and fracture rate showed high levels of both, consistent with regular and frequent bone-cracking and -crunching behavior."
. . These ancient carnivores, with broad skulls and short snouts, faced stiff competition from some very formidable rivals, including lions, short-faced bears and saber-toothed cats.
. . The wolves lived during the Pleistocene epoch, back when an up-to-1,000-mile-long land bridge joined Alaska with Siberia. At the end of the last Ice Age, the ice caps melted and drowned that isthmus under what is now the Bering Strait. As their megafauna prey declined in numbers because of a combination of climate change and over-hunting by humans, the wolves died off.
. . "With global warming coming fast, we might lose a number of specialized forms of species for the same reason." For instance, the tapir -—a somewhat pig-like beast related to horses and rhinoceroses-— is now thought of as mostly a tropical animal, but fossils of tapirs are found as far north as St. Louis and central Pennsylvania during glacial periods 16,000 to 20,000 years ago. "There is a modern tapir that lives in the Andes that can tolerate freezing temperatures, and this extinct species of tapir was probably very similar to the Andean one."
Jun 26, 07: Researchers studying Neandertal DNA say it should be possible to construct a complete genome of the ancient hominid despite the degradation of the DNA over time.
There is also hope for reconstructing the genome of the mammoth and cave bear, according to a research team led by Svante Paabo of the Max Planck Institute for Evolutionary Anthropology.
. . Some researchers believe that Neandertals were simply replaced by early modern humans, while others argue the two groups may have interbred. Sequencing the genome of Neandertals, who lived in Europe until about 30,000 years ago, could shed some light on that question.
. . In studies of Neandertals, cave bear and mammoth, a majority of the DNA recovered was that of microorganisms that colonized the tissues after death, the researchers said. But they were able to identify some DNA from the original animal, and Paabo and his colleagues were able to determine how it broke down over time. They also developed procedures to prevent contamination by the DNA of humans working with the material.
Jun 26, 07: Giant penguins as tall as 5 feet roamed what is now Peru more than 40 million years ago, much earlier than scientists thought the flightless birds had spread to warmer climes. Known mostly for their presence in Antarctica, penguins today live in many islands in the Southern Hemisphere, some even near the equator. But scientists thought they hadn't reached warm areas until about 10 million years ago.
. . Now, researchers report that they have found remains of two types of penguin in Peru that date to 40 million years ago. The big bird is larger than any penguin known today and the third largest known to have ever lived.
. . It is particularly unusual for such a large penguin to have been living in a warm climate, she noted. "In most cases, the larger individuals of a species or among related species are correlated with colder climes and higher latitudes."
. . The earliest known fossil of these aquatic flightless birds, found in New Zealand, dates to about 61 million years ago, not long after the extinction of the dinosaurs and many other life forms 65 million years ago.
. . The largest penguin around today is the Emperor Penguin, which stands almost 4 feet tall. Penguins still live on Peru's coast.
Jun 22, 07: The Gakkel Ridge, encased under the frozen Arctic Ocean, is steep and rocky, and scientists suspect its remote location hosts an array of undiscovered life. Researchers hope newly developed robots will give them their first look.
Jun 21, 07: A battle won by human ancestors against a virus that infected chimpanzees and other primates millions of years ago may have left people today more vulnerable to the AIDS virus, scientists said. That ancient battle helped humans evolve and rely on a gene that may not protect so well against a modern retrovirus, the human immunodeficiency virus or HIV.
. . They focused on an ancient virus, known as Pan troglodytes endogenous retrovirus, or PtERV1, to find clues as to why HIV has exacted such a high toll on humanity. "Events that happened millions of years ago have shaped human evolution, in particular susceptibility to modern human infectious diseases."
. . There is genetic evidence that the PtERV1 virus infected chimpanzees, gorillas and old-world monkeys about 4 million years ago, but no evidence it infected humans. The virus is believed to have gone extinct perhaps 2 million years ago.
. . Emerman's team was able to resurrect a small portion of the PtERV1 by using DNA remnants of the virus lodged in the genome of chimpanzees. Working with cells in a lab, they found that an old virus-fighting gene present in people, known as TRIM5a, succeeded in neutralizing PtERV1. The gene makes a protein that binds to and destroys the virus before it can replicate within the body.
. . "However, while TRIM5a may have served humans well millions of years ago, the antiviral protein does not seem to be good at defending against any of the retroviruses that currently infect humans, such as HIV-1."
. . Other researchers found remnants of the PtERV1 retrovirus in the genomes of chimpanzees, gorillas and some other primates in Africa, but not humans or another great ape, the orangutan. When the chimpanzee genome was mapped, a major difference compared to the human genome was the presence of about 130 copies of PtERV1 in chimpanzees and zero in humans.
Jun 20, 07: Biologists Peter Lawrence and Gines Morata won Spain's prestigious science award today for their work showing that fruit flies and humans have much genetic material in common. Their research showed that this species of fly shares 60% of its genetic makeup with other kinds of animals, including humans.
Jun 20, 07: The discovery of a primitive, shrew-like mammal fossil in Mongolia has revived the view that its modern mammal cousins arrived just as the dinosaurs made their dramatic exit about 65 million years ago, U.S. researchers said.
. . Recent studies have placed the arrival of modern mammals at anywhere from 140 million to 80 million years ago, long before an planetisimal crashed into Earth and wiped out the dinosaurs.
. . Recent molecular studies have held that modern mammals may have lived long *before the dinosaurs died out at the end of the Cretaceous period, which began 145 million years ago and ended with a bang 65 million years ago.
. . Placental mammals --like dogs, cats, mice, whales, elephants, horses and humans-- give birth to live young after a long gestational period. Of the 5,416 species of living mammals, 5,080 are placentals. The rest are marsupials like kangaroos, which nourish their offspring in a pouch, and the very rare monotremes, such as the egg-laying duck-billed platypus.
. . They found that *none of these Cretaceous forms of early mammals are related to any living placental mammals. Wible said his work reinforced the idea that the death of the dinosaurs created an opportunity for explosive growth of modern mammals. "You've got all of these ecological niches that were occupied by the dinosaurs. They go extinct, and you've got wide open spaces. It's like the Oklahoma land rush", he said.
. . The rodent-like creature --one of those evolutionary dead-ends-- lived 75 million years ago, about the time of the Velociraptor, Oviraptor and Protoceratops.
. . "It looks like road kill. It is very well preserved", Wible said. He and colleagues classified the toothsome creature as a new eutherian mammal, a broader group that includes placentals and their extinct relatives. "He would have been a voracious little predator", he said, but it was not a modern placental mammal. "The beauty of this fossil it that it forced us to do the analysis."
Jun 16, 07: [A good lesson here...] It hardly seems fair, but water creatures nimble enough to avoid being gobbled up by predators might harm their species more than help, new research suggests.
. . Fish, amphibians and even tiny zooplankton do many things to escape hungry enemies, from finding new homes to changing their physical characteristics. Such tactics may save individual lives —-but in the long run might leave the population worse off, Michigan State U scientists say. "When you introduce a predator into a system ... the potential prey don't sit around and say, `Eat me'", fisheries biologist Scott Peacor said. "They have adapted to get out of the way. But that comes at a cost."
. . Though the study focused on two particular species in the Great Lakes, it has implications for other predator-prey relationships, Peacor said. They studied what happened when the spiny water flea, an invasive predator native to Europe and Asia, encroached on locations in lakes Erie and Michigan inhabited by a zooplankton species called daphnia.
. . As the water flea's numbers increased, many daphnia withdrew to deeper, darker waters —-apparently having learned to smell their pursuers. The tactic enabled many to survive. But because the water was colder, their community's birth rate plummeted. Some also grew longer spines, making them harder to eat. But it also slowed them down, hampering their own ability to catch food.
. . The study found that such "nonlethal" effects from evading predators could do 10 times more damage to the daphnia population than for some to get eaten. It also showed that invasive species can cause harmful behavioral changes in their prey even when they've been exposed to each other for relatively short periods. "All animals evolve ways to sense predation risk and avoid it, from the (single-cell) paramecium to elephants", he said.
. . The daphnia provides crucial nourishment for juvenile fish such as alewives and smelt that, in turn, are eaten by larger sport fish.
. . When wolves return to an area where they've long been absent, elk spend less time in open spaces —-where they're easier targets-— and more in places with heavier tree growth. But that leaves the elk less time to forage. And it boosts their exposure to another predator: cougars.
Jun 14, 07: Our eyes are moving constantly, and it now appears this motion helps to refine and sharpen the images we see, U.S. researchers said. "It's impossible to keep your eyes perfectly still", said Michele Rucci, director of the Active Perception Laboratory in Boston U.
. . Rucci said researchers have long believed these rapid movements help refresh images we see, but his work shows they do something more. "It tells us these very small eye movements, which are always there and which we almost always ignore, are rather important. They actually provide useful information".
Jun 13, 07: Cockroaches have a memory and can be taught to salivate in response to neutral stimuli in the way that Pavlov's dogs would do when the famed Russian doctor rang his bell, Japanese researchers found. Such "conditioning" can only take place when there is memory and learning, and this salivating response had only previously been proven in humans and dogs.
. . In the experiment, the scientists exposed a group of cockroaches to an odor whenever they fed them a sugar solution. They found that when they later exposed the cockroaches to the odor alone, they still drooled.
. . Another group of cockroaches was fed the sugar solution without the odor, and exposure to the smell afterwards caused no change in the amount of saliva produced.
Jun 13, 07: China has uncovered the skeletal remains of a gigantic, surprisingly bird-like dinosaur, which has been classed as a new species. Eight meters long and standing at twice the height of a man at the shoulder, the fossil of the feathered but flightless Gigantoraptor erlianensis was found in the Erlian basin in Inner Mongolia.
. . They weighed about 1.4 tons and lived some 85 million years ago. According to lines of arrested growth detected on its bones, it died as a young adult in its 11th year of life.
. . What was particularly surprising was its sheer size and weight because most theories point to carnivorous dinosaurs getting smaller as they got more bird-like. "It had no teeth and had a beak. Its forelimbs were very long and we believe it had feathers."
. . Through analyzing its skeleton, the researchers believe the Gigantoraptor shared the same ancestor and belonged to the same family as the Oviraptor. With a beak and feathers, the Oviraptor is also bird-like and flightless, but weighed a mere 1 to 2 kg.
. . Fraser thinks the long-necked specimens may rewrite the books about flying dinosaur evolution. "This is some of the best early evidence of strong aerial mobility", he said. "It's certainly something that will make us look more closely at the origins of flying dinosaurs." Other similar feathered dinosaurs rarely weighed over 40 kg, which means the Gigantoraptor was about 35 times heavier.
. . If the Gigantoraptor had lived to a full-sized adult, it would have been a lot larger, but Xu could not estimate what that would have been. However, the researchers believe it had an accelerated growth rate that was faster than the large North American tyrannosaurs.
. . Its feathers were likely for show and for keeping its eggs warm, Xu added. "We think it's the largest feathered animal ever to have been discovered", he said. It had both herbivorous features --a small head and long neck-- but also carnivorous ones --sharp claws for tearing meat-- and could likely run fast on its long, powerful legs, the professor said.
. . It was as tall as the formidable tyrannosaur. "Almost every group that has evolved has tended to evolve giant forms", Currie said. Animals tend to become bigger with evolution because larger creatures have an easier time getting food, impressing potential mates and avoiding predators.
. . But size has disadvantages, too. Bigger animals need more food and territory. They have fewer offspring and reproduce less frequently than smaller animals do. That means they are particularly vulnerable when environmental conditions change, as they abruptly did about 65 million years ago. Just a few million years after Gigantoraptor evolved, it and every other dinosaur species on Earth became extinct.
. . It has not been determined whether the Gigantoraptor was a herbivore, which have small heads and long necks, or a carnivore, which have sharp claws. The dinosaur has both.
Jun 13, 07: An in-depth examination of the human DNA map has turned basic biology concepts upside-down and may even rewrite the book on evolution and some causes of disease, researchers said. Thirty-five teams of researchers from 80 different organizations in 11 countries teamed up to share notes on just 1% of the human genome.
. . They found there was far more to genetics than the genes themselves and determined there was no such thing as "junk DNA" but that some of the most useless-looking stretches of DNA may carry important information. When the human genome was published in 2003, some scientists voiced surprise that human beings had only about 30,000 genes. Rice, for instance, has 50,000.
. . The new study confirms what many genetics experts had suspected --the genes are important, but so is the other DNA, the biological code for every living thing. What they discovered is that even DNA outside the genes transcribes information. Transcription is the process that turns DNA into something useful --such as a protein.
. . The researchers did find some DNA that appears to do nothing, and it can mutate without causing any damage. Collins likened these stretches of DNA to boxes in the attic. "It is not the sort of clutter that you get rid of without consequences because you might need it. Evolution may need it."
Jun 13, 07: Paleontologists have discovered a new small gliding reptile in 220 million-year-old sediments of a quarry on the Virginia-North Carolina border. The new creature is named Mecistotrachelos apeoros, meaning "soaring, long-necked" and is about the size of a blue jay from head to tail.
. . "One of the really neat things about the new glider is the feet,” said Nick Fraser of the Virginia Museum of Natural History, who discovered the two fossils. “They are preserved in a hooked posture which is unusual and strongly suggests a grasping habit. I'm convinced it was using its hind limbs for grasping branches." Fraser noted that the Triassic Period reptile probably fed on insects, scuttling up tree trunks and foraging on the way, before gliding onto neighboring trees.
. . Because the fossils formed in brittle shale sediments, Fraser and his team relied entirely on computed tomography scans, or CT scans, to study the specimens. The technology is typically used to create 3-D medical images of patients' bodies but in this case helped peer inside the shale to reveal the fossils.
Jun 12, 07: Europe's prehistoric hunter-gatherers may have practiced human sacrifice, a new study claims. Investigating a collection of graves from the Upper Paleolithic (about 26,000 to 8,000 BC), archaeologists found several that contained pairs or even groups of people with rich burial offerings and decoration. Many of the remains were young or had deformities, such as dwarfism.
. . The diversity of the individuals buried together and the special treatment they received could be a sign of ritual killing, said Vincenzo Formicola of the U of Pisa, Italy. "These findings point to the possibility that human sacrifices were part of the ritual activity of these populations."
. . The mix and match of ages and sexes buried in each grave indicates that they were put together for a reason and not just due to a common disease, said Formicola.
Jun 9, 07: More than a hundred species of tiny land-breeding frogs in the Caribbean evolved from a single South American species that probably hitched a ride on a raft of vegetation and washed up on an island beach, according to scientists.
Jun 6, 07: Elephants use their feet to "hear" calls from other herds but react most if the calls come from elephants they know. Elephants are already known for their ability to emit low-frequency sounds to communicate with herds up to several km away.
. . Researchers led by Caitlin O'Connell-Rodwell of Stanford U Medical Center in California also suspected that these rumblings generate seismic waves that travel through the ground, enabling elephants to pick up the signals through their surprisingly sensitive feet.
. . Her team recorded alarm calls in Namibia and Kenya made by elephants when lions were lurking. They then played just the seismic portion of the sound through the ground to herds at watering holes in Namibia. The elephants "reacted dramatically, first freezing and then clumping in tight groups, with babies in the middle."
. . But the farther the elephants lived from the herd which made the call, the less they reacted. What was especially curious was that the Namibian elephants responded least to alarm calls from herds in Kenya, apparently because these animals were unfamiliar to them. [diff "dialect"]
Jun 5, 07: A mushroom found embedded in a 100-million-year-old piece of amber is about 20 million years older than other known mushroom fossils, an Oregon scientist says.
. . The ancient mushroom is especially interesting because it contains two parasites, one feeding on the mushroom and the other feeding on its fellow parasite. "I was amazed enough with the mushroom", said George Poinar, a retired entomology professor in Corvallis. "But then seeing the parasites was astonishing. No one has ever seen this three-tier association before."
. . Amber is fossilized tree resin, a sticky substance that oozes from certain pine and legume trees. The resin has chemical properties that act as a natural embalming agent for the ancient creatures that become trapped in it.
. . Poinar received attention last year for his discovery of what is considered the oldest bee ever found —-a 100-million-year-old specimen from the same area in northern Burma where the amber is mined. Four kinds of flowers also were embedded in the amber.
Jun 4, 07: A Tyrannosaurus rex would have had great difficulty getting its jaws on fast, agile prey, a study confirms. A US team has used detailed computer models to work out the weight of a typical "king of the dinosaurs", and determine how it ran and turned. The results indicate a 6-8 ton T. rex was unlikely to have topped 40km/h (25mph) and would have taken a couple of seconds to swivel 45 degrees.
. . They built on previous work detailing the biomechanics of the famous dinosaur, but add in new refinements. "We've now got a pretty good estimate of its weight --over which there's been some controversy", lead author Dr John Hutchinson explained. "We've shown there's no way it could weigh 3-4 tons as some people have suggested. It had to have weighed 6-8 tons."
. . The team's computer modelling system estimated the centre of mass position and the inertia (resistance to turning), which have ramifications for how T. rex would have stood and moved and what it would have looked like.
. . As well as predicting the dinosaur's likely body mass and top speed (25-40km/h or 15-25mph), the computer calculations gave the team an idea of the turning ability of a T. rex. This has never been done before.
. . The study indicates the animal would have changed direction incredibly slowly due to its massive inertia, taking one or two seconds to make a quarter-turn. The species certainly could not have pirouetted rapidly on one leg, as popular illustrations have sometimes pictured it, and other large dinosaurs, doing. More agile prey would have given the slip to a marauding T. rex quite easily, it seems. "It wasn't like the Serengeti today where everything is done at top speed."
Jun 2, 07: Like dogs, sharks rely on a keen sense of smell to track down food. But new research shows noses aren’t the only way that sharks detect smells: Their entire bodies, in fact, function as giant noses capable of even picking up the “shape” of a smell.
. . Running down the sides of every shark are nerve-packed strips called lateral lines. Researchers know these sensitive structures can detect the faint vibrations emitted by living things in water, but their ability to pick up scent was previously unknown. Even more surprising, researchers said, is that lateral lines can detect the 3-D “plumes” of scents—structures resembling the turbulence left behind after waving a hand through thick fog or steam. "Odor plumes are complex, dynamic, three-dimensional structures used by many animal species to locate food, mates and home sites." When deprived of the “odor plume” information, the study shows, sharks are unable to find the source of an odor.
Jun 2, 07: A chicken bone found in Chile provides solid evidence to settle a debate over whether Polynesians traveling on rafts visited South America thousands of years ago -- or vice versa, researchers said on Monday.
. . The DNA in the bone carries a rare mutation that links it to chickens in Tonga and Samoa, and radiocarbon dating shows it is around 600 years old --meaning it predates the arrival of Spanish conquerors in South America. "These chickens are related to hens from Polynesia."
. . This suggests that best-selling author and adventurer Thor Heyerdahl was only partly right when he sailed on the raft Kon-Tiki from South America to Polynesia to prove prehistoric contact across the Pacific.
. . Luckily for the researchers, the chicken DNA carries a rare mutation. It is identical to bones from two prehistoric archeological sites in the Pacific: Mele Havea in Tonga, dating to 2,000 years ago, and one from American Samoa, about the same age as the Chilean site.
Jun 1, 07: The way orangutans navigate fragile tree branches in search of fruit has led scientists to propose that human ancestors with similar lifestyles may have begun walking on two legs earlier than previously thought.
. . Three British scientists suggested that bipedal walking arose in arboreal apes 17 to 24 million years ago, rather than between 4 and 8 million years ago, as a leading hypothesis indicates.
. . Observations of wild orangutans navigating tree branches on two legs led these researchers to propose that bipedalism arose much earlier --perhaps shortly after apes split evolutionarily from monkeys roughly 24 million years ago, assuming a specialized niche of tree-dwelling fruit eaters.
May 28, 07: An Indian zoologist said today he has found a new species of limbless lizard in a forested area in the country's east. The newly found 7-inch long lizard looks like a scaly, small snake, Dutta said. "It prefers to live in a cool retreat, soft soil and below stones."
. . While modern snakes and lizards are derived from a common evolutionary ancestor, they belong today to two entirely separate groups of animals, or orders. Snakes, over millenia, gradually lost their limbs and developed their characteristic forms of locomotion. But modern limbless lizards are not snakes, Dutta said.
. . The other limbless lizards belonging to different families have been found in India's Nicobar island, in the northeast, and in Orissa and Andhra Pradesh states, he said. The closest relatives of the new species are found in Sri Lanka and South Africa.
May 25, 07: Researcher Matt Mossbrucker believes four small dinosaur tracks found within sight of the skyscrapers of downtown Denver were made by two stegosaur babies, a find he says would be "incredibly rare". Some other researchers agree the tracks were left by stegosaur toddlers, but still others have their doubts.
. . Mossbrucker, director of the Morrison Natural History Museum, said the half-dollar-size tracks were discovered in the foothills just west of Denver last year, but it took time and digging for him to conclude they were made by stegosaur babies. The tracks were found not far from the site where the first known stegosaur bones were unearthed 130 years ago.
. . Little is known about stegosaurs except that they were plant-eaters and grew to weigh about six tons. Because their feet were relatively small, their tracks are hard to find, and as a result little is known about how quickly they grew, how long they lived and how they survived as well as they did in a time and place where plants were scarce. Baby footprints, combined with the bones and another adult imprint already at the Morrison museum, could help answer some of those questions.
. . Paleontologist Robert Bakker, a curator at the Houston Museum of Natural Science and volunteer curator in Morrison, agrees with Mossbrucker that the newly analyzed prints are those of stegosaurus babies.
May 24, 07: The skeleton of a bear-like creature believed to be about 60 million years old has been found in the North Dakota Badlands, the state paleontologist says.
. . The titanoides fossil was found during a survey of an oil drilling site. Partial skeletons have been found before in North Dakota, but the latest discovery could be complete or close to it, he said. It was about 5 feet long, weighing between 95 and 140 kg.
. . The landscape was much different when the titanoides roamed the area, Hoganson said. "It was subtropical, for example, and it was a forested swampland. So during the time, it was somewhat similar to southern Florida today."
May 24, 07: Dolphins living off the coast of Wales whistle, bark and groan in a different dialect from dolphins off the western coast of Ireland, scientists have discovered.
. . Different physical environments might have contributed to the mammals developing distinctive sets of vocalizations or "dialects", said Simon Berrow from the Shannon Dolphin and Wildlife Foundation.
. . Berrow supervised a master's thesis by student Ronan Hickey at University of Wales, Bangor, who analyzed 1,882 whistles from the dolphins in the Shannon estuary and bottlenose dolphins in Cardigan Bay in Wales. The study found 32 different sound categories, of which eight were only produced by the Shannon animals.
May 24, 07: Ancient footprints have provided compelling evidence that some dinosaurs were able to swim, scientists report. The 15 meter trackway that reveals one animal's underwater odyssey was discovered in the Cameros Basin in Spain, once a vast lake.
. . The S-shaped prints suggest the beast clawed at sediment on the lake floor as it swam in about 3m of water. The marks are about 125 million years old, dating to the Early Cretaceous. They were left by a large, bipedal, carnivorous dinosaur.
. . The underwater trackway, which is well-preserved in sandstone, is made up of 12 consecutive prints each consisting of two to three scratch marks. "The footprints are really peculiar in their shape and morphology --they are not at all like walking footprints." "You get the idea that the animals' body was supported by water as it was scratching the sediment." Ripple marks around the track suggested the dinosaur was swimming against a current, attempting to keep a straight path, the team said.
. . Further investigation of the well-preserved track revealed more about the beast's swimming style. "The dinosaur swam with alternating movements of the two hind limbs: a pelvic paddle swimming motion", said Dr Costeur. "It is a swimming style of amplified walking with movements similar to those used by modern bipeds, including aquatic birds."
May 23, 07: Primitive fish already may have possessed the genetic wiring needed to grow hands and feet well before the appearance of the first animals with limbs roughly 365 million years ago, scientists said. A genetic study has shed light on the mystery of how fish made the move from water to land millions of years ago. Previous research had suggested that fish had made an abrupt genetic jump to acquire land-friendly limbs. But a US team has now shown this event was not an evolutionary novelty and the transition was far more gradual.
. . The study follows the recent discovery of a fossil described as showing the "missing link" between fins and limbs.
. . In 2004, the fossilized remains of the Tiktaalik roseae revealed an animal with fins that were equipped for a life in the water but also for support on land. The crocodile-like creature, which lived about 380 million years ago, was said to "blur the distinctions" between land- and water-dwelling animals.
. . Dr Davis and his colleagues decided to repeat the studies --but this time using paddlefish, which have a fin pattern similar to primitive fish. "We found a very clear second phase in their fins - and this tells us that the second key phase of Hox-expression is in fact a much more ancient pattern of development.
. . Paddlefish are similar to ancient fish. "It seems that some fish have always had this genetic toolkit to modify their fins --it just seems like tetrapods have modified it in this unique and elaborate way." The reason why some of these primitive fish went on to become land-living animals while others remained in the water was most probably influenced by their environment.
May 21, 07: A controversial new idea suggests that a large space rock exploded over North America 13,000 years ago. The blast may have wiped out one of America's first Stone Age cultures as well as the continent's big mammals such as the mammoth and the mastodon. The blast, from a comet or planetisimal, caused a major bout of climatic cooling which may also have affected human cultures emerging in Europe and Asia.
. . The evidence comes from layers of sediment at more than 20 sites across North America. These sediments contain exotic materials: tiny spheres of glass and carbon, ultra-small specks of diamond --called nanodiamond-- and amounts of the rare element iridium that are too high to have come from Earth. All, they argue, point to the explosion 12,900 years ago of an extraterrestrial object up to 5km across.
. . No crater remains, possibly because the Laurentide Ice Sheet, which blanketed thousands of sq km of North America during the last Ice Age, was thick enough to mask the impact. Another possibility is that it exploded in the air.
. . The rocks studied by the researchers have a black layer which, they argue, is the charcoal deposited by wildfires which swept the continent after the explosion. The blast would not only have generated enormous amounts of heat that could have given rise to wildfires, but also brought about a period of climate cooling that lasted 1,000 years --an event known as the Younger Dryas.
. . Professor James Kennett, from the U of California in Santa Barbara, said the explosion could be to blame for the extinction of several large North American mammals. "All the elephants, including the mastodon and the mammoth, all the ground sloths, including the giant ground sloth --which, when standing on its hind legs, would have been as big as a mammoth. All the horses went out, all the North American camels went out. There were large carnivores like the sabre-toothed cat and an enormous bear called the short-faced bear." Professor Kennett said this could have had an enormous impact on human populations.
. . Archaeologists have found evidence from the Topper site in South Carolina, US, that Clovis populations here went through a population collapse. But there is no evidence of a similar decline in other parts of the continent. The Clovis culture does vanish from the archaeological record abruptly, but it is replaced by a myriad of different local hunter-gatherer cultures.
. . The comet would have caused widespread melting of the North American ice sheet. The waters would have poured into the Atlantic, disrupting its currents. This, they say, could have caused the 1,000 year-long Younger Dryas cold spell, which also affected Asia and Europe.
. . A massive explosion near the Tunguska river, Siberia, in 1908, is also thought to have been caused by a space rock exploding in the atmosphere. It felled 80 million trees over an area of 2,000 sq km.
May 16, 07: Carnivorous sponges, 585 new species of crustaceans and hundreds of new worms have been discovered in the dark waters around Antarctica, suggesting these depths may have been the source of much marine life, European researchers reported.
. . The team, who scooped samples from as deep as 20,000 feet, found unexpectedly rich diversity of animal life. Many belong to species found around the world, notably in the Arctic, while others appear to be unique to the deepest Antarctic waters, the researchers reported. The unique species tend to be the kind that do not spread easily, which suggests the deep, cold southern oceans may have been the source of many types of marine life.
. . "We now have a better understanding in the evolution of the marine species and how they can adapt to changes in climate and environments", Brandt, who led the expedition, said.
. . Among the new creatures they documented are a gourd-shaped carnivorous sponge called Chondrocladia; free-swimming worms and 674 species of isopod, a diverse order of crustaceans that includes woodlice, also commonly called pillbugs, sea lice or sea centipedes.
. . Of the isopod crustaceans, 585 species had never been seen before. "What was once thought to be a featureless abyss is in fact a dynamic, variable and biologically rich environment", Katrin Linse, a marine biologist.
May 15, 07: Scientists in Scotland have discovered that female chimpanzees can be just as violent as their male counterparts. The St Andrews U psychologists found examples of female chimps killing the offspring of incoming mothers, previously regarded as a male trait. One attack was so violent that a baby chimp's head was bitten off.
May 14, 07: A monkey-like animal seen as an ancestor of monkeys, apes and humans was not as brainy as expected, according to scientists who analyzed its nicely preserved 29-million-year-old skull. The finding indicated that primate brain enlargement evolved later than once thought, the researchers said.
. . They analyzed a remarkably well-preserved fossilized skull of the little primate Aegyptopithecus zeuxis, which lived in the trees and ate fruit and leaves about 29 million years ago in warm forests in what is now an Egyptian desert. Its sometimes called "Dawn Ape."
. . A technique called microcomputerized tomography scanning --a computerized X-ray method also called micro-CT-- allowed them to determine the dimensions of the animal's brain.
. . Based on earlier finds, scientists had theorized the species had a relatively large brain. Instead, it had a brain that might have been even smaller than that of a modern lemur, a primate with primitive traits. The condition of the earlier skull --"smashed up", as Simons put it-- prevented the analysis that was possible with the newer one.
. . Simons said that when this primate lived, Africa was an island, limiting the competition for survival. Simons said brain enlargement may have evolved in this lineage after Africa became connected to Asia, bringing in more animals including new and dangerous predators. "Brain-volume enlargement is favored under conditions of competition because you need to be smarter", Simons said.
. . The new skull fits easily into a person's palm and is less than half the size of the 1966 skull. The researchers think it was from a female weighing perhaps 2.5 kg, while the earlier one was from a male more than twice as big. They said this size difference between the sexes of this species is similar to that of gorillas.
. . Other aspects of its remains indicate it was branching off from its lemur-like ancestors. Its skull indicates the brain's visual cortex was large, suggesting it had very good vision --an important characteristic of higher primates. Its eye sockets also indicate it was active during the day. Many more primitive primates are nocturnal.
May 10, 07: Bats and birds, the only two vertebrate fliers on Earth, use their wings very differently, according to scientists who observed small, nectar-feeding bats flying through fog in a wind tunnel filled with fog from a fog machine. The scientists tracked the movement of fog particles in the wake left by the flying bats to understand the aerodynamics of each wing beat.
. . Scientists had studied birds flying in similar wind tunnels previously.They both fly by flapping their wings, but use the upstroke of the flap in different ways, with bats flicking their wings upward and backward unlike birds to gain lift.
. . Powered flight has evolved three times among vertebrates in the history of life on Earth. [Four, if you count that bat-flight evolved twice.] The first to achieve the feat were flying reptiles known as pterosaurs. They first appeared roughly 220 million years ago but died along with the dinosaurs 65 million years ago when an planetisimal slammed into Earth. Scientists think birds descended from small, feathered dinosaurs roughly 150 million years ago. They survived the planetisimal impact.
. . Bats, which generally are nocturnal, are the only mammals to have developed powered flight --some, like flying squirrels, glide but do not fly. Bats arose about 50 million years ago.
. . The wing structure of bats and birds differs. Birds have feathers projecting back from lightweight, fused arm and hand bones. Bats have flexible, relatively short wings with membranes stretched between elongated fingers. Spedding said while birds can open their feathers like a Venetian blind, bats have developed a twisting wing path that increases the lift during the upstroke.
. . There are about 1,000 species of bats, accounting for about 20% of mammal species. Most catch insects.
May 10, 07: Scientists have mapped the genetic composition of a marsupial mammal, the South American gray, short-tailed opossum, gaining insight into the role of "junk DNA" in human evolution and into immune systems.
. . Because this opossum develops melanoma skin cancer much as people do and its newborns can regenerate a severed spinal cord, scientists hope studying its genome can boost research into treating human skin cancer and neurological ailments.
May 8, 07: The world's scientists plan to compile everything they know about all of Earth's 1.8 million known species and put it all on one Web site, open to everyone. The effort, called the Encyclopedia of Life, will include species descriptions, pictures, maps, videos, sound, sightings by amateurs, and links to entire genomes and scientific journal papers. The project will take about 10 years to finish, & fill about 300 million pages.
. . For more than a decade, scientists have tried to compile even just a list of all species on Earth, but failed. It's been too complicated, too expensive and too cumbersome. This effort may succeed where the others have faltered because of new search engine technology, the scientists said.
May 6, 07: North America's oldest conifer tree and some ancient scorpion parts are among the fossil treasures found in a newly discovered cave in Illinois. The new discovery also unearthed fossils of plants that may be new to science and revealed evidence of prehistoric forest fires. Scientists date the specimens to nearly 315 million years ago. The most fascinating discoveries in the cave include:
. . * Needles of a conifer tree, 2 million years older than any conifer previously described
. . * Nearly pristine plant spores of lycopods, the main coal-forming plants of the period
. . * Evidence of a general drying trend in the area.
The cave, which geologists estimate runs underground for miles, could provide scientists with years of research material.
May 6, 07: Neandertals disappeared from Earth more than 20,000 years ago, but figuring out why continues to challenge anthropologists. One team of scientists, however, now says they have evidence to back climate change as the main culprit.
. . The Iberian Peninsula, better known as present-day Spain and Portugal, was one of the last Neandertal refuges. Many scientists have thought that out-hunting by Homo sapiens and interbreeding with them brought Neandertals to their demise, but climate change has also been proposed. Francisco Jiménez-Espejo, a paleoclimatologist at the U of Granada in Spain, says a lack of evidence has left climate change weakly supported -—until now.
. . To figure out the temperature, water supply, and windiness of Iberia from 20,000 to 40,000 years ago, the scientists looked at sediments on the ocean floor off Spain and Portugal. Because wind or water erode rocky minerals differently, the pebbles and fragments wash into the sea in different ratios, creating a steady track record of land conditions at the bottom of the ocean.
. . The scientists also focused on barite, a compound gathered by marine animals. The more barite in sediment, the more lively the oceans were at the time. “When we found big drops in marine productivity, we knew there were big changes in climatic condition in Iberia.”
. . The study reveals three rough climatic periods for Neandertals, with the last and harshest period starting about 26,000 years ago. “The last event was very, very cold and dry, and --other than 250,000 years ago-- such a harsh climate was never reached before.”
. . But is climate change the only reason Neandertals died out? “We’re not saying that”, Jiménez-Espejo said. “What we are saying: Neandertals struggled with climate change more than modern humans, and during the period of their extinction, very unfavorable climatic conditions were present.”
. . Other scientists think less game for Neandertals to hunt -—and not having modern humans’ skills to hunt them—probably sealed our humanoid cousin’s demise.
May 5, 07: Paleontologists unearthed a flesh-eating dinosaur some 150 million years old in southern Argentina with all its joints in place, the first time such a beast has been dug up so intact. The seven-meter tall, two-legged dinosaur, dubbed the Condorraptor, was found fossilized with parts of its jaw and head showing in rock.
May 4, 07: In a case that could set a global legal precedent for granting basic rights to apes, animal rights advocates are seeking to get the 26-year-old male chimpanzee legally declared a "person." Hiasl's supporters argue he needs that status to become a legal entity that can receive donations and get a guardian to look out for his interests.
. . The Association Against Animal Factories, a Vienna animal rights group: "We mean the right to life, the right to not be tortured, the right to freedom under certain conditions", Theuer said. "We're not talking about the right to vote here."
. . The campaign began after the animal sanctuary where Hiasl (pronounced HEE-zul) and another chimp, Rosi, have lived for 25 years went bankrupt. Activists want to ensure the apes don't wind up homeless if the shelter closes. Both have already suffered: They were captured as babies in Sierra Leone in 1982 and smuggled in a crate to Austria for use in pharmaceutical experiments. Customs officers intercepted the shipment and turned the chimps over to the shelter.
. . Their food and veterinary bills run about $6,800 a month. Donors have offered to help, but there's a catch: Under Austrian law, only a person can receive personal donations. A date for the appeal hasn't been set, but Hiasl's legal team has lined up expert witnesses, including Jane Goodall, the world's foremost observer of chimpanzee behavior.
. . Spain's parliament is considering a bill that would endorse the Great Ape Project, a Seattle-based international initiative to extend "fundamental moral and legal protections" to apes. "Chimps share 99.4% of their DNA with humans", he said. "OK, they're not homo sapiens. But they're obviously also not things —-the only other option the law provides."
May 3, 07: Mexican scientists said they have identified the world's oldest lobster fossil, a creature that was alive when Africa was only just breaking apart from the Americas some 120 million years ago.
. . The fossil is 4.7 inches long and its shell and legs are immaculately preserved by the mud in the southern state of Chiapas where it was found. It is dated as 120 million years old, some 20 million years older than existing lobster fossils.
. . South America and Africa are believed to have split into two continents around 120 million years ago. Species sometimes evolved differently on the two continents, explaining why American lobsters today are different from their African cousins.
May 3, 07: Fossil bones from the largest dinosaurs ever known to walk Australia were unveiled. The remains of two Titanosaurs, nicknamed Cooper and George, were uncovered by farmers in 2005 and 2006, but were kept secret to allow investigation.
. . Fossilized leg bones showed the pair were 6-7 meters longer than the biggest sauropod dinosaur previously found in Australia. Titanosaurs, with their long necks and tails, were among the heaviest creatures to walk the earth, weighing up to 100 metric tons, and were one of the last sauropods of the Cretaceous Period. The two dinosaurs would have been at least 26 meters long, but may even have rivaled the largest ever found, the 35-meter Argentinosaurus.
. . They roamed Australia 98 million years ago, when the continent was greener and wetter, living on plants until prehistoric climate change saw their extinction. They were named after the Titans of Greek myth and lived in mainly southern parts of the ancient supercontinent Gondwana.
May 1, 07: A gene that helps control muscle development makes all the difference, scientists reported today.
. . Racing whippets that carried one copy of the mutated gene were among the fastest runners, but those that carried two copies became unattractively bulky and were usually destroyed by breeders, the researchers said.
. . The next step may be to look for this gene in human athletes to see if it helps explain what makes some competitors excel, said Dr. Elaine Ostrander of the National Human Genome Research Institute, who led the study.
. . The gene controls a muscle protein called myostatin. "Our work is the first to link athletic performance to a mutation in the myostatin gene and could have implications for competitive sports in dogs, horses and possibly even humans", Ostrander said.
. . Just last month, it was reported that a gene called IGF1 was responsible for making small dogs small. They believe this has implications for differences in human size, as well.
. . While studying whippets, a small, very thin racing breed, they noticed ones that were big and bulky called "bully" whippets. "They were very, very heavily muscled", Ostrander said. "We were really struck by their remarkable physical appearance."
. . But breeders do not like them. "The bottom line is, these dogs are not given a chance. When they are born, breeders in this community will describe their appearance as grotesque", she said. Such whippets are usually put down immediately. The dogs resembled a breed of Belgian blue cattle and certain pigs, and Ostrander's team knew that in livestock this muscling came from a mutation in the myostatin gene.
. . They looked at the parents of the mutant whippets. "They were absolutely gorgeous dogs", she said. Well-muscled and sleek, they lacked the anorexic appearance of most racing whippets, Ostrander said. It turned out the parents each had just one copy of the mutated genes, while their "bully" offspring carried two copies.
. . When they learned one of these parents was called "Fast Eddie", Ostrander's team knew what to look for next. "We wanted to know whether or not this was something that could explain racing speed", she said. So her team visited a dog track and got DNA samples from the dogs.
. . Racing whippets are classified as A, B, C or D, with A racers being the fastest, Ostrander said. They found the mutation in 12 of 41 dogs graded A or B racers, and in just one of the 43 dogs in the slowest racing grades.
. . The gene, called MSTN, affects "fast-twitch" muscle, which is linked to sprinting ability. Tests of greyhounds, close relatives of whippets, did not find the gene, and Ostrander noted that in cattle with the mutation the lungs are abnormally small. Checks of other dog breeds such as Rottweilers, bulldogs and bull terriers found no evidence of the mutation.
May 1, 07: A male chimpanzee may beg for food from another chimpanzee by gesturing with an extended arm and open hand. Under different circumstances, the same chimpanzee may use the same gesture to try to coax a female chimp to have sex. And the same gesture may be used after two males fight as a signal of reconciliation.
. . Scientists seeking clues to the origins of human language analyzed the way two types of apes genetically closely related to people --chimpanzees and bonobos-- use such hand and limb gestures to communicate. They found that the apes use such gestures much more flexibly --in different contexts with apparently different meanings-- than they used facial expressions and vocalizations. The findings, they believe, lend support to the idea that human language started with such gestures rather than speech.
. . Although all primates use their voices and facial expressions to communicate, only people and the great apes --chimpanzees, bonobos, orangutan and gorillas-- use these types of gestures as well. De Waal noted that great apes first appeared about 15 to 20 million years ago, meaning such gestures may have been around that long.
. . The researchers cited differences between the bonobos, the gentler and more sex-crazed; and chimpanzees, the more violent. The bonobos employed various gestures more flexibly, combining them with vocalizations and facial expressions to communicate a message.
. . De Waal said there might have been advantages to developing language from gestures before the spoken word. For example, silent communication might have been better when hunting for big prey. He added that when the apes gesture, they like to use their right hands, which is controlled by the left side of the brain --the same side where the language control center appears in the human brain.
Apr 23, 07: The rise and fall of species on Earth might be driven in part by the undulating motions of the Solar System as it travels through the disk of the Milky Way, scientists say.
. . Two years ago, scientists at the U of California, Berkeley found the marine fossil record shows that biodiversity-the number of different species alive on the planet-increases and decreases on a 62-million-year cycle. At least two of the Earth's great mass extinctions-the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago-correspond with peaks of this cycle, which can't be explained by evolutionary theory.
. . Now, a team of researchers at the U of Kansas (KU) have come up with an out-of-this-world explanation. Their idea hinges upon the fact that, appearances aside, stars are not fixed in space. They move around, sometimes rushing headlong through galaxies, or approaching close enough to one another for brief cosmic trysts.
. . In particular, our Sun moves toward and away from the Milky Way's center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years --suspiciously similar to Earth's biodiversity cycle.
. . The KU researchers independently confirmed the biodiversity cycle and have proposed a novel mechanism by which the Sun's galactic travels is causing it.
. . Scientists know the Milky Way is being gravitationally pulled toward a massive cluster of galaxies, called the Virgo Cluster, located about 50 million light years away. Adrian Melott and his colleague Mikhail Medvedev, both KU researchers, speculate that as the Milky Way hurdles towards the Virgo Cluster, it generates a so-called bow shock in front of it that is similar to the shock wave created by a supersonic jet.
. . "Our Solar System has a shock wave around it, and it produces a good quantity of the cosmic rays that hit the Earth. Why shouldn't the galaxy have a shock wave, too?" Melott said. The galactic bow shock is only present on the north side of the Milky Way's galactic plane, because that is the side facing the Virgo Cluster as it moves through space, and it would cause superheated gas and cosmic rays to stream behind it, the researchers say. Normally, our galaxy's magnetic field shields our solar system from this "galactic wind." But every 64 million years, the solar system's cyclical travels take it above the galactic plane.
. . Cosmic rays are also associated with increased cloud cover, which could cool the planet by blocking out more of the Sun's rays. They also interact with molecules in the atmosphere to create nitrogen oxide, a gas that eats away at our planet's ozone layer, which protects us from the Sun's harmful ultraviolet rays.
. . Richard Muller, one of the UC Berkeley physicists who co-discovered the cycle, said Melott and his colleagues have come up with a plausible galactic explanation for the biodiversity cycle. Muller and Robert Rohde also speculated that our solar system's movement through the galactic plane was behind the cycle, but the pair could not conceive of any reason why conditions on the north and south side of the galactic plane should differ.
. . Richard Bambach, a paleontologist at the Smithsonian Museum of Natural History who was not involved in the study, said he is excited the biodiversity cycle has been independently confirmed, but cautions the galactic hypothesis is still in the early stages of formulation.
. . "It's a first-step hypothesis", Bambach said. "It's an interesting idea, but we're a long way from knowing if that is really why biodiversity changes." For one thing, scientists have yet to discover a bow shock around the Milky Way, though such shock waves have been found around other galaxies.
Apr 23, 07: Scientists exploring a mine have uncovered a natural Sistine chapel, incredibly well preserved images of sprawling tree trunks and fallen leaves that once breathed life into an ancient rainforest.
. . Replete with a diverse mix of extinct plants, the 300-million-year-old fossilized forest is revealing clues about the ecology of Earth’s first rainforests. Over millions of years, as sediments and plant material pile up, layer upon layer, the resulting bands become time indicators.
. . A coal mine offers a unique view of the past. Instead of a time sequence, illuminated in the layer upon layer of sediments, the roof of an underground mine reveals a large area within one of those sediment layers, or time periods. Miners in Illinois are used to seeing a few plant fossils strewn along a mine’s ceiling, but as they burrowed farther into this one, the sheer density and area covered by such fossils struck them as phenomenal.
. . The largest ever found, the fossil forest covers an area of about 40 square miles, or nearly the size of San Francisco. This ancient assemblage of flora is thought to be one of the first rainforests on Earth, emerging during the Upper Carboniferous, or Pennsylvanian, time period that extended from about 310 million to 290 million years ago.
. . A reconstruction of the ancient forest showed that like today’s rainforests, it had a layered structure with a mix of plants now extinct: Abundant club mosses stood more than 130-feet high, towering over a sub-canopy of tree ferns and an assortment of shrubs and tree-sized horsetails that looked like giant asparagus.
. . The scientists think a major earthquake about 300 million years ago caused the region to drop below sea level where it was buried in mud. They estimate that within a period of months the forest was buried, preserving it “forever”. Because the spatial layout of the forest has been maintained, the scientists can learn about entire plant communities, not just individual plants.
Apr 23, 07: Scientists have identified the Godzilla of fungi, a giant, prehistoric fossil that has evaded classification for more than a century, U.S. researchers said.
. . A chemical analysis has shown that the 6-meter organism with a tree-like trunk was a fungus that became extinct more than 350 million years ago. The giant fungus originally was thought to be a conifer. Then some believed it was a lichen, or various types of algae. Some suspected it was a fungus. "A 20-foot-fungus doesn't make any sense. Neither does a 20-foot-tall algae make any sense, but here's the fossil", C. Kevin Boyce, a U of Chicago assistant professor of geophysical sciences, said.
. . If Prototaxites were a plant, its carbon structures would resemble similar plants. Instead, Boyce found a much greater diversity in carbon content than would have been expected of a plant.
. . Fungi, which include yeast, mold and mushrooms, represent their own kingdom, neither plant nor animal. Once classified as plants, they are now considered a closer cousin to animals but they absorb rather than eat their food.
. . Samples of the giant fungi have been found all over the world from 420 million to 350 million years ago, during a period in which millipedes, bugs and worms were among the first creatures to make their home on dry land. No animals with a backbone had left the oceans yet. The tallest trees stood no more than a meter high, offering little competition for the towering fungi. Plant-eating dinosaurs had not yet evolved to trample Prototaxites' to the ground. "It's hard to imagine these things surviving in the modern world", Boyce said.
Apr 20, 07: They may all be black-hairy and they may all eat and act in much the same way, but chimpanzees from different parts of Africa are genetically more diverse than all of humanity, researchers reported.
. . Experts have long marveled that older ideas of race are not reflected in human DNA. Genetic diversity is more pronounced within population groups than between them, with only a few gene differences accounting for the wide variations seen in eye, skin and hair color across humanity.
. . So animals all about the same size and color and showing few behavioral differences must be even more genetically identical, right? Wrong, says Molly Przeworski, assistant professor of human genetics at the U of Chicago. Her team looked at the DNA of the three designated populations of chimpanzees in Africa --the eastern, western and central populations, designated by some researchers as sub-species of the chimpanzee. They found that a western chimpanzee has more differences, genetically, from an eastern chimp than any one human being has from another. "This gives us a working model of how human evolution might have proceeded", she said.
. . Millions of years ago in Africa, ancient remains indicate that several species of pre-humans emerged and lived perhaps side-by-side. Chimpanzees, the closest genetic living relative to human beings, may be undergoing changes similar to those that drove human evolution.
. . Przeworski's team also looked at bonobos, a separate species of chimpanzee. The chimpanzee genome differs from the bonobo genome by about 0.3%, which is one-fourth the distance between humans and chimps, they found. And yet bonobos are very different from the common chimpanzee. They are smaller, much gentler and known for their frequent sexual interactions.
. . The researchers say they estimate that bonobos, which live south of the Congo River, split off from the ancestors of modern chimpanzees about 800,000 years ago. Western chimps appear to have separated from central and eastern chimpanzees about 500,000 years ago, and central and eastern chimps would have divided from one another about 250,000 years ago.
Apr 18, 07: The branches of Earth's oldest tree probably waved in the breeze like a modern palm, scientists said, based on two intact tree fossils that help explain the evolution of forests and their influence on climate. "We've solved this long-standing puzzle", said Linda VanAller Hernick.
. . The 385-million-year-old fossils, which scientists believe are evidence of Earth's earliest forest trees, put to rest speculation about fossilized tree stumps discovered more than a century ago.
. . The forests were flourishing at an important juncture in the history of life of Earth, coming shortly before the appearance of the first vertebrates --four-legged amphibians-- that could live on dry land. The stumps in Gilboa were unearthed in 1870 when workers were blasting a quarry. Until now, scientists had never seen the tops of those trees. Hernick and museum colleague Frank Mannolini discovered an intact crown and part of a tree trunk in 2004 and a year later found a 8.5-meter trunk portion of the same species.
. . Pieced together, they represent Wattieza, a tree that looked like modern-day palm with a crown of fronds that grew up to 10 meters high and reproduced through spores. The fern-like trees are about 23 million years older than Archaeopteris, which Hernick said resembled a modern tree, with conventional branches. Instead of leaves, the Wattieza had frond-like branches with branchlets that resembled a bottlebrush.
. . The tree branches fell to the forest floor, providing a potential food source and shelter for living creatures, the researchers said. "This is a spectacular find which has allowed us to recreate these early forest ecosystems", said British researcher Christopher Berry of Cardiff U, who worked on the study.
. . Berry said the branches would have decayed, providing a new food chain for the bugs living below. "The rise of the forests removed a lot of CO2 from the atmosphere. This caused temperatures to drop and the planet became very similar to its present day condition."
Apr 18, 07: Since the human-chimp split about 6 million years ago, chimpanzee genes can be said to have evolved more than human genes, a new study suggests. The results, detailed the large brains, cognitive abilities and bi-pedalism.
. . Jianzhi Zhang of the University of Michigan and his colleagues analyzed strings of DNA from nearly 14,000 protein-coding genes shared by chimps and humans. They looked for differences gene by gene and whether they caused changes in the generated proteins.
. . Bakewell, Zhang and a colleague found that substantially more genes in chimps evolved in ways that were beneficial than was the case with human genes. The results could be due to the fact that over the long term humans have had a smaller effective population size compared with chimps.
. . So random events would play a more dominant role than natural selection in humans. Here is why: Under the process of natural selection, gene variants that are beneficial get selected for and become more common in a population over time. But genetic drift, a random process in which chance “decides” which alleles survive, also occurs. In smaller populations, a fortuitous break for one or two alleles can have a disproportionately greater impact on the overall genes of that population compared with a larger one.
. . Chance events could also explain why the scientists found more gene variants that were either neutral and had no functional impact or negative changes that are involved in diseases.
Apr 13, 07: UK scientists have said that they have produced the strongest evidence to date that termites are actually cockroaches. They said their research shows that termites no long merited belonging to a different order (Isoptera), but should be treated as a family of cockroaches.
. . The study examined the DNA sequences of five genes in the creatures, and found that termites' closest relatives were a species of wood-eating cockroaches. The team sequenced the DNA of five genes from 107 species of Dictyopera (termites, cockroaches and mantids) to develop a picture of the creatures' evolutionary history. They concluded that termites should be classified as a family (Termitidae) within the cockroaches' order (Blattodea).
Apr 13, 07: Researchers have decoded genetic material from a 68 million-year-old Tyrannosaurus rex, an unprecedented step once thought impossible. "The door just opens up to a whole avenue of research that involves anything extinct", said Matthew T. Carrano, curator of dinosaurs at the Smithsonian.
. . Matt Lamanna, a curator at the Carnegie Museum of Natural History in Pittsburgh, called the finding "another piece in the puzzle that shows beyond the shadow of a doubt that dinosaurs are related to birds."
Apr 13, 07: Many of the genes that cause diseases in humans can be found in macaque monkeys but not in our nearest relative, the chimpanzee, researchers reported in a study that sheds more light on what makes humans different.
. . A team of more than 170 scientists from around the world has sequenced the genome --the entire genetic map-- of the rhesus macaque, a monkey heavily used by medical researchers. They can use this information to "triangulate" their way through the genomes of primates --the family of mammals that includes humans, great apes and monkeys.
. . Humans and chimps split away from their common ancestor between 4 million and 7 million years ago, depending on the estimate. Macaques split off about 25 million years ago, so having their DNA map adds a new dimension when examining the genes.
. . While humans and chimps share about 98% of their DNA, macaques share about 93%.
. . Researchers have learned that where a gene ends up, physically, in the chromosomes affects its function. Jumping genes can cause inherited high cholesterol, also called familial hypercholesterolemia, breast cancer, hemophilia, and Tay-Sachs disease.
. . Macaques appear to have been exposed to more retroviruses than humans have. Retroviruses include the AIDS virus, and can make themselves a permanent part of an animal's DNA. This is important because macaques are widely used for testing AIDS vaccines and drugs. Most primates are immune to the AIDS virus but macaques can be infected with a related version called simian immunodeficiency virus, or SIV.
Apr 13, 07: Two new raptor dinosaur species have been unearthed in Mongolia, including one that ranks among the smallest non-avian dinosaurs ever discovered. Tsaagan was slightly larger than a turkey and its skull is one of the best preserved Dromaeosaurid skulls ever found.
. . Dromaeosaurs were agile, bipedal dinosaurs that lived in Asia and the Americas during the Cretaceous period. They were closely related to birds and many of them are even known to have had feathers. Dromaeosaurs are often called “raptors,” after Velociraptor. It lived about 80 million years ago.
. . Fragments of a jawbone from the second raptor, Shanag ashile, was found in the Oosh region of Mongolia. It lived about 20 million years before Tsaagan and was probably much smaller, about the size of a small raven.
Apr 13, 07: in Science journal: Protein extracted from 68 million-year-old T. rex bones has shed new light on the evolutionary link between dinosaurs and birds. The team says their technique could help reveal evolutionary relationships between other living and extinct organisms.
. . Researchers compared organic molecules preserved in the T. rex fossils with those of living animals, and found they were similar to chicken protein. The discovery of protein in dinosaur bones is a surprise --organic material was not thought to survive this long. The proteins are original organic material from the dinosaur's soft tissue, and not contamination, the scientists argue. They are by far the oldest such molecules extracted from fossils. The work builds on an earlier discovery of soft tissue --including blood vessels-- by Dr Schweitzer's team in the same, incredibly well-preserved Tyrannosaurus rex fossils.
. . When the scientists compared the protein sequence pattern to those of living animals in a database, it was found to be structurally similar to chicken collagen, and there were also similarities with frog and newt protein. Dr Schweitzer said the similarity to chickens was exactly what one would expect given the relationship between modern birds and dinosaurs."
Apr 11, 07: If trees grow on other planets, their leaves might be red, orange or yellow, and not only in autumn, scientists say. Two new studies find that the color of a planet's photosynthetic organisms depend on the type of star the world orbits and the makeup of its atmosphere.
. . "You have a particular spectrum which is affected by the star's surface temperature, but once that light comes down through the atmosphere, the atmosphere filters that radiation," said study team member Victoria Meadows of the Virtual Planet Laboratory (VPL) at Caltech.
. . For example, our Sun radiates most of its energy in the green part of the visible spectrum. But ozone molecules in the Earth's atmosphere absorb much of this green light energy, allowing other colors, especially red, to filter through to the ground. The researchers want to figure out what those alternative biosignatures might be. It's unlikely, for example, that plants on alien worlds will be blue.
Apr 10, 07: Ancient microbes might have used a molecule other than chlorophyll to harness the Sun’s rays, one that gave the organisms a violet hue.
. . Chlorophyll, the main photosynthetic pigment of plants, absorbs mainly blue and red wavelengths from the Sun and reflects green ones, and it is this reflected light that gives plants their leafy color. This fact puzzles some biologists because the sun transmits most of its energy in the green part of the visible spectrum.
. . “Why would chlorophyll have this dip in the area that has the most energy?” said Shil DasSarma, a microbial geneticist at the U of Maryland. After all, evolution has tweaked the human eye to be most sensitive to green light (which is why images from night-vision goggles are tinted green). So why is photosynthesis not fine-tuned the same way?
. . DasSarma thinks it is because chlorophyll appeared after another light-sensitive molecule called retinal was already present on early Earth. Retinal, today found in the plum-colored membrane of a photosynthetic microbe called halobacteria, absorbs green light and reflects back red and violet light, the combination of which appears purple.
. . Primitive microbes that used retinal to harness the sun's energy might have dominated early Earth. Being latecomers, microbes that used chlorophyll could not compete directly with those utilizing retinal, but they survived by evolving the ability to absorb the very wavelengths retinal did not use, DasSarma said. The researchers speculate that chlorophyll- and retinal-based organisms coexisted for a time. But after a while, the researchers say, the balance tipped in favor of chlorophyll because it is more efficient than retinal.
. . DasSarma admits his ideas are currently little more than speculation, but says they fit with other things scientists know about retinal and early Earth. For example, retinal has a simpler structure than chlorophyll, and would have been easier to produce in the low-oxygen environment of early Earth, DasSarma said. Also, the process for making retinal is very similar to that of a fatty acid, which many scientists think was one of the key-ingredients for the development of cells.
. . Lastly, halobacteria, a microbe alive today that uses retinal, is not a bacterium at all. It belongs to a group of organisms called archaea, whose lineage stretches back to a time before Earth had an oxygen atmosphere. Taken together, these different lines of evidence suggest retinal formed earlier than chlorophyll, DasSarma said.
. . Des Marais said an alternative explanation for why chlorophyll doesn’t absorb green light is that doing so might actually harm plants. “That energy comes screaming in. It’s a two-edged sword”, Des Marais said. “Yes, you get energy from it, but it’s like people getting 100% oxygen and getting poisoned. You can get too much of a good thing.”
. . Des Marais points to cyanobacteria, a photosynthesizing microbe with an ancient history, which lives just beneath the ocean surface in order to avoid the full brunt of the Sun. “We see a lot of evidence of adaptation to get light levels down a bit", Des Marais said. “I don’t know that there’s necessarily an evolutionary downside to not being at the peak of the solar spectrum.”
. . If future research validates the purple Earth hypothesis, it would have implications for scientists searching for life on distant worlds, the researchers say.
Apr 5, 07: A single gene makes some poodles purse-sized while allowing a Great Dane to look a pony in the eye, U.S. scientists reported in a finding that may shed light on human size differences and diseases.
. . Dogs vary dramatically in size, more so than any other mammal. The key to those differences appears to lie in a variant of the IGF1 growth gene. All small dogs in the study shared a short bit of DNA that reduced the output of the IGF1 gene, the team of 21 researchers found. Medium-sized and large dogs did not. The discovery is important because IGF1 --insulin-like growth factor 1-- is found in all dogs and other species, including humans.
. . By learning how genes control body size in dogs, the researchers believe they can gain an understanding about skeletal size in humans. It may also lead to a greater knowledge of the role genes play in diseases like cancer, in which the ability of regulate cell growth is lost.
. . Domestic dogs have come a long way since they branched off from the gray wolf more than 15,000 years ago. Years of selective breeding have produced giants like the mastiff, which can exceed 91 kg, all the way down to the Chihuahua, weighing in at no more than 2.7 kg.
Apr 3, 07: The eight bonobos at the Great Ape Trust of Iowa howled as they watched two trumpeter swans dip into a lake for the first time. Who can blame them? Not only will the apes get new neighbors, they'll get a chance to name the rare birds.
. . Swartz said after observing the swans, the bonobos could pick a name that they think reflects the birds' behavior. He said they'll either use a board that has symbols the apes associate with objects or choose names from a list researchers provide. The apes already use the board to communicate with humans to identify things like location, food and color.
. . Bonobos walk on two legs and are the most humanlike in appearance of the great apes. They have sophisticated language skills, a trait they'll demonstrate when asked to name the swans.
Apr 3, 07: Italian researchers have excavated the skeleton of a 4 million-year-old whale in the Tuscan countryside, a discovery that could help reconstruct the prehistoric environment of the sea that once covered the region, officials said. The 10 meter skeleton, dating to the Pliocene epoch, was found in almost perfect order, with only the jaw bones out of place.
. . Nearly all of Italy was once under water, and it is not unusual to find cetacean fossils in Tuscany. Fish and other sea organisms are believed to have lived off the whale's decomposing body for decades. Cioppi said researchers are cataloging the organisms for lab research.
Apr 3, 07: Also found among the bones were some shark teeth, leading researchers to believe that the whale was attacked just before it died. Cioppi said it was too soon to tell if the shark killed the whale.
Apr 3, 07: An underground den of dinosaurs now reveals the first evidence that at least one species of "terrible lizards" could burrow. The findings suggest dinosaurs could have endured extremes of heat or cold by finding shelter within dens of their own making. They also hint that such burrowing dinosaurs could have even survived the initial brunt of the K-T extinction some 65 million years ago.
. . This "bird-hipped" dino is a member of a large group called Ornithopids, which walked on their hind legs and left behind bird-like footprints showing spread out toes.
. . The burrow had tinier burrows into its walls "maybe occupied by insects or mammals or other small organisms", Varricchio said. "That gives us a neat window into the ecology back then."
Apr 2, 07: The remains of one of the earliest modern humans to inhabit eastern Asia have been unearthed in a cave in China. The find could shed light on how our ancestors colonized the East. Radiocarbon dates, obtained directly from the bones, show the person lived between 42,000 and 39,000 years ago.
. . The Tianyuan remains display diagnostic features of modern H. sapiens. But co-author Erik Trinkaus and his colleagues argue, controversially, that the bones also display features characteristic of earlier human species. The most likely explanation, they argue, is interbreeding between early modern humans emerging from Africa and the archaic populations they encountered in Europe and Asia.
. . He added that evidence from the animal world suggested two closely related species, which have been separate for less than two million years, could interbreed successfully when given the opportunity to mate. This view is controversial. Other palaeoanthropologists say that some of these features are simply retained from ancient African ancestors. And most genetic evidence gathered from present-day humans does not appear to support significant interbreeding between modern humans from Africa and archaics.
. . The person's age at death was estimated by how much the teeth had worn down. This put the individual in their late 40s or 50s.
Apr 2, 07: A team of anthropologists said their study of South Texas fossil deposits revealed evidence including ancient teeth that shows the area was home to numerous types of primates 42 million years ago.
. . They announced the discovery of three new genera and four new species of primates based on their examination of material removed from Lake Casa Blanca International State Park near Laredo. Cope said the genus the researches have focused on likely had a diet of leaves and foliage and weighed about a kg. Its closest living relative would probably be the tarsier primate that lives in the Philippines.
Mar 30, 07: The idea that Charles Darwin delayed publishing On the Origin of Species for 20 years for fear of ridicule is a myth, a new assessment claims. A Cambridge historian with access to Darwin's papers says there is simply no evidence to show the naturalist held back his evolution theory. Dr John van Wyhe says the scientist was just busy with other writings and also sporadically hindered by ill-health.
. . The long gestation was typical of the way Darwin worked. The naturalist's book on orchids was not published until 30 years after that research began; he published his earthworms book 42 years after first conceiving the idea.
Mar 28, 07: The planetisimal that smacked Earth 65 million years ago wiped out the dinosaurs and paved the way for mammals to dominate, but it took another 10 to 15 million years for the ancestors of today's mammals to really take over, scientists said.
. . While some mammals seized the day and diversified after the planetisimal crashed off the Yucatan peninsula, causing a mass extinction, they largely were evolutionary dead-ends, scientists said.
. . Researchers used DNA from some of the 4,500 species of mammals on Earth and fossils of extinct animals to devise a family tree tracing mammalian evolutionary history. Mammals from the major groups around today arose tens of millions of years before the planetisimal struck and survived the calamity. But they remained secondary to now-extinct mammal forms and did not start diversifying and asserting themselves until about 55 to 50 million years ago, the study found. "Instead, the mammals that seemed to benefit from the death of the dinosaurs belonged to groups that are wholly extinct these days", said Bininda-Emonds.
. . Most of the present-day groups of placental mammals arose between 100 and 85 million years ago during the Cretaceous Period, the last act of the Age of Dinosaurs, with the peak around 93 million years ago, the researchers said. Placental mammals give birth to live young and include rodents, carnivores, primates and hoofed mammals. Other types of mammals include marsupials, like kangaroos, and the very rare monotremes like the platypus that lay eggs.
Mar 25, 07: Twins can be identical, fraternal and apparently semi-identical, scientists now report. Researchers discovered twins who are identical on their mom's side of the equation but share only half their genes from dad.
. . Here's how it happened: Two sperm cells fertilized one egg -—an event assumed to be very rare—- then split into two embryos. Identical twins are created when one fertilized egg splits into two embryos. They share the same placenta and are always of the same sex. Fraternal twins result from two eggs being fertilized at the same time, each by a different sperm. Each has its own placenta, and they can be the same sex or not.
Mar 26, 07: Jane Goodall, 72, is in Chicago for a three-day conference billed as the first scientific meeting on how chimpanzees think —-not just how they behave. Goodall, who revolutionized research on primates during the 1960s when she studied them at close range in Tanzania. 30 researchers are presenting their work on chimps' apparent mental capacity for empathy, cooperative problem-solving and even deception. The current "Mind of the Chimpanzee" meeting has drawn 300 of the world's leading primatologists.
. . "When I began in 1960 there must have been at least a million chimpanzees across Africa in 25 countries", Goodall said. "We don't think there are more than 150,000 now.
Mar 23, 07: The arch of an eyebrow or the curve of a lip tells chimps a lot about each other, a finding that may give scientists new understanding about the evolution of human communication, researchers reported. Chimps are humans' closest relatives, with just a 1.23% difference between the genetic codes of people and chimps.
. . Human faces can be easy to read, but sometimes people must look in different places on the face to get an accurate picture. "What we know from humans is that even a single movement added to an expression can change the entire meaning", said Lisa Parr, director of the Yerkes National Primate Research Center. In humans, some expressions are hard to distinguish because they use similar facial muscles. Fear and surprise are two examples of this. Parr found the same to be true of chimps.
. . Using ChimpFACS, Parr made three-dimensional, anatomically correct cartoon images of different chimpanzee facial expressions --ranging from bared teeth to pout. Chimps were then taught a simple computer matching game using a joystick to manipulate a cursor. They were first shown an image of a chimp expression, such as a scream. Then, they were shown two new images and asked to match up the original expression.
. . A scream was the easiest expression for chimps to identify. They also found it was easiest to distinguish between a scream and a whimper.
Mar 23, 07: Research in Brazil has produced fresh evidence that primates may have something approaching human "culture". A scientist has observed capuchin monkeys banging stones together, apparently as a signalling device to ward off potential predators.
. . The researcher says the animals appear to be learning this skill from each other --and even teaching incomers to the group how it should be done. Only as they became more used to his visits over time did the stone-banging decrease. Captive monkeys released into the area to join the study animals appeared to learn to bang stones as well.
24 January, 2005: A water-loving mammal that lived 50 to 60 million years ago was probably the "missing link" between whales and hippos, according to a new analysis. Biologists have argued over the relationship between hippos and whales for a period of almost 200 years.
. . The study places whales firmly within the cloven-hoofed group of mammals known as Artiodactyla, which includes cows, pigs, sheep, antelopes, camels and giraffes.
Mar 21, 07: A new species of North American bamboo was recently discovered by Iowa State U and U of North Carolina botanists, making it the third known native species of the hardy grass in the United States. The "hill cane" was discovered in the Appalachian Mountains. It's different from the other two native species of bamboo, which were discovered more than 200 years ago, because it drops its leaves in the fall.
. . Hill cane, or Arundinaria appalachiana, grows only to about 2 meters, compared with the other North American species —river cane and switch cane— which each can grow much taller and thicker. There are 1,400 species of bamboo.
Mar 21, 07: The fossil remains of small dinosaurs that burrowed into the ground have been found by scientists in Montana, US. The 95-million-year-old bones are from an adult and two juveniles and were unearthed in a chamber at the end of a 2.1m-long sediment-filled tunnel. The researchers say the discovery is the first definitive evidence that some dinosaurs dug dens and cared for their young in such structures.
. . The adult would have been about 2.1m from nose to tail, with the major part of that (about 1.2m) being the tail itself. The estimated width of the animal fits neatly with the size of the tube it was digging (about 30cm;1ft in diameter).
. . What is left of the tunnel structure is sloping and has two sharp turns before ending in a chamber. The team says its architecture is similar to the dens of modern burrowers, such as the striped hyena, puffin and some rodents.
Mar 20, 07: Nuthatches appear to have learned to understand a foreign language — chickadee. It's not unusual for one animal to react to the alarm call of another, but nuthatches seem to go beyond that — interpreting the type of alarm and what sort of predator poses a threat. When a chickadee sees a predator, it issues warning call — a soft "seet" for a flying hawk, owl or falcon, or a loud "chick-a-dee-dee-dee" for a perched predator.
. . The "chick-a-dee" call can have 10 to 15 "dees" at the end and varies in sound to encode information on the type of predator. It also calls in other small birds to mob the predator.
. . Templeton had been studying chickadees and noticed their varying response to different alarm calls so he recorded them and watched the responses. He found the songbirds warned of greater danger from small, agile raptors such as the pygmy owl rather than something larger and less maneuverable, like the great horned owl.
. . Since chickadees and nuthatches live in many of the same areas and are similar in size, he decided to see how the nuthatches reacted to chickadee warnings. He placed speakers at the base of trees where nuthatches were present, but where there were no live chickadees, so their actions wouldn't tip off the nuthatches. When the recorded warning calls were played, he reports, the nuthatches reacted appropriately. He added, it appears to be learned behavior because the mobbing calls of the two songbird species are very different.
. . So, does it work the other way? Perhaps that's a project I should do", he said.
Mar 15, 07: More species develop in warm, tropical climates or cooler, temperate areas? It turns out the longtime answer —the tropics— may be wrong.
. . True, more different types of animals exist there than in places farther from the equator. New research suggests that is because tropical species do not die out as readily. Cooler regions have a higher turnover rate, with more species developing but also more becoming extinct. "It's a surprising result."
. . By analyzing the DNA of 618 mammal and bird species that lived in the past several million years, they were able to determine that new species develop more readily farther away from the tropics. "It would take one species in the tropics 3 to 4 million years to evolve into two distinct species, whereas at 60 degrees latitude (two-thirds of the way toward either pole), it could take as little as 1 million years", Weir said. It also raises the question of whether a more variable climate causes more rapid evolution.
The canine larynx is the closest to the human larynges that we know. [did that contribute to their domestication?]
Mar 14, 07: Scientists have unearthed a fossil of a mammal the size of a chipmunk --13 cm long and weighing about 30 grams-- that skittered around with the dinosaurs, with a key feature in the evolution of mammals --the middle ear bones-- fabulously preserved.
. . The mammal, named Yanoconodon for the Yan Mountains of northern China, lived 125 million years ago during the Cretaceous period, the third and final act of the Mesozoic era, sometimes called the Age of Dinosaurs.
. . Wednesday, The scientists said the unusual critter retrieved from a fossil-rich rock formation provides rare insight into a crucial element of mammalian evolution: ear structure that enabled highly sensitive hearing. Its body was shaped very oddly for a mammal --with an elongated torso and short, stubby limbs. "In a way, it's sort of a salamander-like body form in a mammal."
. . he scientists think Yanoconodon was nocturnal and ate insects. It lived in a lush environment with fresh-water lakes, early flowering plants and many other animals. These included a variety of dinosaurs.
. . Yanoconodon is particularly important because it displays an intermediate stage in the evolution of mammalian ear structure. Mammals possess hearing superior to all other vertebrates, and that trait has been fundamental to mammalian life. Many early mammals are thought to have adopted a nocturnal existence that kept them away from the multitudes of dinosaurs and other nasty beasts looking for an easy daytime meal.
. . Scientists long have searched for clues on the origins of mammalian ear structure. The first true mammals appeared about 220 million years ago, not long after the first dinosaurs, but the process of acquiring the anatomy of fully modern mammals took many more tens of millions of years. A sophisticated middle ear of three tiny bones called the hammer (malleus), the anvil (incus) and the stirrup (stapes), plus a bony ring for the eardrum (tympanic membrane), give mammals an acute sense of hearing.
. . Scientists believe these bones evolved from the bones of the jaw hinge in the reptiles from which mammals are thought to have evolved. Luo said the Yanoconodon provided a definitive piece of evidence of this evolution. Its ear bones are fully like that of modern mammals, but remain connected to the lower jaw, which is not the case with modern mammals.
Mar 14, 07: Birds may be able to fly vast distances without getting lost because of sensors in their beaks, according to a study. German scientists said they found tiny iron oxide crystals in the skin lining of the upper beak of homing pigeons, laid out in a three-dimensional pattern that might help the birds to read the earth's magnetic field. Similar iron-containing cells had been found in the beaks of robins, golden warblers and chickens.
Mar 13, 07: A yacht voyage that genome pioneer Craig Venter took around the world has turned up a startling array of new genes and new gene families, his team reported. Venter's team took regular samples of seawater as they traveled aboard the Sorcerer II yacht, which had been transformed into a scientific vessel. They have found genes that help microbes use the sun's energy in new ways, genes that help them use nitrogen and genes that protect organisms from ultraviolet light.
. . Venter's team said they had identified more than 6 million new proteins. They have not identified new organisms because in their unusual experiment, called the Global Ocean Sampling Expedition, they are looking only at the DNA of the tiny organisms they are sampling.
. . "We are starting to view the world in a gene-centered fashion", said Venter, one of the researchers who mapped the human genome in a project that wrapped up in 2000. "Our goal is actually to try and sort out evolution, working back to what organisms are there." He calls his approach "metagenomics."
. . One of the first things the expedition found was that these little floating organisms make proteorhodopsins --proteins that are also found in the human eye and detect colored light. Why would bacteria have eye proteins? Venter believes they can use energy from the sun, as plants do, but without photosynthesis.
. . "They are largely responsible for the atmosphere we breathe", Venter said. The ocean is also a huge carbon sink. This means it absorbs carbon from the CO2 in the air --to the tune of 100 billion tons a year. Tweaking this just might help make up for some of the CO2 buildup that human activity is causing, Venter said --although he did not go so far as to say it might reverse global warming.
. . Bacteria also provide unexpected sources of new antibiotics, Venter said. "Most microbes have developed defense mechanisms to try and kill other microbes." Scientists can study these often very complex mechanisms to design drugs, he said.
Mar 9, 07: For big beasts, dinosaurs like Tyrannosaurus rex sure had small genomes. Scientists estimated the size of the genome --the genetic composition of an organism-- for 31 species of dinosaurs and extinct birds, and found that the meat-eating types like T-rex had relatively small genomes.
. . While dinosaurs have been extinct for 65 million years, researchers at Harvard University in Massachusetts and the University of Reading in Britain studied cells from fossilized bones to extrapolate the size of their genomes. But don't worry, T-rex fans. Having a small genome doesn't imply inferiority. As the researchers noted, a lungfish has a bigger genome than a human.
. . Theropods --like Tyrannosaurus, Allosaurus and Deinonychus-- had very small genomes in the range of modern birds. But plant-eating dinosaurs known as Ornithischians --including the armored Stegosaurus, the horned Triceratops and Styracosaurus and the duckbilled Maiasaura-- had more moderately sized genomes in the range of today's lizards and crocodilians. The researchers did not focus on the genome of the massive long-necked dinosaurs known as sauropods, like Diplodocus.
. . The research indicated that the small genomes associated with birds --whose genetic composition is the smallest of any land vertebrates-- appeared very early in dinosaur evolution, roughly 230 million years ago.
Mar 5, 07: People have long wondered how cowbirds can get away with leaving their eggs in the nests of other species, who then raise the baby cowbirds. Why don't the hosts just toss the strange eggs out? Now researchers seem to have an answer —-if the host birds reject the strange eggs, the cowbirds come back and trash the place. "It's the female cowbirds who are running the mafia racket at our study site." They found that 56% of the nests where cowbird eggs were removed were later ransacked.
. . They also found evidence of what they called 'farming' behavior,' in which cowbirds destroyed a nest to force the host bird to build another. The cowbird then synchronized its egg laying with the hosts' 'renest' attempt. "Cowbirds parasitized 85% of the renests, which is strong supporting evidence for both farming and mafia behavior", Hoover said.
Mar 5, 07: A new study by German scientists of spiders' copulation techniques found that males leave part of their sex organ inside their female partner as a sort of "chastity belt" to deter rivals. "By breaking off parts of their intromittent organs inside a virgin female, males can reduce sperm competition and thereby increase their paternity success."
. . After setting the tone by shaking the female's web, the male has only seconds to have sex before the larger female kills him. In over 80% of cases, the tip of the male's genital organ breaks off inside the female.
Mar 5, 07: A spectacularly quirky creature with long, curved spines protruding from its armored body prowled the ocean floor half a billion years ago near the dawn of complex life forms on Earth. Scientists identified an ancient invertebrate they named Orthrozanclus reburrus from 11 complete fossils retrieved from Canada's fossil-rich Burgess Shale rock formation.
. . Orthrozanclus, about half an inch (one centimeter) long, lived about 505 million years ago during the Cambrian Period. The Cambrian was an important moment in the history of life on Earth and a time of radical evolutionary experimentation when many major animal groups first appeared in the fossil record. This proliferation of life is dubbed the "Cambrian Explosion".
. . Orthrozanclus had no eyes and no limbs and apparently moved along the ocean floor with a muscular foot, like a snail does, while dining on bacterial growths. It seems to have been built to prevent predators from turning it into a quick snack. It was covered in a shell and had almost three dozen long, pointy, curved spines sticking out from the edge of its body, and many smaller ones, too.
. . This group was related to present-day snails, earthworms and mollusks, which include snails, clams, squid and octopuses.
Feb 27, 07: In order to conserve valuable energy, snails essentially play a game of follow-the-leader, a new study finds.
. . Davies discovered the snails' reuse of trails by measuring the thickness of the mucus along the trails. Snails create trails of mucus to that help them glide across the ground, mainly in search of food or a partner, but making all that mucus uses up a lot of energy. "Snails expend a lot of energy, probably a third, creating mucus."
Feb 27, 07: A drink of milk was off the menu for Europeans until only a few thousand years ago, say researchers from London. Analysis of Neolithic remains, in Proceedings of the National Academy of Sciences, suggests no European adults could digest the drink at that time.
. . U College London scientists say that the rapid spread of a gene which lets us reap the benefits of milk shows evolution in action. The ability to drink milk gave some early Europeans a big survival advantage. "This is probably the single most advantageous gene trait in humans in the last 30,000 years." Today, more than 90% of people of northern European origin have the gene.
. . In order to digest milk, adult humans need to have a gene which produces an enzyme called lactase to break down lactose, one of the main sugars it contains. Without it, a drink of milk proves an uncomfortable experience, causing bloating, stomach cramps and diarrhea. In some parts of the world, such as Asia and Africa, the vast majority of people are lactose intolerant to some degree.
. . They looked for the gene that produces the lactase enzyme in Neolithic skeletons dating between 5480BC and 5000BC. These are believed to be from some of the earliest farming communities in Europe. The lactase gene was absent from the DNA extracted from these skeletons.
. . "Although the benefits of milk tolerance are not fully understood, they probably include the advantage of a continuous supply compared with the 'boom and bust' of seasonal crops, its nourishing qualities, and the fact that, unlike stream water, it's uncontaminated with parasites, making it safer.
Feb 23, 07: A new study, certain to be controversial, maintains that chimpanzees and humans split from a common ancestor just 4 million years ago --a much shorter time than current estimates of 5 million to 7 million years ago.
. . The researchers compared the DNA of chimpanzees, humans and our next-closest ancestor, the gorilla, as well as orangutans. They used a well-known type of calculation that had not been previously applied to genetics to come up with their own "molecular clock" estimate of when humans became uniquely human. "Assuming orangutan divergence 18 million years ago, speciation time of human and chimpanzee is consistently around 4 million years ago."
. . The theory of a molecular clock is based on the premise that all DNA mutates at a certain rate. It is not always a steady rate but it evens out over the millennia and can be used to track evolution. Experts have long known that humans and chimpanzees share much DNA, and are in fact 96% identical on the genetic level.
. . Experts agree that humans split off from a common ancestor with chimpanzees several million years ago and that gorillas and orangutans split off much earlier. But it is difficult to date precisely when, although most recent studies have put the date at somewhere around 5 million to 7 million years ago.
. . What they found directly contradicts some other recent research. They found evidence that it took only 400,000 years for humans to become a separate species from the common chimp-human ancestor.
. . Just last May, David Reich of the Broad Institute at the Massachusetts Institute of Technology and Harvard Medical School's Department of Genetics found evidence that the split probably took 4 million years to occur, although his team put the final divergence at just 5.4 million years ago. Reich's study of chimpanzee and human DNA suggested that the early ancestors of humans and the ancestors of chimpanzees may have interbred for a long time before they separated.
. . Their look at the molecular clock showed humans evolved one unique trait just a million years ago --our longer life span and our long childhood that means humans reach sexual maturity very late in life compared to other animals.
Feb 22, 07: Chimpanzees have been seen using spears to hunt bush babies, U.S. researchers said in a study that demonstrates a whole new level of tool use and planning by our closest living relatives. Perhaps even more intriguing, it was only the females who fashioned and used the wooden spears, Jill Pruetz and Paco Bertolani of Iowa State University reported. Bertolani saw an adolescent female chimp use a spear to stab a bush baby as it slept in a tree hollow, pull it out and eat it. Pruetz: "I saw the behavior over the course of 19 days almost daily." They'd watched the Fongoli community of savanna-dwelling chimpanzees in southeastern Senegal.
. . The chimps apparently had to invent new ways to gather food because they live in an unusual area for their species, the researchers report. "It is similar to what we say about early hominids that lived maybe 6 million years ago and were basically the precursors to humans." Chimps and humans split off from a common ancestor about 7 million years ago.
. . Chimps are known to use tools to crack open nuts and fish for termites. Some birds use tools, as do other animals such as gorillas, orangutans and even naked mole rats. But the sophisticated use of a tool to hunt with had never been seen.
. . The chimps choose a branch, strip it of leaves and twigs, trim it down to a stable size and then chew the ends to a point. Then they use it to stab into holes where bush babies might be sleeping. It is not a highly successful method of hunting. They only ever saw one chimpanzee succeed in getting a bush baby once.
. . Pruetz noted that male chimps never used the spears. She believes the males use their greater strength and size to grab food and kill prey more easily, so the females must come up with other methods. "That to me was just as intriguing if not even more so." Maybe females invented weapons for hunting, Pruetz said.
. . "The observation that individuals hunting with tools include females and immature chimpanzees suggests that we should rethink traditional explanations for the evolution of such behavior in our own lineage", she concluded in her paper.
. . "The multiple steps taken by Fongoli chimpanzees in making tools to dispatch mammalian prey involve the kind of foresight and intellectual complexity that most likely typified early human relatives." Researchers documented 22 cases of chimps fashioning tools to jab at smaller primates. They were using enough force to injure an animal that may have been hiding inside. The Fongoli chimpanzees carried out four or more steps to manufacture spears for hunting.
Feb 21, 07: Clever scrub jays can plan on saving tasty treats for the future and do it in a way that shows they are truly planning ahead, British researchers reported.
. . They set up a careful experiment to allow the birds to cache food in a certain way if they were indeed planning, and found the birds were up to the task. Their study adds to several others that show animals such as great apes and certain birds can plan ahead in much the same way as people do.
. . "We show that the jays make provision for a future need, both by preferentially caching food in a place in which they have learned that they will be hungry the following morning and by differentially storing a particular food in a place in which that type of food will not be available the next morning", they added.
. . Jays are members of a group of birds called corvids, which include crows, jays and ravens. Biologists consider them to be the most intelligent birds.
Feb 20, 07: A sharp freeze could have dealt the killer blow that finished off our evolutionary cousins the Neandertals, according to a new study. The ancient humans are thought to have died out in most parts of Europe by about 35,000 years ago.
. . And now, new data from their last known refuge in southern Iberia indicates the final population was probably beaten by a cold spell some 24,000 years ago. They say a climate downturn may have caused a drought, placing pressure on the last surviving Neandertals by reducing their supplies of fresh water and killing off the animals they hunted.
. . During the last Ice Age, the Iberian Peninsula was a refuge where Neandertals lived on for several thousand years after they had died out elsewhere in Europe. These guys (Homo neanderthalensis) had survived in local pockets during previous Ice Ages, bouncing back when conditions improved. But the last one appears to have been characterized by several rapid and severe changes in climate which hit a peak 30,000 years ago.
. . Southern Iberia appears to have been sheltered from the worst of these. But about 24,000 years ago, conditions did deteriorate there. This event was the most severe the region had seen for 250,000 years. The cause of this chill may have been cyclical changes in the Earth's position relative to the Sun --so-called Milankovitch cycles.
. . But a rare combination of freezing polar air blowing down the Rhone valley and Saharan air blowing north seems to have helped cool this part of the Mediterranean Sea, contributing to the severe conditions.
. . Gorham's Cave on Gibraltar shows evidence of occupation by groups of Neandertals until 24,000 years ago. But thereafter, researchers have found no signs of their presence. However, in an interesting new development, scientists are also now reporting another site, from south-east Spain, which has yielded evidence for the late survival of Neandertals. Sediment layers containing stone tools of a style known to have been made by Neandertals were found to date from 45,000 years ago until 21,000 years ago.
Feb 19, 07: Genetic tests of North American birds show what may be 15 new species including ravens and owls --lookalikes that do not interbreed and have wrongly had the same name for centuries, scientists said.
Feb 19, 07: Most species on Earth, including a number of bats, still fly under the radar of scientists, but a high-tech method that identifies animal species based on a snippet of DNA is starting to weed out concealed organisms.
. . Two studies found the method, called DNA barcoding, can reveal entire assemblages of species, including new genetically distinct bird and bat species. “In the future, we’re going to have kids walking through the forest with DNA barcoders, and they will walk up and pick a leaf or touch a frog and they’ll get to know what that organism is.” The use of the same gene for all species offers the benefit ofstandardizing the process and allowing for the creation of a “barcode catalog” of sorts.
. . Hebert likens the barcode to the string of digits stamped onto your soup can or cereal box that give away their exact identities with the sweep of a grocer’s scanner. “These unique barcodes rise through the process of evolution, through genetic drift and through selection.”
. . A library of species barcodes could be a huge time-saver, giving scientists in the field or on the road a handy reference to match a new specimen found in nature with its taxonomic information in a database. Traditional match-ups typically take months of microscope and even genetic analyses back at the lab before declaring something one species or another.
Feb 15, 07: The biggest general science conference in the world is shaping up to be unusually political this year, with an emphasis on global warming and sustainability. There's even a workshop on how scientists can fight anti-evolutionists on local school boards. "The purpose of science is to tell us about the nature of the world whether we like the answer or not", said Alan I. Leshner, CEO of the AAAS.
Feb 15, 07: A Mexican researcher announced the rare find of a tiny tree frog completely preserved in amber that he estimates lived about 25 million years ago.
. . The chunk of amber containing the 0.4-inch frog was uncovered by a miner in southern Chiapas states in 2005 and was bought by a private collector, who lent it to scientists for study.
Feb 13, 07: Bats, lauded for scooping up mosquitoes and other nasty pests but reviled for drinking blood and spreading rabies, now have another unpopular habit to live down --it appears they eat songbirds, scientists said.
. . Spanish and Swiss researchers said they had nailed down controversial evidence that one large species of bat preys on little birds as they migrate through the dark of night over the Mediterranean. They said giant noctule bats, large bats with an 18-inch (45-centimetre) wingspan, were eating mostly insects during the spring but appeared to have a diet heavy in bird meat during the autumn.
. . No other animal preys on birds that migrate at night, and this species of bat may have switched to this abundant food source recently. "In the course of a few million years, bats colonized most ecological niches and learned to exploit a wide array of food sources including arthropods, pollen, fruit, small terrestrial vertebrates and even blood."
. . It's hard to tell what is going on in the middle of the night high in the air over the sea, so they analyzed the blood of the bats. Chemical variants called isotopes can tell what an animal has been eating and carbon and nitrogen isotopes are especially useful for pinpointing the sources of a diet. They tested the blood of the bats throughout the year and found strong evidence that the flying mammals ate only insects in the summer, ate a few songbirds in the spring, and then preyed heavily on birds in the autumn.
. . "A big proportion of them are small-sized; as an example, more than 90 percent of migrating passerines mist-netted in the study area have an average body mass of less than 20 g (0.8 ounces).
Feb 13, 07: Enormous deep-sea squid emit blinding flashes of light as they attack their prey, research shows. Taningia danae's spectacular light show was revealed in video footage taken in deep waters in the North Pacific.
. . Japanese scientists believe the creatures use the bright flashes to disorientate potential victims. They say the squid are far from the sluggish, inactive beasts once thought. The footage reveals the creatures emitting short flashes from light-producing organs, called photophores, on their arms.
. . It could also act "as a means of illumination and measuring target distance in an otherwise dark environment." However, further investigation revealed the light bursts may also serve another, quite different, purpose away from the hunting field --courtship.
. . Larger species of giant squid belong to the Architeuthidae family: females are thought to measure up to 13m in length. But the aptly named colossal squid (Mesonychoteuthis hamiltoni) is thought to be the largest of all --possibly reaching up to 14m (46ft).
Feb 12, 07: Chimpanzees may have been using stone "hammers" as long as 4,300 years ago. An international research team, led by archaeologist Julio Mercader of the U of Calgary, Canada, said it had uncovered the hammers, dated to that time, in the West African country Ivory Coast. It would be the earliest known use of tools by chimpanzees.
. . The hammers were used to crack nuts, a behavior still seen in chimps in that area. The earliest reports of stone tool use by chimpanzees in this area date to the writings of Portuguese explorers in the 1600s.
. . The stones were about the size of cantaloupes with patterns of wear indicating use to crack nuts. The rocks would have been too large for human hands, but about right for the larger, stronger hands of chimpanzees, the researchers said. "It's not clear whether we hominins invented this kind of stone technology, or whether both humans and the great apes inherited it from a common forebear."
. . If chimps and early humans shared this technology with a common ancestor between 5 million and 7 million years ago, there should be sites with chimp debris going back 5 million years and the earliest human stone tool sites should show the kinds of debris found at the chimp sites, Ambrose said: "They absolutely do not."
. . Some of the hammers also had starch residue on them, mostly from types of nuts that are still eaten by chimpanzees, but not humans.
Feb 8, 07: Moth antennae contain gyroscope-like sensors to help them control their course through the air, scientists say. Up until now, the insects' wobble-free flight remained a mystery --especially because their love of low light meant they could not rely on visual cues. A US team found a structure at the base of the antennae that senses when the body starts to pitch or roll and relays this information to the brain.
. . They looked at what happened when the insects' antennae were removed. Monitoring the antennae-less moths in a dimly lit flying chamber, the team discovered the moths' flight was extremely unsteady: they collided with the walls, flew backwards or crashed to the floor. However, when the antennae were glued back on, the moths regained their agile grace.
Feb 7, 07: Humans have had an intimate relationship with the bacteria that causes painful stomach ulcers for more than 60,000 years, scientists said.
. . They traced the origins of a tummy bug known as Helicobacter pylori, which is also linked to stomach cancer, found it migrated out of Africa along with modern humans in their digestive system. "Humans and Helicobacter have evolved, or co-evolved, in a very intimate way with strains of bacteria having infected specific human populations for a very long time."
. . By using computer simulation they showed how the bacteria spread around the world. The genetic differences they found in the bacteria mirrored those that occurred in human populations as they left Africa. So the spread of humans and Helicobacter pylori paralleled each other.
. . Helicobacter pylori lives in the stomach and more than half of the world's population is infected with it. Although most people do not develop any illness, some develop ulcers in the stomach or a part of the small intestine known as the duodenum. Antibiotics are the usual treatment.
. . Balloux said the findings could reveal whether long co-evolution between a disease and the host leads to increased or decreased virulence.
Feb 6, 07: DNA tests carried out on two British men have shed light on a mystery surrounding the ancestry of Thomas Jefferson, America's third president.
. . In the 1990s, DNA was taken from male relatives of Jefferson to see if he fathered a son with one of his slaves. They found the president had a rare genetic signature found mainly in the Middle East and Africa. The Y chromosome is a package of genetic material passed down from father to son, more or less unchanged --just like a surname.
. . This DNA type has now been found in two Britons with the Jefferson surname. Genetic analysis showed the British men shared a common ancestor with Thomas Jefferson about 11 generations ago. But neither knew of any family links to the US.
. . This discovery scotches any suggestion that Jefferson --who was president between 1801 and 1809-- must have had recent paternal ancestors from the Middle East. Their study makes Jefferson's claim to be of Welsh extraction much more plausible.
. . The DNA sequences of individual K2s --including those from Europe-- are quite different from one another. This "genetic diversity" has to accumulate over time, supporting the idea K2 is not a recent introduction into Europe.
. . The haplogroup has probably been present for centuries in the "indigenous" population of western Europe, says Professor Jobling, and is not exclusive to the Middle East and Africa. It could have been introduced to Europe by the first modern humans to colonise the continent 40,000 years ago.
. . In 1998, Jobling and others completed an investigation looking at whether Jefferson, main author of the Declaration of Independence, fathered a son with Sally Hemings, a slave he owned.
. . Rumors had long existed that they had one or more children. Since Jefferson had no legitimate surname-bearing progeny, the team used samples from descendents of his paternal uncle. They compared these with descendents of Eston Hemings Jefferson, Sally's last son. The Y chromosomes matched, suggesting Jefferson, *or one of his paternal relatives, was Eston's father.
Feb 5, 07: Bacteria that kill off male butterflies can actually lead to increased promiscuity in female butterflies, scientists have found. The team discovered as the bacteria caused male populations to fall, females mated more frequently to boost their chances of becoming impregnated.
. . The study has revealed the bacteria's powerful effect on mating systems. The Wolbachia bacteria are passed from mother to son in some species of tropical butterfly, and kill the embryo before it hatches. The bacteria are so effective, some islands can be left with one male to every 100 females.
. . "As the male butterflies got less common, females mated more, when it should be harder to find a male." While most female butterflies are expected to mate once or twice in a lifetime, the team found females on the islands were mating three to five times. Dr Hurst added: "The remarkable thing is the species can survive with a ratio of 50 females to every one male."
Feb 5, 07: A French-led marine expedition team believes it has discovered thousands of new species of mollusks and crustaceans around a Philippine island. "It is estimated that 150-250 of the crustaceans and 1,500-2,500 of the mollusks are new species."
Jan 31, 07: Early humans could never have come into contact with the giant carnivorous "terror bird" Titanis walleri, research suggests.
It had been thought the fearsome beasts became extinct as little as 10,000 years ago --a time when humans shared their North American habitat. A US team has now revised this date to about two million years earlier.
. . T. walleri is thought to be the largest species of the terror bird family. It would have stood 2m tall and weighed 150kg. The flightless species, which inhabited South and North America, had an enormous beak and lived up to its terror tag by being a top predator of its time.
. . By analyzing the distribution of a group of chemicals, known as rare earth elements, within the bones, the team was able determine the age of the North American remains. "What we now believe, based on the age of the Titanis from Texas, is that Titanis dispersed from South America into North America about five million years ago, significantly earlier than the land bridge formed." The researchers did not yet know how it could have crossed unconnected continents.
Jan 29, 07: The tiny woman dubbed the Hobbit who lived 18,000 years ago on a remote Indonesian island deserves to be deemed a new human species and not a deformed modern human as skeptics assert, researchers said.
. . In the latest salvo in a heated scientific shootout, an international team led by Florida State U anthropologist Dean Falk compared the Hobbit's skull to those of nine people with microcephaly, a rare condition in which the head is abnormally small due to improper brain development.
. . They concluded the 1-meter-tall adult woman had a highly evolved brain, unlike that of a microcephalic person, confirming she belongs to the proposed extinct species Homo floresiensis, closely related to modern Homo sapiens. "Lo and behold, it doesn't look anything like a microcephalic. In fact, it's antithetical", Falk said.
Jan 24, 07: Archaeologists who found the remains of human "Hobbits" have permission to restart excavations at the cave where the specimens were found. "We'll probably be in there towards the middle of the year." Indonesian officials had blocked access to the cave since 2005, following a dispute over the bones --reportedly due to political sensitivities. "You've got to get there in the dry season."
. . The researchers claim that the remains belong to a novel species of human. But some researchers reject this assertion, claiming instead that the remains could belong to a modern human with a combination of small stature and a brain disorder.
. . Finding other specimens in the cave, particularly one with an intact skull, is crucial to resolving the debate over whether the Hobbit's classification as a separate species --Homo floresiensis-- is valid.
. . Skeletal remains were discovered by an Australian-Indonesian research team in Liang Bua, a limestone cave deep in the Flores jungle, in 2003. Researchers found one near-complete skeleton, which they named LB1, along with the remains of at least eight other individuals.
. . LB1 was an adult female who lived 18,000 years ago who stood just 1m tall and possessed a brain size of around 400 cc --about the same as that of a chimp. Long arms, a sloping chin and other primitive features suggested affinities to ancient human species such as Homo erectus and even earlier ones such as Homo habilis and Australopithecus.
. . Professor Teuku Jacob, based at Gadjah Mada U, in Indonesia, contended that the bones of LB1 could have been those of a pygmy person with the condition microcephaly, which is characterized by a small brain.
. . In 2004, Professor Jacob --known as Indonesia's "king of palaeoanthropology"-- took the bones away from their repository in Jakarta to his lab, 443km away, against the wishes of the researchers who found them. They were eventually returned. But the discoverers claimed the bones were extensively damaged in Jacob's lab during attempts to make casts.
Jan 24, 07: While people can't see ultraviolet light, spiders can, and it turns out to be important to their mating, researchers report. It seems that both male and female jumping spiders --Cosmophasis umbratica-- have markings on their faces and legs that glow in ultraviolet light.
. . Jumping spiders are known to have good eyesight, he said, adding that many of these spiders are colorful, with the males generally more colorful than females. "We conclude that sexual coloration is a crucial prerequisite for courtship."
Jan 24, 07: People of African origin have lived in Britain for centuries, according to genetic evidence. A Leicester U study found that seven men with a rare Yorkshire surname carry a genetic signature previously found only in people of African origin. The men seem to have shared a common ancestor in the 18th Century, but the African DNA lineage they carry may have reached Britain centuries earlier. One individual had no knowledge of any African heritage in his family.
. . Prior to the 20th Century, there have been various routes by which people of African ancestry might have reached Britain. For example, the Romans recruited from Africa and elsewhere for the garrison that guarded Hadrian's Wall.
. . Another major route was through the slave trade. "Some of the Africans who arrived in Britain through the slave trade rose quite high up in society, and we know they married with the rest of the population", said Ms King. This study further debunks the idea that there are simple and distinct populations or 'races'."
. . Genetic studies show that Thomas Jefferson's K2 haplogroup ultimately came from north-east Africa or the Middle East, the areas where it is most commonly found today.
Jan 24, 07: Marsupial lions, kangaroos as tall as trucks and wombats the size of a rhinoceros roamed Australia's outback before being killed off by fires lit by arriving humans, scientists said. The team discovered 69 species of mammals, birds and reptiles, including eight new species of kangaroo, some standing up to 3 meters tall.
. . Protected from wind and rain, and undisturbed due to their remote location, the remains of the mega-beasts are in near-perfect condition, including the first-ever complete skeleton of a marsupial lion, Thylacoleo carnifex.
. . Research into the fossils challenges recent claims that Australia's megafauna were killed off by climate change, pointing the finger instead at fires, probably lit by the first human settlers who transformed the fragile landscape.
. . The lands inhabited by the megafauna once supported flowers, tall trees and shrubs. But isotopes extracted from skeletal enamels show the climate was hot and arid, similar to today. The plants, the scientists said, were highly sensitive to so-called fire-stick farming, where lands were deliberately cleared by fires to encourage re-growth.
. . "Australian megafauna could take all that nature could throw at them for half-a-million years, without succumbing", said Richard Roberts, a geochronologist at the U of Wollongong. "It was only when people arrived that they vanished."
Jan 24, 07: An astonishing collection of fossil animals from southern Australia is reported by scientists. The creatures were found in limestone caves under the Nullarbor (no-tree) Plain and date from about 400,000-800,000 years ago. It appears the unsuspecting creatures fell to their deaths through pipes in the dusty plain surface that periodically opened and closed over millennia.
. . The palaeontological "treasure trove" includes 23 kangaroo species, eight of which are entirely new to science. The caves also yielded a complete specimen of Thylacoleo carnifex, an extinct marsupial "lion".
. . "To drop down into these caves and see the Thylacoleo lying there just as it had died really took my breath away."
Jan 24, 07: Flora, a Komodo dragon who has never mated or even mixed with a male, became a mother *and *father of five this week, British scientists said. Two fertilized eggs are still in an incubator.
. . Flora had fertilized the eggs herself without any male help, in a process culminating in parthenogenesis or "virgin birth." Other lizards can fertilize their eggs by parthenogenesis, but Buley and his team said it was the first time it has been shown that Komodo dragons, the world's largest lizards, can also accomplish it.
. . The baby dragons measured 40-45 cm and weighed up to 125 grams when they were hatched and are being cared for in a special area of the zoo where they have been feasting on a diet of crickets and locusts.
Jan 23, 07: Wasps fitted with miniscule radio tags have helped scientists shed light on the insects' behavior. Rather than just tending their home colonies, the worker wasps also buzzed into nearby relative-holding nests, helping raise the young, the team said.
. . The researchers believed the insects were boosting their chances of propagating their genes by nurturing relatives in multiple nests. A "staggering number", 56% of the population, were drifting from nest to nest. Worker wasps do not reproduce themselves, but by raising relatives --who share their genes-- they can pass on genes indirectly.
Jan 23, 07: About 125 million years before the Wright brothers embraced a similar design, a small feathered dinosaur took to the air with a biplane wing arrangement enabling it to glide from treetops, experts say. There has been a long-running debate over the origin of avian flight. It is widely believed among paleontologists that the first birds arose from small, feathered dinosaurs. Microraptor lived about 125 million years ago --roughly 30 million years before the earliest-known bird: Archaeopteryx.
. . The discovery of the tree-dwelling Microraptor in China was announced in 2003, but scientists writing this week in the journal Proceedings of the
National Academy of Sciences are offering a fundamental reassessment of how it flew.
. . Microraptor was a type of dinosaur known as a dromaeosaur and may be a relative of early birds. It was about 30 inches long from its head to the end of its lengthy tail, with a light, pigeon-sized body. Remarkably, it boasted two sets of wings --on the forelimbs and hind legs-- covered with feathers laid out in a manner similar to birds. It was a glider --like a flying squirrel-- apparently not capable of true flight.
. . The Chinese scientists who found Microraptor's beautifully preserved fossil proposed that when it glided between trees, it spread out its legs and kept its wings one behind the other in a tandem pattern much like a dragonfly. But using computer models and anatomical analysis, Chatterjee and aeronautical engineer Jack Templin found that this dragonfly arrangement would not work. In particular, they looked at the limb joints and feather orientation.
. . Chatterjee proposed that it positioned its hind legs below its body, adopting a biplane-like arrangement. It may have been able to glide over a distance of 40 meters. "Basically what happened is there is a transition from biplane to monoplane", Chatterjee said. "If you look at Archaeopteryx and all other birds, they have this typical monoplane design." Another small dinosaur known only from partial remains, Pedopenna, also may have used a biplane gliding approach, he said.
. . The researchers did acknowledge this biplane design may have been a failed evolutionary experiment that did not lead to birds. One theory is that birds evolved from little dinosaurs that were running and jumping from the ground. A competing theory is that birds evolved from small dinosaurs living in trees that initially used feathers to control their descent like a parachute, then glided through the forest canopy and eventually flapped their wings to achieve true flight. "This really settles once and for all that flight really evolved from trees down."
Jan 20, 07: A dazzling insect could help the development of brilliant white, ultra-thin materials, a study suggests. The finger-tip sized Cyphochilus beetle, found in south-east Asia, had a shell whiter than most other materials found in nature, UK researchers said.
. . Close inspection reveals a unique surface structure covered with scales 10 times thinner than human hair. The researchers found the beetle's shell was covered with ultra-thin scales, measuring just five micrometers (millionths of a meter), with highly random internal 3D structures. Usually animal color comes from pigmentation or carefully arranged structures (or both). Neither of those is very good for appearing white, because to look white something has to scatter every wavelength of visible light equally.
. . The team thinks the beetle evolved to be so white because the colour provides camouflage in amongst the white fungi common to where it is found.
. . These beetles have scales just 5 microns thick that act as 3-D photonic solids -—materials that manipulate light. Internally the scales are "a random network of interconnecting cuticular filaments." It's the randomness that does the job, apparently. Those filaments (in conjunction with the air gaps between them, says a good summary on Scientific American's web site today) bounce light around just right to have whiteness and brightness comparable to human baby teeth and treated paper.
Jan 20, 07: Scientists have uncovered for the first time secrets about how male seahorses produce their young that could prove valuable in conservation efforts to save the vulnerable species.
. . Unlike other animals and humans in which the female becomes pregnant, male seahorses carry their unborn in a pouch on their body and give birth to their young. They manage to reproduce very efficiently with small amounts of sperm and have a short window of opportunity in which to fertilize the female eggs. To overcome the lack of sperm, yellow male seahorses produce two types of sperm. "But even more surprising, the sperm they produce is expelled from their bodies into the sea water. But the sperm still manage to find the male pouch where the females have deposited the eggs."
. . All the female seahorse has to do is produce the eggs and transfer them to the pouch --a process that takes 5-10 seconds. The sperm also have to find their way into the pouch in that time because once the eggs are transferred the pouch closes and is sealed. Seahorses give birth to about 100. "If they have only a few hundred sperm and are producing a hundred offspring that is amazing in the world of sperm", Holt added.
Jan 18, 07: As it takes more energy to catch a large prey than a small one, and that a carnivore size cannot really exceed one ton. Apparently, life was easier for herbivores who were able to reach 30 tons or more.
. . The result gives a fresh perspective on why large carnivores are particularly vulnerable to extinction, and brings more bad news for polar bears. Not only is the arctic ice melting beneath them, but today's largest land carnivore also lives on a metabolic precipice, barely able to catch enough food to support its bulk.
Jan 16, 07: A 40,000-year-old skull found in a Romanian cave shows traits of both modern humans and Neandertals and might prove the two interbred, researchers reported.
. . If the findings are confirmed, the skull would represent the oldest modern human remains yet found in Europe. The study will add to the debate over whether modern Homo sapiens simply killed off their Neandertal cousins, or had some intimate interactions with them first.
. . DNA samples taken from Neandertal bones suggest there was no mixing, or at least that any Neandertal genetic contribution did not make it to the modern DNA pool.
. . Neandertals were also once designated Homo sapiens, although are a designated subspecies --Homan sapiens neanderthalis. But some experts now designate them as a separate species-- Homo neanderthalis.
Jan 11, 07: It's the world's biggest flower, and maybe the stinkiest, too. And now scientists have used genetic analysis to solve the long-standing mystery of the lineage of the rafflesia flower, known for its blood-red bloom measuring 1 meter wide and its nauseating stench of rotting flesh.
. . A team of researchers said rafflesia --discovered in an 1818 scientific expedition to a Sumatran rain forest-- comes from an ancient family of plants known not for big flowers, but for tiny ones. In fact, many of its botanical cousins boast flowers just a few millimeters wide. This family, called Euphorbiaceae, also includes the poinsettia, Irish bells and crops such as the rubber tree, castor oil plant and cassava shrub.
. . It is sort of a botanical outlaw --a parasitic plant that steals nutrients from another plant while deceiving insects into pollinating it.
. . Rafflesia (pronounced rah-FLEEZ-ee-ah) lives inside the tissue of a tropical vine related to the grapevine, with only its flower visible. It is devoid of leaves, shoots and roots, and does not engage in photosynthesis, the process plants use to exploit the energy from sunlight.
. . Its flowers can weigh 7 kg. They are a blotchy blood red. They smell like decaying flesh. And they even can emit heat, perhaps mimicking a newly killed animal in order to entice the carrion flies that pollinate it.
. . Davis said its lineage dates back roughly 100 million years to the Cretaceous Period, the last act of the Age of Dinosaurs when flowering plants are believed to have first appeared. The researchers determined that over a span of 46 million years, rafflesia's flowers evolved a 79-fold increase in size before assuming a slower evolutionary pace.
. . Recent efforts to nail down plant lineages have relied on molecular markers in genes relating to photosynthesis, but that was not possible with rafflesia. The researchers had to scour other parts of its genome for clues.
Jan 11, 07: An ancient skull from South Africa and carved tools and ornaments from Russia paint a rare picture of the time when modern humans migrated out of Africa to colonize Europe, researchers reported. The two reports link the far reaches of Europe to southernmost Africa across a short time span of 36,000 years ago to 45,000 years ago.
. . "The big surprise here is the very early presence of modern humans in one of the coldest, driest places in Europe", said John Hoffecker, of the U of Colorado-Boulder's Institute of Arctic and Alpine Research.
. . "It (Russia) is one of the last places we would have expected people from Africa to occupy first", Hoffecker said. "Current interpretations of the human fossil record indicate that fully modern humans emerged in sub-Saharan Africa by 195,000 years ago", Goebel wrote. "By 35,000 years ago, modern humans thrived at opposite ends of Eurasia, from France to island southeast Asia and even Australia. How they colonized these and other drastically different environments during the intervening 160,000 years is one of the greatest untold stories in the history of humankind."
. . They re-examined a skull discovered in 1952 near Hofmeyr, South Africa. It looked much more modern than other African skulls but it had been hard to date. The researchers used a combination of advanced optical and uranium methods to date the skull to about 36,000 years ago.
. . This was key, because few human fossils have been found in sub-Saharan Africa that date to between 70,000 and 15,000 years ago. Plenty of sophisticated stone and bone tools and artwork can be found, and fossils have been found in northern Africa and nearby areas of Asia and Europe --but little from the birthplace of humanity itself.
Jan 10, 07: Birds with bigger brains like crows and parrots survive better than their dimmer feathered friends, according to a study. Scientists have suspected that birds with large brains in relation to their body size lived longer because they were able to adapt their behavior and cope with environmental challenges. Crows, ravens and parrots have the largest brains while pheasants have a relatively small brain.
. . Earlier studies have shown there is a relationship between the size of the brain and an animal's capacity to create new behaviors and adapt more easily.
. . Studies of primates have produced similar findings.
Jan 8, 07: Baby tropical fish, drifting at the mercy of ocean currents, probably follow their noses back to their home reefs when they grow large enough to swim, researchers said. In their first few weeks of life, lacking the ability to swim, larval fish can drift up to 20 miles from where they were born. They likely rely on their sense of smell to make their way back home, according to scientists.
Jan 8, 07: The ability to grow like a weed may be an advantage when it comes to coping with climate change. Plants with short life cycles can adapt more quickly to change than those that reproduce slowly, according to a new study by researchers at the U of California.
. . "Some species evolve fast enough to keep up with environmental change. Global warming may increase the pace of this change so that certain species may have difficulty keeping up. Plants with longer life cycles will have fewer generations over which to evolve."
. . In a separate paper in the same issue, researchers report that amphibians such as salamanders and frogs appear able to adapt rapidly to changes in the environment. Kim Roelants of Vrije U in Brussels, Belgium, and colleagues report that they found no major extinctions of amphibians in a study of the fossil record of periods when other land animals were undergoing major extinctions. Instead, their analysis showed periods when amphibians diversified rapidly, an indication that they coped with change by changing themselves, rather than by dying out.
.
If you got here from the GAIA HOME PAGE, click on
"minimize" or "eXit". (upper right browser buttons)
If you didn't: the site.)