EVOLUTION & GENETIC NEWS, Gaia Church
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EVOLUTION
& GENETIC
NEWS '05
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See 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.
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.NEWS
Apr 1st, 05 thru Dec, 05.
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Dec 28, 05: Australia's Taipan, with a toxin 50 times as potent as the Indian cobra, is a serious contender for title of the world's deadliest snake.
Dec 27, 05: The apocryphal tale that you can't grow new brain cells just isn't true. Neurons continue to grow and change beyond the first years of development and well into adulthood, according to a new study. The finding challenges the traditional belief that adult brain cells, or neurons, are largely static and unable to change their structures in response to new experiences.
. . The study, performed in adult mice, found that the branch-like projections on some neurons, called "dendrites", were still physically malleable. Dendrites conduct electrical signals received from other neurons to the parent neuron's cell body. The changes occurred both incrementally and in short bursts, and involved both growth and shrinkage.
. . Some of the changes were dramatic by neuron standards. One dendrite sprouted an impressive 90 microns (about .003 inches), more than doubling its length in less than two weeks. "The scale of change is much smaller than what goes on during the critical period of development, but the fact that it goes on at all is earth-shattering", said study co-author Elly Nedivi.
. . During the early years following birth, humans manufacture an estimated 250,000 neurons per minute and then spend the next few years wiring them together. Traditionally, it was assumed that this neural plasticity settles down by adulthood.
. . In order to see directly into the brain, the researchers implanted glass windows over two areas of the visual cortex while the mice were still young.
Dec 26, 05: When male Asian elephants enter their annual period of heightened sexual activity and aggression, they broadcast their availability to the ladies by pumping out a pungent mix of pheromones. This mating period is called musth (pronounced "must").
. . But older males have the upper hand on their younger, less experienced competition, producing a more attractive mix of scents, a new study shows. Researchers analyzed more than 100 secretion samples from six males and found that this pheromone, called frontalin, exists in two mirror-image molecular forms designated as "plus" and "minus."
. . When teenage males start producing frontalin, they produce mostly the plus version. As they age, though, they begin secreting more of the minus pheromone, which smells bitter and acrid to humans. With maturity comes a mixture of the two forms. By the time they reach their mid 20's, adult Asian elephants have perfected a 1:1 mixture. Female pachyderms love it. Ovulating females were attracted to the 1:1 mixture, but non-reproductive and pregnant females weren't interested. And none of them were impressed by the immature samples.
Dec 22, 05: Common honey bees can be trained to recognize individual people, according to a paper published by Dr. Adrian Dyer in the Journal of Experimental Biology.
. . The training consisted of showing the bees a series of black-and-white pictures of human faces. The bees got tasty or sour rewards, depending on their performance. The face series is exactly the same one used by psychologists to test human memory.
. . How do bees do it? Bee brains are just one-twenty thousandth the size of a human brain. The experiment implies that there is a simpler solution to the problem of face recognition than has been discovered so far by biometric security researchers.
Dec 21, 05: Scientists have pieced together part of the genetic recipe of the extinct woolly mammoth. The 5,000 DNA "letters" spell out a large chunk of the genetic code of its mitochondria, the structures in the cell that generate energy.
. . The research, published in the online edition of Nature, gives an insight into the elephant family tree. It shows that the mammoth was most closely related to the Asian rather than the African elephant. The three groups split from a common ancestor about six million years ago, with Asian elephants and mammoths diverging about half a million years later.
Dec 22, 05: Mammoths became extinct in the last few thousand years, but scientists have pieced together part of the genetic recipe of the extinct woolly mammoth. The 5,000 DNA letters spell out a large chunk of the genetic code of its mitochondria, the structures in the cell that generate energy. It is the longest stretch of DNA [decoded to date] from any Pleistocene species.
. . The research gives an insight into the elephant family tree. It shows that the mammoth was most closely related to the Asian rather than the African elephant. The three groups split from a common ancestor about six million years ago, with Asian elephants and mammoths diverging about half a million years later. "We have finally resolved the phylogeny of the mammoth which has been controversial for the last 10 years", lead author Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said.
. . Mammoths lived in Africa, Europe, Asia and North America between about 1.6 million years ago and 10,000 years ago during the Pleistocene epoch. The woolly mammoth, Mammuthus primigenius, with its covering of shaggy hair, was adapted to the extremes of the ice ages.
. . The team of researchers --from Germany, the UK, and the US-- extracted and analysed mammoth DNA using a new technique that works on even the tiny quantities of fossilised bone - in this case 200 milligrams.
. . Some 46 chunks of DNA sequence were matched up and arranged in order, giving a complete record of the mammoth's mitochondrial DNA --the circular scrap of genetic material found outside the cell's nucleus.
. . The complete mitochondrial DNA of an extinct animal has been sequenced before but only for the flightless bird, the moa, which died out about 500 years ago.
. . In a separate piece of research, published in the journal Science, a team reports sequencing some of the nuclear DNA from 27,000-year-old Siberian mammoth remains. Again, novel techniques were used to get at this genetic material which is normally less prevalent than mitochondrial DNA.
. . The work shows the ice age beast to have been more closely related to the African elephant; its genetic material was 98.5% identical to nuclear DNA from an African elephant, the group said.
. . "What determines the physiology and the appearance of an organism is all stored in the chromosome [found in the nucleus], and so this tiny bit of information [carried by mitochondrial DNA] is only one-100,000th of the information that is stored on the chromosome."
Dec 21, 05: When the Sun stays up around the clock during the Arctic summer, the reindeer ditch their daily routines for a life cycle that better suits constant daylight. Animals and plants normally set their biological clocks by the rising and setting of the Sun. In humans, this internal rhythmic cycle organizes when we wake up, when we're most active, and when the pillow beckons.
. . In the very far North, however, the Sun is up for six months and then down for six months, creating days of either 24-hour light or darkness. Many animals can maintain their internal rhythm if the change is abrupt, such as when a migratory bird flies to a region with longer hours of daylight. But fewer can keep it ticking when light fades in or out gradually, as it does when seasons change in the Arctic. "This requires a 'strong' biological clock, one that is able to run on its own."
. . Stokkan's team monitored the daily feeding and movement of two reindeer species living at different latitudes—mountain reindeer Rangifer tarandus tarandus on mainland Norway (70 degrees North) and Svalbard reindeer. The reindeer spend 18 weeks a year, in autumn and spring, with a marked day/night cycle. During these few weeks, both species more or less follow the rhythm of a 24-hour day, Stokkan said. During the summer months, however, they developed a total lack of daily rhythm. The Svalbard reindeer lacked behavioral rhythm in winter as well.
. . With no internal clock to run their day, Stokkan posits the animals likely take infrequent naps of various durations, alternating between stretches of activity.
. . Having a weak biological clock seems to have benefits. Activity in the winter and summer appears driven more by their digestive system than sunlight, and the reindeer feed whenever the weather permits. This eating pattern is optimal for the microbial-assisted digestion typical of reindeer and other hoofed animals.
. . Reducing the influence of the internal clock may also enhance the animals' responsiveness and speed of adaptation.
Dec 21, 05: A study of gorillas at 17 North American zoos, led by Chicago's Brookfield Zoo, is the first to document gorilla menopause. The findings may help zoos improve how they care for aging female gorillas and change the way evolutionary biologists think about menopause in humans.
. . Many biologists believe menopause evolved because it gave human grandmothers more time to help care for their grandchildren. The new findings argue against the so-called "grandmother hypothesis", because female gorillas in the wild migrate away from their family groups and don't hang around to care for the grandkids.
. . Instead of an evolutionary adaptation, menopause could result merely from humans —-and captive gorillas-— living longer.
Dec 21, 05: A new study of genes in humans and chimpanzees pins down with greater accuracy when the two species split from one. The evolutionary divergence occurred between 5 million and 7 million years ago, an estimate that improves on the previous range of 3 million to 13 million years.
. . Modern chimps are the closest animal relative to humans. Knowing when the two split has implication both for understanding how quickly evolution works and for imagining the likelihood of intelligent beings elsewhere in the universe
. . Kumar’s team used a recently developed method in genetic sequencing to make the most comprehensive comparison to date of genes from humans, chimps, macaque monkeys and rats. They examined the number of mutations in the DNA sequence of each species to estimate its rate of evolutionary change.
. . The results were released today in the online version of the Proceedings of the National Academy of Sciences.
Dec 21, 05: Researchers at the University of Michigan have found a "pleasure spot" in the brains of rats that may shed light on how food translates into pleasure for humans. The spot in rats' brains makes sweet tastes more "liked" than other tastes, biopsychology researchers Susana Pecina and Kent Berridge found. Sweetness by itself is merely a sensation, they note. Its pleasure arises within the brain, where neural systems actively paint pleasure onto the sensation to generate a "liking" reaction.
. . The study pinpointed a pleasure spot within a larger part of the brain responsible for appetite in the nucleus accumbens, the lower front of the brain. "There's a liking cube tucked within a larger wanting cube."
. . The researchers used sweet things in their study, but Berridge noted the reaction would be the same with any liked food.
Dec 21, 05: The basic molecules of life are scattered through the universe, collecting in faraway galactic clouds, on passing comets and asteroids, and on the planets here in our solar system. But scientists still don't know how these molecules came to be, or how they originally came together to form life. Now, for the first time ever, astronomers have found some of the basic compounds necessary to build organic molecules and proteins found in DNA within the inner regions of a planet-forming disk. The object--IRS 46--is located in the Milky Way galaxy, about 375 light years away.
. . The researchers detected two organic compounds --acetylene and hydrogen cyanide-- in amounts nearly 10,000 times higher than found in the cold interstellar gas where stars are born. These compounds are commonly found in the atmospheres of the giant gas planets in our solar system, the icy surfaces of comets, and the atmosphere of Saturn's largest moon, Titan. They also detected carbon dioxide, which is widespread in the atmospheres of Venus, Earth, and Mars.
. . The presence of gas-rich disks around young stars is well known, but little is understood about their chemical structure. The discovery of acetylene and hydrogen cyanide in one of these disks will help astronomers better understand them and where future planetary systems may someday form and possibly result in life.
. . "If you add hydrogen cyanide, acetylene and water together in a test tube, and give them an appropriate surface on which to be concentrated and react, you'll get a slew of organic compounds including amino acids and a DNA purine base called adenine."
Dec 16, 05: another twist in the long-running debate about how dinosaurs regulated their body temperature. Most scientists believe that dinosaurs were warm-blooded and, as such, grew steadily according to a fixed genetic blueprint, rather than relying on warmth and food from the environment.
. . The plateosaur appears to be an intermediary form, somewhere between cold-blooded reptiles and warm-blooded mammals and birds. According to Martin Sander, the most likely explanation is that warm-bloodedness evolved several times in the history of the dinosaur and was not inherited from a common ancestor.
Dec 15, 05: A little striped fish has helped scientists begin to solve one of the biggest mysteries in biology --which genes are responsible for differences in human skin, eye and hair color. The large, international team of scientists reported that they had found a gene that makes African zebrafish of a lighter-than-normal color --and say the same gene helps explain the light-colored hair, skin and eyes of many Europeans.
. . While they stress that they have not found a genetic basis for race, they say just a tiny change in a single amino acid plays a major role in causing the distinctive light European coloring.
. . The gene is called SLC24A5. "Our results suggest that SLC24A5 explains between 25 and 38% of the European-African difference in skin melanin index", they wrote in the journal Science. Cheng's team was originally looking for genes involved in cancer. In people of European descent, pigment granules called melanosomes are fewer, smaller, and lighter than those from people of West African ancestry. The melanosomes of East Asians fall in between.
. . Scientists know that more than 100 genes are involved in pigment production, so the process is complex. But most of the genes identified so far are found in unusual conditions such as albinism. All vertebrates have a version of the gene. They found that one version appears to be the "base" version and is found in most people of African and East Asian descent. Europeans have a mutant version that differs by only a few letters of the genetic alphabet.
Dec 15, 05: A species of army ant (Cheliomyrmex andicola): What makes Cheliomyrmex such a fearsome predator is that its workers have claw-shaped jaws that are armed with long, spine-like teeth. These teeth may help Cheliomyrmex workers attach themselves to their prey's skin during attack. The ants' stings were particularly painful and itchy, comparable to the stings of fire ants. They believe the venom in a Cheliomyrmex sting is toxic and possibly paralytic, considering how quickly the giant earthworm became immobile after being attacked.
. . Based on an observation of the ants feeding on a snake, the researchers said the species is the only known New World army ant to remove and consume vertebrate flesh. Raiding parties of other New World army ants occasionally sting and kill small vertebrates such as lizards, snakes and birds, but do usually not consume them.
. . Cheliomyrmex is related to Old World driver ants in Africa, which also have large-toothed jaws and feed on large-bodied prey. The ancestor of Cheliomyrmex may have split from Old World army ants as long as 105 million years ago, at around the time when Africa and South America separated.
. . Cheliomyrmex lives mainly underground in New World tropical rainforests. Although previously identified, little was known about its behavior or prey.
Dec 15, 05: New photos show some squid moms carry 3,000 developing embryos around for up to nine months. Gonatus onyx is one of the most abundant species of squid in the Pacific and Atlantic Oceans and is an important food source for many predators. They spend most of their lives in shallow waters but dive to great depths to lay eggs. Because of this, scientists had never observed this squid's reproductive habits until recently, when they discovered that the secretive world of G. onyx reproduction is quite unlike anything they've seen before. "It's a shallow-living squid for most of its life, but then it dives down to 2,500 meters, lays 2,000 to 3,000 eggs, and carries them around for months."
. . Normally, squid propel themselves through the ocean by extending their arms outwards and snapping them back together. But, this technique doesn't work so well when you're delicately clutching 3,000 developing embryos between your arms. Aggressive swimming shook the mass and caused some of the eggs to fall off. To prevent losing eggs, the squid use their mantle and fins to move through the water.
. . "Deep-sea species have fewer eggs, but their offspring are larger and more capable of capturing prey", Seibel said. "But in order for the offspring to survive, the parent must provide care for them for six to nine months." Also, deeper water is relatively free of predators—predatory mammals don't frequent depths below 1,500 meters—making survival easier for both the 1/10th-inch hatchlings and their brooding mothers.
Dec 14, 05: Stone tools found embedded at the base of cliffs in southeastern England show that early humans lived in northern Europe 700,000 years ago --much earlier than previously thought, scientists said today.
. . Early humans were known to have inhabited the warmer parts of southern Europe 780,000 years ago but researchers thought they had not ventured across the Alps into the north for about another 200,000 years.
. . Although no human remains have been found in the sediment at the Pakefield site near Lowestoft, Suffolk, the researchers said the workmanship of the crude tools have all the hallmarks of being made by humans.
. . Southeast England 700,000 years ago would have been very different from today. Early humans probably lived along flood plains of large rivers that have since been destroyed by glaciers. They shared their habitat with creatures such as saber tooth cats, lions, giant deer, extinct mammoths and straight-tusked elephants.
. . The tools, which were used as knives and saws, were preserved in almost pristine condition in the sediment by glaciers. Stringer said the early humans who made them were probably stocky in build and meat-eaters.
Dec 14, 05: A gene known to be important for brain development is more active in humans than in apes, a discovery that might have played a key role in human evolution. The gene is used by cells to make an opiate-like protein found in apes and humans called "proydnorphin", or PDYN.
. . In humans, PDYN is believed to be important for perception, memory and susceptibility to drug dependence. People who don’t make enough of the protein are vulnerable to drug addiction, schizophrenia, bipolar disorder and a form of epilepsy, studies have found.
. . The researchers found that humans possess a distinctive variant in a regulatory segment of the gene that causes PDYN to be produced in higher concentration than in apes.
. . Altering the regulatory segments of a gene is often a better way to generate variability than altering the structure and function of a protein through random mutations, Wray said. Called "promoters", these regulatory segments determine how much and how fast a protein is expressed rather than change its structure or function.
. . The finding supports a growing consensus among evolutionary anthropologists that hominid divergence from the other great apes was fueled not by the origin of new genes, but by the speeding up or slowing down of the expression of existing genes.
. . The researchers didn’t find significant mutational changes in the parts of the PDYN gene that controlled protein structure or function. Instead, most of the changes were in segments of the gene that controlled the regulation of PDYN. For example, the PDYN protein is identical in chimps and humans, but the human version is 20% more active.
. . The researchers also found a surprisingly large amount of genetic variation in the PDYN promoter segment among humans. The analyses showed higher differences between the different populations—which included Chinese, Papua New Guineans, (Asian) Indians, Ethiopians, Cameroonians, Austrians and Italians -—than within them. Such a pattern is a signature of evolutionary selection, Wray said.
. . Still mysterious, however, is how the prodynorphin gene changes affect human neural development. "We do know that not making enough prodynorphin causes clinical problems, but we don't know what having more of it did for us humans."
Dec 14, 05: An animal behaviorist says she's figured out what dogs are doing when they make that excited panting noise while playing or anticipating a much desired walk. They're laughing.
. . Patricia Simonet, development and program coordinator for Spokane County Regional Animal Protection Service, also found that the sound of dog laughter comforts other dogs. When she played a recording of "play panting" through the speaker system at a shelter in Spokane Valley, all the barking dogs quieted within a minute.
Dec 14, 05: For hundreds of years, the purpose of the tusk on the narwhal, or "unicorn" whale, has stumped scientists and Inuit elders alike. It is an evolutionary mystery that defies many of the known principles of mammalian teeth.
. . A new study suggests the whales use their tusks to determine the salinity of water and search for food. And males may rub them together for as-yet unknown sensations.
. . Narwhals range from 4 to 5 meters and weigh between 1,000 and 1,400 kg. Many have an 2.5-meter-long tooth, or tusk, emerging from the left side of the upper jaw. The tooth's unique spiral, the degree of its asymmetry to the left side, and its odd distribution among most males and some females are all unique expressions of teeth in mammals. There is no known comparison in nature and certainly none more unusual in tooth form, expression, and functional adaptation.
. . The narwhal's tooth, while seemingly rigid and hard, has remarkable sensor capabilities. With ten million tiny nerve connections tunneling from the central nerve of the tusk to its outer surface, the thing is like a membrane with an extremely sensitive surface and can detect changes in water temperature, pressure, and particle gradients.
. . Because these whales can detect particle gradients in water, they can discern the salinity of the water, which could help them survive in their Arctic ice environment. They can also detect water particles that hint at the fish that make up their diet.
. . In the past, scientists have presented many theories to explain the tooth's purpose and function, although none of these have been accepted as definitive. One of the most common is that the tooth is used to display aggression between males, who joust with each other for social hierarchy. Another is that the tooth is a secondary sexual characteristic, like a peacock's feathers or a lion's mane.
. . The findings point to a new direction of scientific investigation. The tusk is also sensitive to touch, and narwhals are known for their "tusking" behavior, when males rub tusks with each other. Because of the tactile sensory ability of the tusk surface, the whales are likely experiencing a unique sensation.
. . Because of their physical structure, the tusks are both strong and flexible—an eight-foot-long tusk can yield one foot in any direction without breaking. For this reason, researchers are currently investigating narwhal tusks for practical insight into ways of improving restorative dental materials.
Dec 9, 05: Scientists working in Patagonia, South America, recently found remains of a 4-meter beast with 10-cm teeth. The creature, dubbed "Godzilla" by its discoverers, is a distant relative of today's crocodiles and lived about 135 million years ago.
. . Biologists have verified the existence of a true sea monster: the mysterious and elusive giant squid Architeuthis. Dead specimens periodically wash up on the world's beaches, most often in Newfoundland and New Zealand. The largest giant squid specimen, found in New Zealand, was estimated to be 20 meters long.
. . Some suggest that huge, unidentified masses that occasionally wash up on beaches throughout the world are sea monsters. These finds, often called "globsters", are obviously flesh, yet have decayed so badly that they lack bones or distinguishing features.
. . In 2004, Pierce and his colleagues examined all available globster specimens using electron microscopes, and applied biochemical, molecular, and DNA analysis --the samples matched exactly those of various species of great whales.
Dec 8, 05: Scientists have identified a major climate crisis that struck Africa about 70,000 years ago and which may have changed the course of human history.
. . The evidence comes from sediments drilled up from the beds of Lake Malawi and Tanganyika in East Africa, and from Lake Bosumtwi in Ghana. It shows equatorial Africa experienced a prolonged period of drought. It is possible, scientists say, this was the reason some of the first humans left Africa to populate the globe.
. . What makes the timing so fascinating is that it ties in with the "Eve hypothesis" of human evolution. Genetic studies suggest modern human society is descended from a group of around 10,000 individuals who lived in East Africa at the time of this crisis. Immediately after its end, human populations started to expand rapidly - and many of our ancestors began moving out of Africa and into the Middle East, Asia and Europe.
Dec 5, 05: Environmental researchers are preparing to capture what they call a new, mysterious species of carnivore on Borneo, the first such discovery on the wildlife-rich Indonesian island in over a century. Swiss-based environmental group WWF said its researchers photographed the strange animal, which looks like a cross between a cat and a fox, in the dense, central mountainous rainforests of Borneo.
. . The mammal, slightly larger than a cat with red fur and a long tail, very small ears and large hind legs, was photographed twice by a camera trap at night. It may live in trees during the day, coming down at night. Researchers hope to confirm the discovery by setting cage traps to catch a live specimen, but warn that Indonesian government plans to clear the rainforest to create the world's largest palm oil plantation may interfere with plans. The proposed plantation scheme, funded by the China Development Bank, is expected to cover an area of 1.8 million hectares, equivalent to about half the size of The Netherlands.
. . Environmental watchdogs have criticized the plan, arguing that the jungle soil in the area was infertile and that the elevation was unsuitable for palm oil.
. . Indonesia is losing at least 2.8 million hectares of its forests every year to illegal logging alone.
Dec 2, 05: Special neurons in the brainstem of rats focus exclusively on new, novel sounds and help them ignore predictable and ongoing noises, a new study finds. The same process likely occurs in humans and may affect our speech and even help us laugh.
. . The "novelty detector neurons", as researchers call them, quickly stop firing if a sound or sound pattern is repeated. They will briefly resume firing if some aspect of the sound changes. The neurons can detect changes in pitch, loudness or duration of a single sound and can also note shifts in the pattern of a complex series of sounds. Similar neurons seem to be present in all vertebrates and almost certainly exist in the human brain.
. . The novelty detector neurons seem able to store information about a pattern of sound, so they may also be involved in speech, which requires anticipating the end of a word and knowing where the next one begins.
. . "Speech fluency requires a predictive strategy", Covey explained. "Whatever we have just heard allows us to anticipate what will come next, and violations of our predictions are often surprising or humorous."
Dec 1, 05: A new analysis of Archaeopteryx, the earliest known birdlike animal, shows it had feet like dinosaurs —-a finding that adds weight to the belief that birds today are descendants of mighty ancient carnivores.
. . While not all scientists agree, many consider Archaeopteryx the first bird, since it had wings and was the first fossil found with feathers. It's the 10th known and one of the most complete.
. . Contrary to what had been thought, the new fossil shows that the first toe was not reversed in Archaeopteryx, as is the case on current birds. Lack of the reversed toe would hamper the animal's ability to perch like current birds. On the other hand, it's second toe could be extended, like those of theropod —-beast-footed-— dinosaurs, a group that included such well known examples as T. rex. Archaeopteryx was considerably smaller, however, close to the size of a magpie. The new example lived about 150 million years ago in what is now Bavaria.
. . The lack of a reversed toe doesn't mean an Archaeopteryx couldn't sit in a tree, but probably indicates that it was not a habitually tree-living animal.
. . Archaeopteryx was originally identified as the earliest fossil bird because of its feathers, Carrano said. Since then other dinosaurs with feathers have been found; if Archaeopteryx were discovered today it probably would be considered more dinosaur than bird, he said. But while the new discovery shows that Archaeopteryx was less birdlike than had been thought, he added, there were a lot of intermediate steps between dinosaurs and birds and this was one of them.
Nov 30, 05: A scientist in Scotland has discovered tracks made by a huge water scorpion 330 million years ago, the first of the species ever discovered and the only evidence showing it could survive outside of the water. It was a six-legged water scorpion measuring 1.2 meters long and a meter wide.
Nov 30, 05: The world's largest primate, a 3-meter-tall giant with inch-wide teeth, lived in southeast Asia for many centuries alongside human beings, according to a leading researcher.
. . Exploring remote caves isolated in a densely forested region of southern China, Jack Rink, a professor of geography and earth sciences at McMaster University in Ontario, found fossilized remains of the huge ape.
. . Using sophisticated fossil dating techniques, Rink determined that the primate, known to scientists as Gigantopithecus blackii, lived between 300,000 and a million years ago. Humans also existed in the area at that time.
. . The giant ape, who weighed as much as 1,200 pounds, was a plant eater, subsisting mainly on bamboo. This limited diet may have led to the ultimate extinction of Gigantopithecus, who had to compete for forest resources with humans and other animals.
. . Were humans responsible for the extinction of the primate? "We have absolutely no evidence of that", said Rink, who added that humans used bamboo only in limited amounts and may not have hunted the ape as a food source.
Nov 30, 05: Most mammals possess only one species of louse, but we have three (scalp, pubic and body lice). Biologists have long reasoned that they evolved from a common ancestor when we lost our body hair and evolved three unique patches of hair. And the recent DNA dating work of Mark Stoneking and his colleagues at the Max Planck Institute in Leipzig shows that our three lice separated from each other about 70,000 years ago, which dates our body nakedness to then.
. . About 70,000 years ago, the artistic instinct seems suddenly to have exploded in humans, and we lost our bodily hair to paint and decorate ourselves in uniquely creative ways. Why? For sex of course; but for a specially human type of sex — intelligent sex.
. . We find intelligence sexy because it translates into wealth and power. Repeated surveys have shown that the more intelligent a person is, the better is that person’s health, wealth and social standing. And because intelligence is linked to wit and creativity, the person who decorates their body in the most creative, charming or amusing way is signalling their intelligence and thus their attractiveness.
. . This month, Miriam Law Smith, of St Andrews University, showed that girls awash with estrogen are sexy. The higher the levels of a girl’s oestrogen, the larger are her eyes, the fuller her lips and the smaller her nose. Men like that sort of thing, and because estrogen also promotes fertility it is called an "honest" biological signal: it attracts men to women who are genuinely fertile. But Miriam Law Smith also found that women with low estrogen who used make-up shrewdly could fool men into finding them as attractive as their more fertile sisters. Art and IQ, in short, are mightier than the hormone.
Nov 20, 05: Among all the senses that organisms possess, vision is perhaps the most varied in all the animal kingdom. Millions of years of evolution have produced more than ten different animal vision systems, each perfectly tailored to suit the needs of its owner.
Nov 18, 05: In 2001, Alexei Erchak and colleagues at the Massachusetts Institute of Technology (MIT) demonstrated a method for building a more efficient LED. Most light emitted from standard LEDs cannot escape, resulting in what scientists call a low extraction efficiency of light.
. . The LED developed at MIT used a two-dimensional (2D) photonic crystal --a triangular lattice of holes etched into the LED's upper cladding layer-- to enhance the extraction of light. These high emission devices potentially offer a huge step up in performance over standard types.
. . Swallowtail butterflies in eastern and central Africa evolved an identical method for signalling to each other in the wild. They have dark wings with bright blue or blue-green patches. The wing scales on these swallowtails act as 2D photonic crystals, infused with pigment and structured in such a way that they produce intense fluorescence. Pigment on the butterflies' wings absorbs ultra-violet light which is then re-emitted, using fluorescence, as brilliant blue-green light.
. . Most of this light would be lost were it not for the pigment being located in a region of the wing which has evenly spaced micro-holes through it. This slab of hollow air cylinders in the wing scales is essentially mother nature's version of a 2D photonic crystal. Like its counterpart in a high emission LED, it prevents the fluorescent color from being trapped inside the structure and from being emitted sideways. The scales also have a type of mirror underneath them to upwardly reflect all the fluorescent light that gets emitted down towards it. Again, this is very similar to the Bragg reflectors in high emission LEDs.
Nov 17, 05: Tiny zircon crystals dug up from ancient Australian deposits appear to have been formed right after the birth of the planet --a finding that suggests that early on, Earth had a cool crust much like today's that could have harbored life, scientists said.
. . Most remnants of the very early crust, formed more than 4 billion years ago, are gone --recycled as part of the steady ongoing process known as plate tectonics. But the little zircon crystals survived, said Stephen Mojzsis. The key was a rare metal element known as hafnium, Mojzsis said. It is found with the zircons, and is capable of surviving recycling of the crust
. . They found their clues in sedimentary rocks from the Jack Hills in Western Australia, which date to almost 4.4 billion years ago. He said the finding now showed that within a few hundred million years of its creation, the planet had the three necessary elements for life --water, energy and organic compounds. It also might mean that life can occur easily --if the conditions can be right so soon after a planet forms, he said.
Nov 17, 05: Dallasaurus was a meter-long lizard that lived 92 million years ago in shallow seas and shores of what is now Texas. It is a missing link in the evolution of a group of creatures called mosasaurs, prehistoric animals that started out on land, but evolved in the seas and dominated the oceans at the same time dinosaurs ruled the land. They were the T. rex of the ocean.
.. "This is pretty close to the beginning of the mosasaur family tree." Dallasaurus retained complete limbs, hands and feet suitable for walking on land, whereas later mosasaurs evolved their limbs into flippers, the new study reports. Later mosasaurs grew up to 45 feet in length.
Nov 17, 05: A fossil reptile discovered in Brazil may be the oldest known creature that resembles a modern turtle. The 120-million-year-old find is linked to present-day representatives by its heavily webbed, paddle-shaped foot --an adaptation to life in the sea. Soft tissue has been preserved on the specimen, allowing scientists to confirm the webbing rather than infer it from the length of the foot bones.
Nov 17, 05: Fossilized dinosaur droppings found in central India show that giant dinosaurs known as titanosaurs ate grass, an international team of researchers reported. Few scientists had ever thought that dinosaurs grazed, because there was no evidence that grasses existed that long ago. They believed that the grinding teeth found in some dinosaur fossils were used for munching other plant matter, perhaps trees.
. . So when Caroline Stromberg of the Swedish Museum of Natural History received photographs of fossilized dinosaur droppings --she hardly expected to see pieces of grass in them. "It's certainly the first unambiguous evidence that grasses had originated by the late Cretaceous period and also that they had considerably diversified." That suggests that grasses had been around for a long time even back then.
. . Stromberg said some of the grass phytoliths look like those found in modern day rice. There are about 10,000 separate grass species.
Nov 17, 05: Scientists may have found a gene for fear --a gene that controls production of a protein in the region of the brain linked with fearful responses. Itcould lead to new treatments for mental disorders such as post-traumatic stress disorder and generalized anxiety.
. . The gene, known as stathmin or oncoprotein 18, is highly concentrated in the amygdala, a region of the brain associated with fear and anxiety. Learned fear develops after conditioning --as when a person is stung by a wasp and fears the insects afterward. These memories are formed in the amygdala.
. . "This is the first time it has been shown that the protein called stathmin --the product of the stathmin gene-- is linked to fear conditioning pathways."
. . Mice genetically engineered so they would not produce stathmin showed unusual behavior. Mice instinctively avoid open spaces, but the stathmin-free mice showed no fear and often explored more open areas than normal mice, the researchers found. So the gene may control both learned and innate fear, the researchers said. The mice might be useful for testing drugs and other treatments of anxiety disorders, they said.
Dr. van Schaik, a Dutch primatologist: Orangutans split off from the African lineage some 14 million years ago. Orangutans are the largest arboreal mammal and have no predators up in the trees so they live a very long time --up to 60 years in the wild-- and have the slowest life history of any nonhuman mammal.
. . A slow life history is key to growing a large brain. The other key to intelligence is sociability. Social tolerance is common to all great apes. It's rare in monkeys - except cebus monkeys; they're tool users, long-lived and socially very tolerant.
Nov 17, 05: After comparing the genetic code for snake and lizard venom, Bryan Fry at the University of Melbourne, Australia discovered that the two reptiles shared nine toxins. This supports the idea that snakes and venomous lizards evolved from a common venomous ancestor, and after connecting the DNA dots, Fry and his colleagues traced venom to a single origin 200 million years ago.
. . Bacteria has long been blamed as the aggravating agent in a Komodo dragon's nasty bite. Fry now suspects otherwise. "Bacteria couldn't work this quickly", he said. "The effects are totally inconsistent with bacteria." The effects –-a drop in blood pressure, loss of clotting ability, amplified pain, and loss of consciousness-– are more biologically consistent with venom.
. . Although lizard venom is just as strong as that of many snakes, it's not as much of a concern to humans. Snake bites send a much more concentrated dose of venom directly into a victim's bloodstream. A lizard's venom delivery system is less effective.
Nov 17, 05: More lizard families than previously believed are venomous, including several species that are popular pets, scientists said. Until now, pain and swelling from lizard bites assumed to be non-venomous were attributed to the bacteria that thrive on bits of meat left between their teeth from their scavenging diet. However, the symptoms are actually from the venom, a finding which could have implications for medical research.
. . A team of international scientists isolated crotamine --the classic venom of rattlesnakes whose bite can be fatal to humans-- in the eastern bearded dragon, a popular pet. However, the bearded dragon's delivery system is primitive and it is present in such small amounts it would not harm a human.
. . Fry said Indonesia's Komodo dragon --the world's largest lizard, weighing up to 160 kg-- is also venomous. It had previously been thought that only two families of reptiles were known to have venom systems --advanced snakes and Helodermatid lizards.
. . This study demonstrates there are venom toxins in two more lizard families: monitor lizards, such as the Komodo dragon, and iguania such as the bearded dragon and green iguana, but their toxin secreting glands are smaller than those of snakes. The study effectively doubles the number of potentially venomous reptile species to 4,600 from 2,300.
. . Snake toxins are already widely used in medicines to treat epilepsy, haemophilia and thrombosis. The new lizard venom toxins and their molecules present a huge unexplored resource for drug design and development.
Nov 10, 05: In the era when dinosaurs ruled the Jurassic earth, a 4-meter oceanic crocodile --Dakosaurus andiniensis-- with a short snout and a mouthful of deadly teeth hunted large creatures in the sea, scientists reported. The long narrow snout and small teeth of most crocs indicate feeding on small prey, Pol said, while Dakosaurus' large serrated teeth indicate a carnivore that would have hunted large prey. Instead of legs, Dakosaurus had four paddle-like limbs and a vertically oriented, fishlike tail. Dakosaurus would have regularly surfaced to gasp oxygen and then could dive into the ocean.
. . "This was a top predator that probably was [4 meters] long and swam around using its jagged teeth to bite and cut its prey, like dinosaurs and other predatory reptiles did", Pol said.
. . The world's relatively shallow seas between 230 million and 65 million years ago contained several large animals, such as the plesiosaur with a 6.5-meter neck and the giant ichthyosaurs that could be 25-meters long.
Nov 10, 05: A study of DNA from ancient farmers in Europe shows sharp differences from that of modern Europeans —-results that are likely to add fuel to the debate over European origins. Researchers led by Wolfgang Haak of Johannes Gutenberg University, argue that their finding supports the belief that modern residents of central Europe descended from Stone Age hunter-gatherers who were present 40,000 years ago, and not the early farmers who arrived thousands of years later.
. . Haak's team used DNA from 24 skeletons of farmers from about 7,500 years ago, collected in Germany, Austria and Hungary. 25% — belonged to the "N1a" human lineage. The N1a marker is extremely rare in modern Europeans, appearing in just 0.2%. "Our paper suggests that there is a good possibility that the contribution of early farmers could be close to zero."
. . But. The study didn't compare the DNA of the ancient farmers with that of the ancient hunter-gatherers, adding that there are plenty of hunter-gatherer burials in German cave sites that could have been sampled for comparison. Without that comparison, it's hard to say that the difference between modern DNA and that of the ancient farmers means current people are descended from the ancient hunter-gatherers.
. . "I see nothing in the data that would necessarily carry the exclusion of, for instance, the opposite hypothesis ... that (the N1a marker) represents the incorporation of hunter-gatherer females in the farming communities that are coming into Europe about 7,500 years ago, that incorporation being in such small numbers that, eventually, it all but disappeared."
Nov 9, 05: The popular view that islands were dead-ends of evolution may have to be rewritten after new research found exactly the opposite. Far from species hopping steadily down an island chain from a continent and coming to a dead stop, the research using new techniques shows the process can actually go into reverse and spread back to the continents.
. . "The original source was continental but if you look at island lineages and analyze all the unique forms at once, as we have, you find that the Pacific is an engine of diversity ... that can contribute to continental diversity." "Islands aren't just little landforms worth saving as icons of evolutionary quirkiness ... They are important in a broader sense and may contribute significantly to future diversity of life on earth", Filardi said.
Nov 8, 05: The breakup of giant icebergs may have forced minor evolutionary changes in penguins over the past 6,000 years, a new study suggests.
. . The Antarctic iceberg chunks, which break off the continent now and then, are thought to have blocked the swim paths of Adelie penguins returning home to their colonies. Some of the penguins were forced to become immigrants in other colonies, where they established new homes and interbred with the locals.
. . As a result, genetic changes that might otherwise have remained isolated became widespread among the different colonies. The result is what scientist call microevolution. Microevolution involves small-scale genetic changes in a species over time. The classic example is a color change undergone by British pepper moths in response to changing levels of air pollution. The acquisition of antibiotic resistance by bacteria and the trend towards tusk-less elephants in Africa are also examples of microevolution at work.
. . Adelie penguins may be the ideal candidates for such research. The penguins often live, breed and die in the same colonies where they were born and where their ancestors before them lived. And the remains of ancestor birds are well preserved in distinct layers of the frigid terrain, making fossil dating relatively easy. For the study, the researchers extracted DNA from the bones of 6,000-year-old penguins and compared them to the DNA of their modern descendents.
. . The researchers think icebergs may have been a constant evolutionary pressure for the penguins and estimate that there have been about 200 such events within the past 10,000 years.
Nov. 4, 2005 — The primordial pond scum that gave rise to the chemical ingredients of life may have actually been hot, deep-sea volcanic clay, say Arizona researchers who have recreated high-temperature and high-pressure conditions of that environment in a laboratory.
. . The researchers discovered that methanol —-made naturally when volcanic carbon dioxide combines with volcanic hydrogen gas-— hides out from the intense heat of volcanic vents between the layers of certain common clays. The clays themselves are just degraded lava rock. Once safely inside clay, methanol reacts with a clay mineral called montmorillonite to create far more complex organic molecules with up to 20 carbons. "People have no problem with the idea that organic reactions go on in clays", said Lynda Williams of Arizona State University. What they haven't seen until now, however, is the creation of complex organic compounds from simple, volcano-borne chemicals.
. . The laboratory work shows that the expandable, many-layered montmorillonite both provides protection from the 475° Fahrenheit (300° Celsius) heat and many mineral surfaces that serve as a sort of factory floor for building complex organics. As time goes on, the clay contracts and expels the complex molecules, which have a good chance of surviving if they drift to nearby cooler waters.
. . After all, if clays can make organics, what's stopping them from making crude oil?
Nov 7, 05: A gigantic ape standing 3 meters tall and weighing up to 540 kg (1,200 pounds) lived alongside humans for over a million years, according to a new study. Fortunately for the early humans, the huge primate's diet consisted mainly of bamboo.
. . Scientists have known about Gigantopithecus blackii since the accidental discovery of some of its teeth on sale in a Hong Kong pharmacy about 80 years ago.
. . Jack Rink, a geochronologist, has used a high-precision absolute-dating method to determine that this ape –-the largest primate ever-– roamed Southeast Asia for nearly a million years before the species died out 100,000 years ago during the Pleistocene period. By this time, humans had existed for a million years.
. . Researchers do not have a full skeleton for Gigantopithecus. But they can fill in the gaps and estimate its size and shape by comparing it to other primates – those that came before it, coexisted with it, and also modern apes. Currently, scientists are debating over how Gigantopithecus got around – was it bipedal or did it use its arms to help it walk, like modern chimpanzees and orangutans? The only way to answer this is to collect more bones.
Nov 3, 05: A Vatican cardinal said today the faithful should listen to what secular modern science has to offer, warning that religion risks turning into "fundamentalism" if it ignores scientific reason.
. . Cardinal Paul Poupard, who heads the Pontifical Council for Culture, made the comments at a news conference on a Vatican project to help end the "mutual prejudice" between religion and science that has long bedeviled the Roman Catholic Church and is part of the evolution debate in the United States.
. . The Vatican project was inspired by Pope John Paul II's 1992 declaration that the church's 17th-century denunciation of Galileo was an error resulting from "tragic mutual incomprehension." Galileo was condemned for supporting Nicolaus Copernicus' discovery that the Earth revolved around the sun; church teaching at the time placed Earth at the center of the universe.
. . "We know where scientific reason can end up by itself: the atomic bomb and the possibility of cloning human beings are fruit of a reason that wants to free itself from every ethical or religious link", he said. "But we also know the dangers of a religion that severs its links with reason and becomes prey to fundamentalism", he said.
Nov 3, 05: This was no one-night stand! Scientists in India say they have discovered two fossils fused together in sexual union for 65 million years. But voyeurs will need a microscope to view the eternal lovers. The fossils are tiny swarm cells, a stage in the development of the fungus myxomycetes, also known as slime molds.
Nov 2, 05: The evolutionary process that Charles Darwin discovered almost 150 years ago, responsible for transforming dinosaurs into birds and allowing the walking ancestors of whales to take to the seas, is still quietly at work in humans today.
. . Darwin's natural selection is the process by which nature rewards those individuals better adapted to their environments with survival and reproductive success. It works at the level of genes, sections of DNA that encode for proteins serve as the software of life.
. . In one of the most detailed human DNA studies ever conducted, researchers analyzed nearly 12,000 genes from 39 people and a chimpanzee, our closest living relative. The findings suggest that about 9% of the human genes examined are undergoing rapid evolution.
. . A separate study announced last month indicated the human brain is still evolving, too.
. . Bustamante's team found that the genes most affected were those involved in immunity, sperm and egg production and sensory perception. A comparison between human and chimpanzee genomes found that these genes have undergone more changes in humans than in chimps, despite the fact that the two species shared a common ancestor some 5 million years ago.
. . The genes for a group of proteins important for switching other genes on and off, known as "transcription factors", were found to vary significantly in humans and chimps. One reason for this could be that turning a gene on or off is easier than changing the gene itself.
. . "We believe that if you want to evolve a system, it's usually easier to tweak when the protein gets turns on or the total amount of a protein as opposed to the amino acid itself."
. . Another 13% of the genes examined in the study showed evidence for negative selection, whereby harmful mutations are weeded out of the population. These included some genes implicated in hereditary diseases, such as muscular dystrophy and Usher syndrome. The latter is the most common cause of congenital blindness and deafness in developed countries.
. . Medical geneticists are interested in finding genes sensitive to negative selection because they might one day be useful for predicting an individual's likelihood of developing a disease if the types of mutation to a gene and the environmental conditions are known. Being able to determine which classes of genes are particularly vulnerable to negative selections is a first step.
. . Bustamante's work provides examples of its pace and extent and offers the promise of medical advances down the road.
Nov 2, 05: Songbirds may be the Sinatras of the animal world, but male mice can carry a tune too, say Washington University researchers who were surprised by what they heard.
. . Scientists have known for decades that male lab mice produce high-frequency sounds —-undetectable by human ears-— when they pick up the scent of a female mouse. This high-pitched babble is presumably for courtship, although scientists are not certain. But it turns out those sounds are more complex and interesting than previously thought.
. . "It soon became ... apparent that these vocalizations were not random twitterings, but songs", said researcher Timothy Holy. "There was a pattern to them. They sounded a lot like bird songs." To make their point, the researchers provided audio recordings of the sounds, which have been modified for human ears --reconstructing them four octaves lower.
. . Bird song, how it is perceived and learned, is used to understand how the human brain works. But some questions might be posed better with mice, for experimental convenience, he said. If it is true that the male mice are producing songs, it raises questions about how their sounds develop and whether mice —-like birds-— are able to learn new sounds. The only mammals known to learn new sounds are whales and porpoises, and "they're not exactly ideal for study."
. . The mice sounds met two key criteria for song — distinct syllables and recurring themes, "like the melodic hook in a catchy tune." He said their finding is not just perception, but a "very careful quantitative analysis of sounds." Holy said adult bird songs are much more practiced, predictable and refined than those of mice, but even birds don't start out as great singers. They learn.
Oct 27, 05: Bird-like lungs could have helped the biggest dinosaurs reach their astonishing size, say scientists. They said sauropods, which reached 40 meters and weighed 100 tons (10 times as much as the largest elephants) sucked in air more efficiently than mammals today. In mammals, a diaphragm pumps air through the lungs.
. . Birds have up to nine extra air sacs to supplement their lungs. And birds' "lung" tissues are only half as thick as those of mammals. It adds up to around 80% greater efficiency.
Oct 27, 05: Chimpanzees share many traits with humans but altruism, it seems, is not one of them, scientists said today. When given the opportunity to help themselves and other chimps they often choose the selfish option.
. . They devised an experiment in which chimps on one side of a window could pull a handle to provide a tray of food for themselves or to also give the same reward to a monkey in another room on the opposite side of the window. Both groups of unrelated chimpanzees behaved in a similar way. They decided to reward themselves but not others.
Oct 21, 05: Tiny fleas that survive on fungus found under a blanket of snow contain a unique antifreeze that could have implications for farming or transplant surgery, Canadian researchers said. Their findings could help protect plants or animals from frost, or allow donated transplant organs to be stored and transported at lower temperatures.
. . "Theoretically, with this antifreeze protein we might be able to store an organ at minus 6 degrees (usta be 21 degrees F). Hopefully, it would be able to last longer so that you would have longer to do tissue matching to get the organ to the patient and just increase the shelf life of organs."
. . Another possible application could be in crops, allowing fruit trees to survive a cold snap. "If you were able to genetically modify any crop that was susceptible to frost you may be able to generate a crop that's not so sensitive."
. . The researchers found that the antifreeze proteins in the snow fleas were different from those in beetles and moths, prompting them to conclude that these antifreeze proteins evolved independently in the snow fleas.
Oct 18, 05: A new species of flying reptile that died out with the dinosaurs 65 million years ago has been named for its fang-like teeth, British scientists said. Paleobiologists at the University of Portsmouth in southern England dubbed the remains of the pterosaur found on a beach on the Isle of Wight three years ago.
. . They gave it the name Caulkicephalus trimicrodon. Caulkhead is the informal name for natives of the Isle of Wight, off the southern coast of England, and trimicrodon means [see it?] three small teeth. "It has massive fang-like front teeth, behind which are three small teeth. Behind those are bigger teeth and then rows of smaller teeth."
Oct 18, 05: Tracks of a previously unknown swimming dinosaur have been found along the shores of an ancient sea in Wyoming, scientists announced today. The tracks reveal an event 165 million years ago when a 2meter-tall, two-legged dinosaur waded into the inland sea and gradually lost touch with the ground.
. . "It was about the size of an ostrich, and it was a meat-eater", said Debra Mickelson, a University of Colorado at Boulder graduate student. "The tracks suggest it waded along the shoreline and swam offshore, perhaps to feed on fish or carrion. The tracks show how it became more buoyant as it waded into deeper water --the full footprints gradually become half-footprints and then only claw marks."
Oct 17, 05: The Velociraptor dinosaur made famous by the Hollywood movie Jurassic Park may not have been quite the super-efficient killer we all thought. Like other dinos in its family, it had a distinctive sickle-shaped claw on the second toe which many have assumed was employed to disembowel victims. But tests on a mechanical arm suggest this fearsome-looking appendage was probably used just to hang on to prey.
. . The Kevlar and carbon-fiber-coated aluminum claw was thrust into the flesh from pig and crocodile carcasses. Instead of producing the expected slashing wounds, the robotic impacts created only small, rounded punctures. What's more, the way the skin tissue bunched under the impacts prevented the claw from withdrawing easily.
Oct 17, 05: A sea creature killed just before it could defecate has given new insight into the feeding habits of plesiosaurs. The fossilized contents of its lower intestine show the long-necked marine reptile had a fondness for clams and snails --food items from the sea floor. (benthic = bottom-dwelling)
. . The team actually examined the fossilized remains of two elasmosaurids, the most extreme form of plesiosaur that had necks longer than their bodies and tails combined.
. . The plesiosaurs would have been 5-6m in length and about a tonne in weight. One of the specimens contained a bromalite, a fossilised mass of food waste. "The indigestible parts of the prey were compacted together, just prior to being expelled, and the result was a solid lump of digested food composed entirely of broken shells from bottom living animals." Large polished pebbles were found within the stomach region. Both specimens had them. Explained Dr Wroe: "The role of these gastroliths, or stomach stones, has been an area of contention for many years.
. . "In marine animals, there's certainly a theoretical advantage with respect to buoyancy control or ballast; but with these plesisaours, these stones would have been very useful for crushing up clam shells and snail shells."
Oct 17, 05: New analysis of the winged Microraptor gui suggests that the first feathered dinos relied on a biplane-like wing configuration to swoop from tree to tree. The result may settle a century-old controversy over how the first feathered creatures achieved flight.
. . The chicken-sized Microraptor, which lived in the early Cretaceous period some 140 million years ago, had long flight feathers on its forelimbs and feet, the first time such an arrangement has been discovered. Flight feathers have a narrow leading edge and thick trailing edge, which helps create upward lift and streamlines the body in flight.
. . When Chinese paleontologists discovered and reconstructed the Microraptor, they assumed that it flapped its four wings in tandem like a dragonfly. But when Chatterjee and his colleagues –-who had previously used computer models to redefine the flight abilities of pterosaurs and another feathered dino, Archaeopteryx-– inspected Microraptor’s skeleton, they quickly determined this wasn’t the case.
. . "The problem we faced is that the legs of Microraptor, like on any other dinosaur, could not be splayed sideways", Chatterjee said. Since they couldn’t extend their hind wing directly behind the front wing, Macerators probably held their feet lower than their arms, a more aerodynamically stable configuration, Chatterjee says. From the side, they would have looked like a staggered biplane.
. . "It mainly glided, but probably had to flap a little during takeoff and landing, or in case of an emergency." Microraptors were probably clumsy on the ground. "Since they have these six-inch long feathers on their feet, they would have trouble running and would be vulnerable on the ground."
. . This new discovery and several others in China, support the "trees-down" theory where gravity was the main source of flying energy. The Chinese fossils, which are well preserved, show several transitional stages from wingless tree-dwellers, to winged gliders, to active flyers with large feathers designed to provide greater lift and thrust.
Oct 12, 05: The discovery of a bird-like dinosaur in South America has paleontologists rethinking when, where and how one group of raptors evolved. The rooster-sized dinosaur is called Buitreraptor (bwee-tree-rap-tor) gonzalezorum. It has a long head and long tail and wing-like forelimbs. Its serrated teeth, like steak knives, suggest it was a carnivore.
. . Buitreraptor is related to Velociraptor, the presumably cunning killer made famous by Hollywood. Both belong to a class of birdlike dinosaurs that ran swiftly on two legs and are called dromosaurs (runner-lizard].
. . The new find suggests such raptors go back much further in time that previously thought. Until recently, dromaeosaurs had been found only in Asia and North America and only in the Cretaceous period, which ran from 145 million to 65 million years ago. Evidence that they existed in the Southern Hemisphere has been mounting.
. . Today's announcement of a well preserved fossil represents the first definitive evidence that dromaeosaurs roamed South America.
. . * Either dromaeosaurs existed when Pangea was intact;
. . * or the newfound Buitreraptor and its northern look-alikes evolved separately yet with remarkably similar results.
Odds being against such striking parallel evolution, paleontologists speculate that dromaeosaurs likely originated more than 180 million years ago, before Pangaea broke apart. The newly discovered fossil also shows that the creatures developed slightly different characteristics after they split up.
. . Buitreraptor is an odd duck among dinosaurs. Its peculiarly long snout may have evolved to hunt snakes, mammals, and lizards that burrowed into the ground. Fossils of such critters found near Buitreraptor suggest that scenario.
. . The large, hollow wishbone of the dinosaur, along with its wing-like forelimbs and bird-like pelvis, add more evidence to the theory that birds evolved from dinosaurs, the scientists said.
. . An analysis of Buitreraptor also reveals it to be very similar to Rhonavis, which had been thought to be a primitive bird. The researchers now believe the two constitute a separate branch of the dromaeosaur family tree.
Oct 12, 05: A special type of protein enables insects to chirp, fly, and hop. Now, scientists have produced this same protein in the lab and say it could one day be used to repair human arteries.
. . Since it is structurally similar to elastin, the molecule that allows blood vessels to expand and contract, scientists think they may be able to use the manufactured resilin to repair stretched out, damaged blood vessels.
. . The protein, called resilin, is like rubber. It can be squished up, storing energy for a quick release, and it remains extremely functional over an insect's lifetime. Flies take advantage of the material's durability to flap their wings more than 720,000 times an hour. Froghoppers and fleas achieve a jump acceleration of more than 400 times gravity in just one millisecond thanks to the quick release of energy from a tendon full of resilin.
. . While most insects use it for getting around, others, such as cicadas, moths, and some crustaceans, use it like a drum to make noise. And if incorporated into an insect's outer shell, resilin provides elasticity to an otherwise stiff structure. This is how termite queens manage to haul around a load of eggs and how ticks store their sperm.
. . Scientists at the Commonwealth Science and Industrial Research Organization in Australia took a copy of the resilin gene from a commonly used research fly, Drosophila melanogaster, and inserted it into the genome of E. coli bacteria. E. coli is the bacterial equivalent of a protein factory, and once the researchers had coaxed it into producing the protein, they exposed it to light to create the rubber-like molecule.
. . In the science world, resilience is the measure of a material's ability to recover after deformity under applied stress. Resilin is one of the most resilient materials around –-it can be stretched three times its original length without breaking.
Oct 2, 05: Vienna Cardinal Christoph Schoenborn said he could believe both in divine creation and in evolution because one was a question of religion and the other of science, two realms that complimented rather than contradicted each other. "Without a doubt, Darwin pulled off quite a feat with his main work and it remains one of the very great works of intellectual history."
Oct 2, 05: Wild gorillas use tools every day, but scientists never had lasting proof until two tool-using apes were recently caught on film. While all other great apes –-such as chimpanzees and orangutans-– have been observed using tools in the wild, these photographs provide the first evidence of tool-savvy wild gorillas.
. . One gorilla used a long stick to test the depth of a pool of water before wading into it. Another used a stick to help search for food and then as a bridge over a muddy puddle.
. . Prior to this discovery, most observed tool usage by wild great apes related directly to obtaining food, either by cracking nuts with rocks or using twigs to eat termites. This research shows that other factors, such as habitat, can inspire tool use.
Sept 22, 05: According to local legend, peculiar clearings in the Amazon rainforest made up of a single tree species were created by an evil spirit. Now, researchers have identified a more likely culprit for these so-called devil's gardens. It's a chemical-wielding ant that looks to be nature's own little gardener.
. . The ant, Myrmelachista schumanni, makes its home in the hollow, swollen stems of Duroia hirsuta, the tree that dominates devil's gardens. D. hirsuta trees only grow to about 4 meters, much shorter than the rest of the rainforest's canopy. "Someone walking around the jungle who steps into a devil's garden would immediately notice the difference between the garden and the surrounding vegetation", study author Megan Frederickson of Stanford University told LiveScience. "It looks a lot like an orchard –-as if someone had come along and planted the trees."
. . Scientists previously thought that the D. hirsuta bullied out other plants in the area to create the devil's gardens. Now evidence suggests that it's the ants doing the bullying, by using their own herbicide to kill trees and plants that don't serve them.
. . To determine if this is indeed the case, Frederickson and her colleagues planted saplings of a common Amazonian cedar tree –-Cedrela odorata-– inside and outside the devil's gardens. "We found that the M. schumanni workers promptly attacked the saplings in devil's gardens."
. . The ants injected poison into the saplings leaves, which began to die within 24 hours. Most of the leaves fell off over the course of the next five days. Chemical analysis showed that the ants use formic acid to kill intrusive plants. While formic acid production isn't uncommon in ants, this research provides the first known instance of ants using it as an herbicide.
. . Each devil's garden is the home to one giant ant colony –-as many as three million workers and 15,000 queens. The colony's immense size, and ridiculously high number of queens, contributes to the longevity of the colony, which can span more than 800 years.
Sept 21, 05: Scientists in Israel have just developed a new technique to retrieve better quality, less contaminated DNA from very old remains, including human bones. It could aid the study of the evolution and migration of early modern humans, as well as extinct populations such as our close relatives, the Neandertals. "Neandertals are three times as different from us as we all are from each other", says Professor Stringer.
. . The DNA most widely accepted as oldest yet isolated comes from 400,000-year-old plants found in ice in Siberia.
. . "Crystal aggregates", small mineral pockets formed during fossilization, can preserve DNA better than the rest of the bone. They compared DNA extracted from these crystal aggregates with genetic material taken from untreated, whole-bone powder. The samples were taken from eight different modern and fossil bones.
They found better preserved, less contaminated DNA could be recovered from the isolated crystals.
. . There's about 1,000 times more mitochondrial DNA than nuclear DNA in our cells.
Sept 21, 05: Scientists have examined the genes of "whale lice" to track whale evolution. The small parasitic crustaceans were taken off right whales, which have been driven to the brink of extinction in some waters by commercial hunting.
. . Two of the three whale species are on the brink of extinction. Only about 200 survive in the North Pacific, 350 in the North Atlantic, while the Southern Hemisphere population numbers around 8,000 to 10,000.
. . The new research studied the genes of so-called whale lice --not lice as we would normally think of them, but harmless, small crustacean parasites that live on the surface of the marine mammals. The genetics of the lice reveal their hosts split into three species 5-6 million years ago, and these were all equally abundant before whaling began.
. . The idea was to understand the evolution of these giants by getting at the genetics of creatures that have spent most time with them. The whale lice --properly called cyamids-- look like miniature crabs and are between 0.5 - 1.5cm in length. About 7,500 live on the surface of a single whale, feeding on sloughed skin.
. . As they spend their entire lives on the whales, both species share a common history. And in certain respects, the parasite's genes actually tell scientists more about the whale's history than its own genes. The study gives an estimate of when a single species of right whale diverged into three different species.
. . "The genetics of whale lice show conclusively that the three species of right whales have been isolated in the North Pacific, North Atlantic and Southern Hemisphere for about 5-6 million years."
. . The lice were recovered from beached whales. Isolation by physical barriers allows separate species to form. Warm currents also kept right whales from moving between southern and northern oceans. "Right whales have such thick blubber they can't cross the equator", says Dr Rowntree. "The waters are too warm. They can't shed heat."
. . However, the new study also showed that at least one southern right whale did manage to cross the equator 1-2 million years ago.
Sept 16, 05: Young children can perform certain kinds of math operations before ever receiving any kind formal math training, a new study reports. The finding suggests children have an inborn intuition about math that could be used to make learning the real thing in school less painful.
. . Ask a 5-year old child whether the sum of 13 and 17 is greater or less than 50 and chances are you'll just get a funny look. But the same problem could be presented another way, as a visual problem, and this is what the researchers did.
. . In one experiment, the children saw 13 blue dots on a computer screen; those were covered, and then they saw 17 blue dots and were forced to keep the running tally in their heads. Then they were shown 50 red dots and asked whether there were more blue dots or red dots. Presented this way, the children answered correctly about two-thirds of the time that there were more red dots than blue dots.
. . In another experiment, the children were asked to compare the number of blue dots on the screen with audible beeps that represented red dots. Again they were generally able to determine which was more, suggesting they have an abstract notion of numbers that spans multiple sensory modalities, just like adults.
Sept 14, 05: Brain size matters if you are a bird, according to a new study. Birds with bigger brains adapted better to the environment and therefore did better, according to scientists from The Royal Society for the Protection of Birds. The study found that populations of birds like gray partridges and corn buntings --all with relatively small brains relative to their size-- had dropped sharply.
. . At the same time, those with relatively larger brain sizes like blue tits and magpies had fared far better. "Large brains may help birds solve problems and adapt their behavior as their environments change."
Sept 8, 05: The giant reptiles that flew above the earth until about 65 million years ago could have grown to twice the size originally thought with wingspans of at least 18 meters, a paleontologist said today. It was roughly five times bigger than an albatross, which ranks among the birds with the largest wingspans in the modern world.
. . Dr David Martill of the University of Portsmouth in southern England, said his research on pterosaur wings appeared to solve the problem of how such enormous creatures managed to take to the skies and stay there.
. . Recent fossil finds in Mexico and Israel added weight to the theory that this prehistoric, flying reptile, which became extinct at the same time as the dinosaurs, could have been much bigger than many had realized. Martill said fellow academic and collaborator Dr Eberhard "Dino" Frey of the Natural History museum in Karlsruhe, Germany, had recently found distinctive fossilized footprints in Mexico pointing to a creature with a wingspan "in excess of 18 meters."
. . Despite its size, Martill believes his studies of the bone structure and tissue of a pterosaur wing show it could have flown "really rather elegantly. The wing membrane is really very, very thin", he said, adding that the samples were about half a millimeter thick. "One of the other things we found out that was excitingly new was a very different shoulder joint."
. . The elaborate structure of the wing, more like that of a bat than a bird, combined with hollow bones and a body not much bigger than a human torso would have kept weight to a minimum. "One imagines that the take off problems were less ... particularly if you add the fact that they were very, very lightly constructed to this enormous wing membrane area."
. . Martill said he had established that the wing was locked into the bottom of the body rather than the top, providing a greater surface area to benefit from the thermal air currents that give lift during flight.
. . More cumbersome would have been the neck, stretching to three meters in length and attached to a skull that could have added an additional two meters. Although not very aerodynamic, it might have allowed the pterosaur to pick up prey from the sea without flying dangerously close, Martill suggested.
. . As for why they grew so big, it could have been a function of age: "One of the reasons might be that they just kept on growing", rather than reaching an adult size when growth stops.
Sept 8, 05: The human brain may still be evolving. So suggests new research that tracked changes in two genes thought to help regulate brain growth, changes that appeared well after the rise of modern humans 200,000 years ago.
. . That the defining feature of humans —-our large brains-— continued to evolve as recently as 5,800 years ago, and may be doing so today, promises to surprise the average person, if not biologists. "There's a sense we as humans have kind of peaked", agreed Greg Wray, director of Duke University's Center for Evolutionary Genomics. "A different way to look at is it's almost impossible for evolution not to happen."
. . It's far from clear what effect the genetic changes had or if they arose when Lahn's "molecular clock" suggests —-at roughly the same time period as some cultural achievements, including written language and the development of cities.
. . Lahn and colleagues examined two genes, named microcephalin and ASPM, that are connected to brain size. If those genes don't work, babies are born with severely small brains, called microcephaly.
. . Using DNA samples from ethnically diverse populations, they identified a collection of variations in each gene that occurred with unusually high frequency. In fact, the variations were so common they couldn't be accidental mutations but instead were probably due to natural selection, where genetic changes that are favorable to a species quickly gain a foothold and begin to spread, the researchers report.
. . Lahn offers an analogy: Medieval monks would copy manuscripts and each copy would inevitably contain errors —-accidental mutations. Years later, a ruler declares one of those copies the definitive manuscript, and a rush is on to make many copies of that version —-so whatever changes from the original are in this presumed important copy become widely disseminated.
. . Scientists attempt to date genetic changes by tracing back to such spread, using a statistical model that assumes genes have a certain mutation rate over time. For the microcephalin gene, the variation arose about 37,000 years ago, about the time period when art, music and tool-making were emerging, Lahn said. For ASPM, the variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said.
. . "The genetic evolution of humans in the very recent past might in some ways be linked to the cultural evolution", he said.
. . Other scientists urge great caution in interpreting the research. That the genetic changes have anything to do with brain size or intelligence "is totally unproven and potentially dangerous territory to get into with such sketchy data", stressed Dr. Francis Collins, director of the National Human Genome Research Institute. Aside from not knowing what the gene variants actually do, no one knows how precise the model Lahn used to date them is, Collins added.
. . Lahn's own calculations acknowledge that the microcephalin variant could have arisen anywhere from 14,000 to 60,000 years ago, and that the uncertainty about the ASPM variant ranged from 500 to 14,000 years ago.
Sept 5, 05: Eclipse, the stallion described as the greatest racehorse of all time, is to have his DNA studied by scientists. The team, from the Royal Veterinary College and Cambridge University, hope to get an insight into what made him such a great champion. Eclipse was never beaten when he ran in 1769 and 1770 and was retired largely because of the lack of competition.
. . But getting at the DNA will be a tricky business, because the molecule degrades quickly over time. Scientists at Cambridge's McDonald Institute will have to use sensitive techniques recently developed to retrieve DNA from ancient human remains.
. . The research will give insights into the origins of the world's thoroughbred racing stock. Research conducted at Trinity College Dublin has already shown that today's racehorses can trace their line to a very small group of animals imported from the Near East and North Africa in the early 1700s. "The effective number of founders is only about 28."
Sept 2, 05: Ocean researchers have returned to the Gulf of Mexico where they are getting a revealing new look at the deep sea. National Oceanic and Atmospheric Administration Research Vessel Seward Johnson are using a camera that operates with dim red light to study life on the sea floor.
. . They have found a variety of deep-dwelling shellfish that produce their own light, animals with surprising ability to see ultraviolet light and a previously unknown type of squid, six feet long, that attacked their camera. Some have the ability to see ultraviolet light, Frank said. They are trying to determine why. "As far as we know there is no ultraviolet light down there", she said. One theory is that it helps them see creatures that produce their own biological fluorescence. "The discovery that one of deep-sea crabs has ultraviolet vision is thrilling", said Widder. "The question is what the heck are they doing with it."
. . Some of the creatures also seem able to see polarized light, perhaps to help them detect camouflaged predators or prey.
. . As many as 80% of animals in the deep sea produce some light, she said.
Sept 2, 05: Peruvian explorers have discovered the fossilized remains of a giant, 14-meter-long crocodile deep in the Amazon jungle, lending credence to a theory that the world's largest rain forest was once a huge inland sea, a scientist said. Once weighing 9 tons and with a 1.3-meter-long head, the crocodile is only the second fossil discovery of its kind in three decades. Other reptiles and giant armadillos were also found nearby.
. . Scientists believe the collision of the South American and the Nazca plates 15 million years ago formed the Andes mountains, blocking the Amazon river which flowed westward and causing the area to become a vast inland sea.
Sept 1, 05: A reconstruction of the skeleton of the first four-legged land animal suggests that it didn't move too nimbly on land --it either shuffled along or crept like an inchworm.
. . 360 million years ago, Ichthyostega crawled out of the water onto land. Although it was an amphibian, many of its skeletal features were fish-like. But it also had sturdy shoulders and hips, capable of supporting the body's weight on land. The specialized shoulders and hips also allowed it to move its limbs out of water, making them useful for getting around on land. But Ichthyostega got around unlike any animal seen today.
. . "On the one hand, it could have 'walked' with the body held rigid and the limbs moving in alternating diagonal sequence --front left and hind right, front right and hind left", Ahlberg told LiveScience. "The forelimbs were robust with bent elbows and could probably lift the front part of the body off the ground, but the hind limbs were more flipper-like so the pelvic region probably dragged on the ground."
. . Or the animal may have moved more like an inchworm by pulling its hips and back legs up towards its shoulders and then extending its back to move its front legs forward. This would have allowed Ichthyostega to push itself along with reasonable efficiency.
. . Although Ichthyostega could move around on land, it probably spent plenty of time in the water. In water, its broad tail and flipper-like limbs would have allowed it to swim around.
Sept 1, 05: Did Neandertals and the first ancestors of modern man ever meet? The argument has raged among archaeologists and paleontologists for decades. Now a group of scientists claim to have proof --based on radiocarbon dating of artefact finds in France-- that the two distinct groups did indeed share the same space at the same time some 38,000 years ago.
. . "These data strongly support the chronological coexistence --and therefore potential demographic and cultural interactions-- between the last Neandertal and the earliest anatomically and behaviourally modern human populations in western Europe", they wrote.
. . Some scientists have argued that Neandertals and the first ancestors of modern man existed at the same time --at least for a while-- but in different places, while others have argued that Neandertals died out before modern man came along. Others still have suggested that they not only met but may even have interbred. The arguments have ebbed and flowed for generations --fueled from time to time by new artefact finds, mainly from Kenya's Rift Valley.
. . But this team of scientists believe they may have settled the dispute with analysis of tools discovered at different depths in the cave of the Grotte des Fees at Chatelperron in central France.
. . In the cave a layer of tools from the later so-called Aurignacian culture --named after Aurignac near Spain where they were first discovered-- were found sandwiched between two layers of tools attributed to earlier Neandertals. Aurignacian tools are more sophisticated and deemed to have been made by the first modern humans.
. . The scientists, led by Paul Mellars from Cambridge University, said the layers suggested that not only had the two groups been around at the same time but that they must have shared the same space --at least for a while. Radiocarbon dating of some of the bone fragments from the different layers confirmed the observational conclusions.
. . The scientists suggested that encroaching cold may have made the Aurignacians move toward the warmer coast from central Europe and at the same time encouraged the Neandertals to move even further south where it would have been even warmer. When the weather warmed again in later generations, the population flow was reversed --suggesting that the ancestors of modern man may have been better equipped to deal with colder climates than the last groups of Neandertals, they said.
Sept 1, 05: Scientists have deciphered the DNA of the chimpanzee, the closest living relative of humankind, and made comprehensive comparisons with the human genetic blueprint. There are no firm answers yet about how humans picked up key traits such as walking upright and developing complex language. But the work has produced a long list of DNA differences with the chimp and some hints about which ones might be crucial.
. . An international team of researchers identified virtually all the roughly 3 billion building blocks of chimp DNA. "It's a huge deal", said Dr. Francis Collins, director of the National Human Genome Research Institute, which provided some support for the project. "We now have the instruction book of our closest relative." He said the work will help scientists analyze human DNA for roots of disease.
. . Humans and chimps have evolved separately since splitting from a common ancestor about 6 million years ago, and their DNA remains highly similar --about 96% to almost 99% identical, depending on how the comparison is made. Still, the number of genetic differences between a human and a chimp is about 10 times more than between any two humans.
. . They looked for genes that apparently have changed more quickly in humans than in chimps or rodents, indicating they might have been particularly important in human evolution. They found evidence of rapid change in some genes that regulate the activity of other genes, telling them when and in what tissues to become active. It would make sense that changes in these regulatory genes could have a broad impact on how organisms develop, playing a key role in human evolution, Waterston said.
. . With help from the chimp DNA, his team also uncovered several regions of human DNA that apparently contain beneficial genetic changes that spread rapidly among humans within the past 250,000 years. One area contains a gene called FOXP2, which previous work has suggested is involved in acquiring speech.
. . Svante Paabo of the Max Planck institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues report in the Science paper that genes active in the brain have changed more in the human lineage than in the chimp lineage. That wasn't the case for genes from other organs such as the heart and liver.
. . Researchers compared the human and chimpanzee versions of one region. Humans and chimps have been evolving separately for about 6 million years, so scientists reasoned that the comparisons would reveal genes that have become disabled in one species or the other during that time. They found five such genes on the chimp chromosome but none on the human chromosome, an imbalance Page called surprising. "It looks like there has been little if any gene loss in our own species lineage in the last 6 million years", Page said. That contradicts the idea that the human Y chromosome has continued to lose genes so fast it'll disappear in 10 million years, he said. "I think we can with confidence dismiss .... the 'imminent demise' theory."
Sept 1, 05: The human Y chromosome —-the DNA chunk that makes a man a man-— has lost so many genes over evolutionary time that some scientists have suspected it might disappear in 10 million years. But a new study says it'll stick around.
. . Researchers found no sign of gene loss over the past 6 million years, suggesting the chromosome is "doing a pretty good job of maintaining itself." That agrees with prior mathematical calculations that suggested the rate of gene loss would slow as the chromosome evolved.
. . The Y appeared 300 million years ago and has since eroded into a dinky chromosome, because it lacks the mechanism other chromosomes have to get rid of damaged DNA. So mutations have disabled hundreds of its original genes, causing them to be shed as useless. The Y now contains only 27 genes or families of virtually identical genes.
Sept 1, 05: Researchers from Rensselaer Polytechnic Institute and the University of Akron have used their knowledge of what makes geckos stick to create a carpet of super-sticky carbon nanotubes that could form the basis for future types of adhesives. In this case, science has even surpassed nature by producing bundles of nanotubes with an adhesive power 200 times greater than that of the gecko foot hairs.
. . The geckos' adhesive powers came not from chemistry, but from geometry --the size and shape of the tips of the gecko foot hairs. Each gecko foot is covered by half a million setae, tiny hairs 50,000 nanometers long. The length is often compared to the width of a human hair. Each setae branches off into hundreds of even more miniscule hairs, called spatulae, just 200 nanometers wide. The scientists discovered that an appropriate arrangement of setae and spatulae held the geckos to the wall by means of a type of an intermolecular attraction known as a van der Waals force.
. . They will now work toward building the nanotube carpets on a larger scale -- larger in this case being 1 centimeter square. Success in the lab could translate into adhesives that would work better in the vacuum of outer space than currently available adhesives. Astronauts might one day float through the void grabbing essential equipment with the help of gloves enhanced with nanotube-tipped fingers.
. . Or, if the adhesive force is strong enough, perhaps such gloves would even work here on Earth to let humans live out their fantasy of climbing walls like a spider --or even a gecko.
Sept 1, 05: The first ever chimpanzee fossils were recently discovered in an area previously thought to be unsuitable for chimps. Fossils from human ancestor were also found nearby.Although researchers have only found a few chimp teeth, the discovery could cause a shake-up in the theories of human evolution. "This is the first evidence in the fossil record that they coexisted in the same place in the past." Evolutionists may have to rethink what caused humans to become humans.
. . "For many years, people have used this kind of geographic split in environment as an explanation as an origin of humans and bipedalism", coauthor Sally McBrearty of the University of Connecticut said. "People have still retained this idea of a split geographic distribution of chimps and humans. This shows it certainly wasn’t true half a million years ago, and may not have been true before that. We need to look for another reason for the evolutionary split."
. . Hominid fossils were also discovered less than a kilometer from the lake shore where the chimp fossils were buried. More importantly, they were found in sediments of the same age as the chimp teeth -—about half a million years old.
. . Although not modern humans, these hominids were fairly advanced as evidenced by the wide variety of stone tools they used. "These represent an earlier species of human, relatives to modern humans, but not Homo sapiens", Jablonski said. "There’s some controversy over what this species is called. Most would call it an advanced form of Homo erectus. They looked like people and were a fairly sophisticated culture with various stone tools.
Pelagibacter accounts for a quarter of all organisms in the ocean.
Aug 24, 05: The Bangor Daily News had a timely editorial that maybe you could
read and muse on: "No one seems to think that a religious person engaged in the study of history must find a way that God rigged human events in order to cause the Civil War, the Industrial Revolution or the Holocaust. Yet curiously, that is exactly what many expect of a religious person engaged in the study of natural history —-they want to know how God could have ensured the success of mammals, the rise of flowering plants, the ascent of man."
. . Professor Miller makes the link with science: "Evolution answers the question of chance and purpose exactly the same way that history answers the questions about the course of human events."
Aug 24, 05: Killer whales which set traps to catch seagulls have become the third known animal species to possess "cultural learning" -- a skill which is transmitted to other members of their group. The gull-trapping trick was initiated by a four-year-old orca in a tank at Marineland at Niagara Falls in Ontario, Canada.
. . The mammal discovered he could lure seagulls into his tank by spitting regurgitated fish onto the water's surface. He then lurked below the surface, waiting for a gull to grab the fish, and then seized the bird in its open jaws.
. . After a few months of feathered snacks, the killer whale started to be joined his younger half-brother, and soon thereafter they were joined by their mothers, a six-month-old calf and an older male. The clever whales are able to catch three or four gulls on some days.
. . In June, researchers showed that wild dolphins off Australia taught each other to use sponges to protect their snouts while grubbing for food on the sea floor. And earlier this month, US scientists reported on two groups of chimpanzees whose members adopted rival methods to use a stick to coax food out of a feeder.
Aug 23, 05: When the tide is out, sea anemones sit quiet and still. It's a totally different scene once the tide rolls back in, as neighboring colonies of polyps wage all-out war.
. . Each colony is an "army", with the troops divided up into scout, warrior, and reproductive rankings, new research shows. As the tide starts to cover the colonies, "scouts" move to the border and look for empty space to claim. The "warrior" anemones – which are larger and well-armed with stinging cells – provide backup by inflating their arms and slapping at enemies, sometimes from four rows back off the front lines. Meanwhile, in the center of the colony, poorly armed anemones concentrate on reproduction, making sure there are enough "troops" to maintain the colony. And they coordinate all these complex behaviors without a single brain among them.
. . Sea anemones –-named after a terrestrial flower-– are water-dwelling, filter feeding animals. As members of the phylum Cnidaria, they are closely related to coral and jellyfish. Sea anemones have a foot which most species use to anchor themselves in sand or attach to rocks. Other species use their foot to attach to kelp, but some are free-swimming.
Aug 22, 05: Archaeologists in the former Soviet republic of Georgia have unearthed a skull they say is 1.8 million years old and part of a find that holds that oldest traces of humankind's closest ancestors ever found in Europe.
. . The Homo erectus skull was found earlier this month about 100 kilometers southeast of the capital, Tbilisi, in the same area where a jawbone believed to be the same age was found in 1991. They're a million years older than any widely accepted pre-human remains in Europe, have provided additional evidence that Homo erectus left Africa a half-million years or more earlier than scientists had previously thought.
Aug 22, 05: When given a choice between steady rewards and the chance for more, monkeys will gamble, a new study found. And they'll keep taking risks as the stakes rise and dry spells get longer. The research, in which scientists also pinpointed brain activity during the gambling, could provide insight into the human penchant for risk.
. . The male rhesus macaque monkeys were shown either of two lights on a screen. Looking at a "safe" light yielded the same fruit juice reward each time. Looking at the "risky" light meant a larger or smaller juice reward. In the first test, the average reward was the same over time regardless of which light they chose. The monkeys overwhelmingly preferred to gamble, even when the game was changed so that gambling yielded less juice over time. "There was no rational reason why monkeys might prefer one of these options over the other because, according to the theory of expected value, they're identical."
. . More work is needed to map the entire circuitry involved in the process, the scientists say. Then, studies could possibly be done to how brains process risk and reward.
. . In humans, it's thought that low levels of the neurotransmitter serotonin might make one more risk-prone and impulsive. Perhaps, the scientists say, future work will shed light on the source of pathological gambling, obsessive-compulsive disorder and even depression.
Aug 22, 05: Primate experts say they have proven that chimpanzees, like humans, show social conformity. By training captive chimps to use tools in different ways, they have shown experimentally that primates develop cultural traditions through imitation. This has long been suspected from observations in the wild, but has not been shown directly. It suggests that culture has ancient origins, scientists write.
. . Chimpanzees in West Africa, for example, use stones and pieces of wood to crack open nuts for food; but this has never been observed in chimps living in East Africa.
Aug 21, 05: Complex variation of the East African climate may have played a key role in the development of our human ancestors. Scientists have identified extensive lake systems which formed and disappeared in East Africa between 1 and 3 million years ago. The lakes could be evidence that global climate changes occured throughout this pivotal period in human evolution. The findings suggest that humans evolved in response to a variable climate.
. . Dr Martin Trauth of the University of Potsdam and his team were able to identify and date the pre-historic lakes by studying layers of soil along the Rift Valley in Kenya, Ethiopia, and Tanzania.
Aug 19, 05: A ten-year survey in Cameroon by scientists from the UK's Royal Botanic Gardens has turned up more than 200 previously unknown plants. The researchers have found a higher diversity of plants in the Kupe-Bakossi region than any other site in tropical Africa. Highlights include new species of coffee, spectacular orchids and new relatives of the fig. The researchers say their work has led to local conservation initiatives.
Aug 19, 05: Small but perfectly formed, Pelagibacter ubique is a lean machine stripped down to the bare essentials for life. Humans have around 30,000 genes that determine everything from our eye color to our sex but Pelagibacter has just 1,354, US biologists report. What is more, Pelagibacter ("ocean bacteria") has none of the genetic clutter that most genomes have accumulated over time. There are no duplicate gene copies, no viral genes, and no junk DNA. The spareness of its genome is related to its frugal lifestyle. The shorter the length of DNA that needs to be copied each generation, the less work there is to do.
. . Pelagibacter has even gone one step further. It has chosen where possible to use genetic letters - or base pairs - which use less nitrogen in their construction: nitrogen is a difficult nutrient for living things to obtain.
. . There are an estimated 20 billion billion billion Pelagibacter microbes scattered throughout the world's oceans.
. . There are organisms with smaller genomes --Mycoplasma genitalium has about 400 genes. But these are all obligate parasites or symbionts, relying on other organisms to do the jobs they have abandoned. Pelagibacter is entirely self-sufficient.
Aug 16, 05: Scientists are proposing reintroducing large mammals such as elephants, lions, cheetahs and wild horses to North America to replace populations lost 13,000 years ago. The scientists say that not only could large tracts of North America act as breeding sanctuaries for species of large wild animals under threat in Africa and Asia, but that such ecological history parks could be major tourist attractions. They proposed a second phase that would include reintroducing African cheetahs, lions and Asian and African elephants to large private parks.
. . "Africa and parts of Asia are now the only places where megafauna are relatively intact, and the loss of many of these species within this century seems likely."
. . They said the pronghorn antelope's remarkable speed must be due at least in part to the presence of the now extinct predatory American cheetah alongside it on North America's grasslands.
Aug 16, 05: The more we learn about the human genome, the less DNA looks like destiny.
. . As scientists discover more about the "epigenome", a layer of biochemical reactions that turns genes on and off, they're finding that it plays a big part in health and heredity. By mapping the epigenome and linking it with genomic and health information, scientists believe they can develop better ways to predict, diagnose and treat disease.
. . The epigenome can change according to an individual's environment, and is passed from generation to generation. It's part of the reason why "identical" twins can be so different, and it's also why not only the children but the grandchildren of women who suffered malnutrition during pregnancy are likely to weigh less at birth.
. . While predicted treatments run from diabetes and heart disease to substance abuse and schizophrenia, the most promising applications are in cancer. Research shows that some cancers follow from the deactivation of tumor-suppression genes. Last year, the Food and Drug Administration approved the first epigenetic drug, azacitidine, which treats a form of leukemia by reactivating those genes.
. . However, using drugs to target specific parts of the epigenome, which runs in tandem with our 6 billion base pairs of DNA, is extremely complicated. Fruit flies have no epigenomes.
. . Scientists need a large-scale map that shows how epigenetic patterns relate to disease. "If we knew those patterns", Baylin said, "you could predict which individuals are more at risk -- change their diets, change their exposures, use prevention. We could detect disease early and predict how people respond to drugs."
. . Making that map won't be easy. Not only does the epigenome change over time, it also differs in every major cell type, of which there are a couple hundred. Epigeneticists say this will be time-consuming but possible. It's begun, but 1% finished would be a massive overstatement.
. . In Europe, a consortium of public and private institutions is collaborating on the Human Epigenome Project, while mapping in the United States is scattered among a handful of companies and government-funded scientists.
Aug 15, 05: When it comes to fishing tasty termites out of their mounds, wild chimpanzees don't have the right stuff. Most, in fact, are southpaws. A three-year study of 17 wild chimps in Gombe National Park, Tanzania, found that 12 of them used their left hands when using sticks to probe for termites. Four were right-handed and one was listed as ambiguously handed.
. . Scientists have long debated whether nonhuman primates exhibit handedness. Because the hands are controlled by opposite sides of the brain, the finding could indicate that this brain division had begun as long as 5 million years ago, prior to the split between humans and chimpanzees.
. . Richard W. Byrne of the University of St. Andrews in the UK, who has reported on hand-preference in mountain gorillas doing complex tasks, said: "It now looks as if whatever gives a population skew to manually skilled behavior has its roots deep in the shared ancestry of humans and all other African great apes."
. . Byrne, who was not part of Hopkins' research team, said the findings show that with a big sample of chimpanzees, there is a slight but real group hand-preference when chimpanzees fish for termites, although many previous researchers with smaller samples had concluded there was not.
. . Among humans, a right-handed preference has been estimated for about 90 percent of the population. But Byrne noted that the figure "depends on asking people which hand they write with, and in studies of nonliterate people's behavior, much lower figures (for right-handedness) are found."
. . Most people, right and left handed, use the left hemisphere of the brain to process language. The argument has been made that if humans developed language after the split from apes, and language is related to handedness, then there shouldn't be handedness in apes.
Aug 11, 05: How does a flower know when to bud? Scientists have long known that it is the amount of sunshine that makes the difference. Now they have figured out how the leaves signal the flowers to form. A gene called FT in the leaves, discovered in the 1990s, is crucial to the process, but questions remained about how it delivered the message. The researchers have now found a protein called FD, which occurs in the tips of branches, that causes bunches of plant stem cells to form flower buds.
Aug 8, 05: Meteor strikes may have led to the extinction of some life on Earth, but they may have also contributed to the creation of life, according to a study. Geologists researching the crater left when the Haughton meteor slammed into what is now Canada's Arctic 23 million years ago found the impact created hydrothermal springs in the cracked rock and other conditions that would have made it easier for microbes to survive and evolve.
. . Osinski noted that the heaviest meteor bombardment of Earth happened about 3.8 billion years ago, around the same time that life on the planet is believed to have started.
Aug 8, 05: In the plant world, it's really dog-eat-dog. So much so that even two peas in a pod will fight each other to survive. The plant wars are fought largely underground. When the roots of two plants converge, plants somehow know how to tell the competition from themselves, and they grow accordingly.
. . A plant's roots will grow more robustly into competing territory, while not overcrowding its own soil. But how does a plant know the difference? Researchers cleaved one common garden pea plant into two, then let the pair grow side-by-side. The plants competed as if their separated twin was an alien, even though it was genetically identical. "This eliminated the possibility that the mechanism was based on specific chemical recognition."
Aug 8, 05: Microbes freeze-dried in Antarctica for two decades sprang to life when scientists added water, revealing yet another extreme ecosystem that shows life's incredible resiliency. The dormant bacteria lay in a mat in a glacial stream bed that hadn't been wet for about 20 years. Scientists diverted water into the channel to see what would happen. "These mats not only persisted for years when there was no water in the streambed, but blossomed into an entire ecosystem in about a week. All we did was add water." Earlier this year, scientists revived bacteria that had been frozen for 32,000 years.
. . The dormant microbes are cyanobacteria, which are gathered in a thin, rubbery, mat-like structure that can spread several meters across the streambed surface. Like plants, they rely on photosynthesis to survive. "After we diverted the water into the channel, photosynthesis began the same day and the mats became abundant within a week", McKnight said. "This showed us that they had been preserved in a cryptobiotic state."
. . Cyanobacteria have changed little since they emerged on the early Earth, scientists believe, and they're thought to have been among the first life forms on the planet.
Aug 8, 05: Two new species of lemur have been found in Madagascar, bringing the number of known species to 49. Lemurs are the closest living analogs to our ancient primate ancestors who lived about 55 million years ago. One-third of species are extinct. Remaining species are under threat from hunting and habitat destruction. Lemurs are considered the most endangered of all primates and live only on Madagascar which has evolved in isolation for 165 million years. As a result, the island is now home to mammals, birds and plants that exist nowhere else on our planet.
. . The first new species is a giant mouse lemur known as Mirza zaza. It has a long bushy tail and is about the size of a grey squirrel. Until now, scientists believed only one type of giant mouse lemur existed, split into two populations in the west and the north of the island. But morphological, genetic and behavioral data shows they are in fact distinct species which diverged about two million years ago.
. . The second new species is a type of mouse lemur, of which nine species are now known. Microcebus lehilahytsara, or Goodman's mouse lemur, lives in eastern Madagascar's rainforest. It is little bigger than a mouse, with short, rounded ears and a white stripe on its nose.
Aug 10, 05: Horseweed was once merely a nuisance to farmers —-hard to pull out, quick to sprout back after cutting, and capable of towering over tractors. Now, it's becoming a full-blown nightmare worthy of an agricultural horror flick: scientists in California have found clusters of the weed that are resistant to scores of herbicides, leaving farmers to fight an increasingly formidable and costly foe. Roundup wasn't withering the weed any more.
. . What makes the horseweed adaptation such a nuisance is how fast it reproduces and how big it grows, stretching 10 or 12 feet tall, sucking up scarce water and nutrients. As a relative of the dandelion, each weed produces up to 200,000 tiny airborne seeds a season on fluffy yellow flowers.
Aug 8, 05: Scientists have discovered one of the most intricate examples of convergent evolution with the help of South American "poison" frogs and ants and their cousins in Madagascar. (An odd fact for smokers: one Madagascan frog studied was found to have nicotine in its system!)
. . Poison frogs can't make their own poison --they steal it from ants. Poison frogs secrete a variety of chemicals called alkaloids to create a poisonous defense against predators. Since they can't produce alkaloids on their own, these frogs maintain a steady diet of specific alkaloid-rich ants to keep up their defense.
. . Now, Valerie Clark of Cornell University and her colleagues have detailed two instances of convergent evolution --the process in which organisms not closely related independently acquire similar characteristics while evolving in separate ecosystems-- between frogs and ants on two continents.
. . First, species of ants high in alkaloids had to evolve on two separate continents. Then the frogs had to develop a resistance to the alkaloids--instead of spitting out the ants or passing the alkaloids through their systems, the frogs became able to keep their ant dinners down. Then they evolved to make use of the alkaloids themselves. Also, both the frogs in South America and Madagascar evolved to have bright "don't-eat-me" skin colorings, the final step in a remarkable tale of evolution.
. . Up until now, scientists have mainly studied frogs from South America and Australia. But Clark and her colleagues showed that the Madagascan frogs needed the same types of food to be poisonous. They examined the stomach contents of 15 frogs from the class Mantella and found that alkaloid rich ants made up 74% of their food intake. Not only that, but they found nicotine --the same chemical found in cigarettes-- in one Mantella baroni frog. Nicotine is produced by plants and can sometimes be found in animals that eat these plants. But no nicotine-producing plants grow in the area where this frog was found. Other characteristics the Madagascan frogs share with their South American cousins include terrestrial eggs, small body size, and toothless jaws.
. . Scientists have long known that frogs rely on a diet of ants, beetles, and millipedes to produce their poison. When poison frogs are captured and kept in captivity, they retain skin alkaloids for years. But they can't make more without eating the right types of ants. Frogs kept in captivity and fed a steady diet of flies, for example, don't secrete alkaloids.
Aug 8, 05: DNA taken from the teeth of ancient sabertooth cats showed the distinctive-looking animals were cousins of modern-day cats but not direct ancestors, scientists said. And they also shot down a theory that cheetahs may have originally evolved from a similar-looking North American ancestor. "Our results show that the sabertooths diverge early and are not closely related to any living cats."
. . Sabertoothed cats went extinct about 13,000 years ago, as did many other large cats that once roamed the North American plains, such as the Yukon scimitar-toothed cat, the American lion-like cat or Panthera atrox and a cheetah-like cat called Miracinonyx trumani. The only large cats that survived in the Western Hemisphere were the puma, also commonly known as a mountain lion or cougar, and the jaguar.
. . Researchers managed to get some DNA from a sabertooth's bones, a bit from a related Yukon scimitar-toothed cat and a sample from Miracinonyx bones found in Wyoming.
. . The cat that resembled an early cheetah was not in fact a cheetah but a relative of the modern-day puma. It appears to have evolved from a puma-like ancestor, presumably in response to similar ecological pressures", the researchers wrote. In other words, it chased antelope on the rolling plains of the Midwest just as modern cheetahs do in the African savannah. "However, the mitochondrial sequence analysis together with recent fossil data suggests that they originated in the Old World and that a puma-like cat then invaded North America around six million years ago," the researchers wrote. "Around 3.2 million years ago, this ancestor diverged into Miracinonyx and Puma, which is broadly contemporaneous with increasing prairie in North America."
Aug 6, 05: When loosestrife covers a wetland with purple flowers, it flaunts the invasive power of alien plants. While scientists have barely begun to understand the full ecological impact of alien plant invasions, the global mixing of plants and animals now going on could be a major channel for unplanned environmental change.
. . The ecological alterations that an aggressive alien may bring vary. It can co-opt soil microbes to enhance its growth. It can deny native animals their natural food and shelter. It can create a new wildfire hazard as alien grasses are doing in some North American deserts. New research shows it can even help a new insect species to emerge.
. . Research on one familiar alien, the Japanese honeysuckle, reported last week in Nature magazine, illustrates this point. People brought the bushy honeysuckle to North America more than 250 years ago. The US Department of Agriculture began promoting it as a garden and wildlife plant in 1880. The plant, which produces a berry-size fruit, is now part of the wild flora of the Northeastern United States.
. . The tephritid fruit fly loves this kind of plant. In fact, there's a fly species specifically adapted to exploit each species of berry-producing plants. For instance, the blueberry fly goes through its entire life cycle on blueberry bushes. It can't live on any other type of plant. That's how the fly-plant relationship has evolved naturally.
. . The Japanese honeysuckle also has its fly. But that fly didn't originate with the plant. A Pennsylvania State University research team traced its ancestry to a hybrid produced by flies that live on blueberry and snowberry plants, respectively. Normally, such a hybrid fly strain would die out. It can't compete with either of its parent species on their host plants. Honeysuckle offered a niche with no such competition where the hybrid became a new species. The family outcast found an empty house on the block and moved in.
Extremophiles, a biological curiosity here on Earth, could represent the most frequent form of life in the universe. The first of these sturdy organisms to be discovered, a thermophile, was found in the late 1960s in Yellowstone National Park, hanging out in one of the hot springs. It was a bacterium.
. . Thermus aquaticus not only withstood, but thrived, in temperatures above 71 C. One, Pyrolobus fumarii, can stand water of 113C. Other extremophiles operate smoothly in below-freezing cold (psychrophiles), highly acid or base solutions (acidophiles and alkaliphiles), heavy-duty brines (halophiles), and in circumstances of crushing high pressure or dusty dryness (piezophiles and xerophiles). There are varieties that can shrug off nuclear radiation, or dwell well in aviation fuel.
. . There are two fundamental strategies: erect a barrier against the elements, or change your metabolism. Some halophiles protect themselves from a saline environment by increasing the concentration of salts in their innards. Psychrophiles come equipped with special proteins to adapt their lifestyle to the cold. Some of these proteins act as antifreeze. Deinococcus radiodurans, which boasts highly sophisticated DNA repair within its tiny cell walls, is able to recover from exposure to massive doses of molecule-busting, high energy radiation.
. . It is, in fact, currently fashionable to argue that life on Earth may have begun, not in Darwin's "warm little pond", but in a seething, scalding and turbulent sub-ocean geyser, where chemical reactions are fast.
Aug 3, 05: By examining microscopic marks on fossilized teeth, scientists have pieced together the diets of two ancient prehumans. The small, slender Australopithecus africanus, which lived between two and three million years ago, appear to have eaten mostly soft foods like fleshy fruits, young leaves and perhaps some meat.
. . Paranthropus robustus was about the same size as A. africanus, but lived about two million years ago and had much larger, flatter teeth, a thicker jaw and bigger, heavier chewing muscles. Its teeth showed the signs of harder, more brittle foods like nuts, seeds, roots and tubers --the types of food that grow in the open savannah. But P. robustus also showed signs of having eaten the softer foods enjoyed by A. africanus, possibly explaining how P. robustus survived in the savannah.
. . "In the same way, there's a lot of overlap between chimpanzees and gorillas --their anatomy is different, but most of the time they eat the same foods when they live together. All these early hominids probably preferred to eat fruits -- they taste good and are high in energy", Ungar said. "I would say that probably both would take meat when they could get it, similar to chimpanzees today."
. . To determine the diets of these ancient hominids, Ungar compared fossil teeth to the teeth of modern day primates with known diets. Different foods make different grooves and patterns on teeth, so it is possible to figure out an animal eats by looking at these patterns. To do this, Ungar and his colleagues used a special microscope and computer program to analyze microscopic tooth wear. "This new technique cuts out observer error and allows us to look at variation and overlap between species", Ungar said.
. . A. africanus branched off the line leading to humans about three million years ago. About million years after that, P. robustus branched off the line to Homo. While A. africanus went extinct about half a million years before P. robustus hit the scene, most scientists believe that P. robustus overlapped with early Homo species.
Aug 1, 05: Tiger moth caterpillars have been seen medicating themselves to treat a nasty influx of parasites. Scientists found the caterpillars' sense of taste actually changed when they became infected with parasites. Instead of avoiding certain alkaloid plants, the caterpillars actually developed a fondness for them. This change in diet helps to beat the creatures' parasite infection, the researchers report.
. . The parasitic flies lay eggs on the surface of the caterpillars' skin which, on hatching, bore into the larvae's flesh. The parasite's objective is to feast on the generous supply of live tissue, before it pupates and bursts out of the dead caterpillar.
. . Instead of eating a wide range of plants, which the tiger moth lava usually does, the caterpillar becomes much more specific: it homes in on plants that are particularly toxic to its parasites. These plants, such as woolly plantain, produce chemicals known as pyrrolizidine alkaloids and iridoid glycosides. Not only do these chemicals wash through the caterpillar's body, making it an unattractive meal, they also collect in its skin, deterring future invaders.
. . "It's still a mystery how they do it", Dr Bernays said. "But the result for the caterpillars is the same: they can survive because they find the protective plants more tasty."
Aug 1, 05: A bird species found in some parts of Western Alaska is believed to emit a natural mosquito repellent with properties similar to DEET, the key ingredient in many commercial repellents. Hector Douglas, a University of Alaska Fairbanks researcher, said he made the discovery in the feathers of the crested auklet after applying a little scientific intuition and sacrificing some of his own blood.
. . The birds feed en masse on zooplankton in the ocean and return as a group, 1 million strong. As they began landing, the first clue was right under his nose. "The birds would come down and have [a] citrus smell..." The smell reminded him of a research paper he'd read about birds that rubbed citrus peels in their feathers to help ward off pests.
. . To test his theory, he went into the laboratory with a few auklet feathers. An analysis showed him the chemicals that make up the auklet's "odorant." Most are available commercially. He then tested their repellent properties using mosquitoes specially bred at a research lab in Florida for their aggressive tendencies. Douglas dabbed test samples on filter paper, attached that paper to his hand, then put it in a cage with hungry mosquitoes. It was clear the auklet samples kept mosquitoes away.
July 29, 05: The remotest depths of the Arctic ocean are surprisingly full of life, including previously unknown species of jellyfish and worms, a scientific team which just finished exploring the area said. The scientists, led by the University of Alaska, used robot submarines and sonar to probe an isolated 3,800-meter basin off Canada's Arctic coast where they fear species could be at risk from global warming.
. . "We were surprised by the abundance and the diversity of life in this environment. Even at a depth of 3,000 meters we found animals on the sea floor. "Some of the species that we saw are completely new to science, they have not been described in any area of the earth so far." The species are a jellyfish and three kinds of benthic bristle worms. The team also found unexpectedly high numbers of cod as well as the first squid, octopus and flea-like crustaceans ever seen in an icy environment.
. . The team said the data would help measure the impact of climate change and, should polar caps continue receding, the damage done by increased energy exploitation, fishing and shipping. "This is a benchmark and we hope that in the next 10, 20 or 30 years these kinds of studies will be repeated to see whether any kinds of changes have occurred in the composition and the abundance of animal life."
. . U.N. studies say the Arctic could be largely ice-free in summer by 2100 because of global warming, blamed mostly on gas emissions from cars, power plants and factories. The scientists say that if the northern polar cap melts, more southerly species could enter Arctic waters and disrupt the ecology.
. . The team also said explorers would carry out similar studies in the Southern Ocean around the Antarctic, where conditions are much less settled than in the Canada Basin. "Scientists now theorize the swirling Southern Ocean current is an evolutionary caldron, upwelling Antarctic nutrients and mixing life forms from the Pacific, Indian and Atlantic oceans, returning them in centrifuge-like fashion."
Capuchin monkeys, a new study says, understand that their image in a mirror is not a stranger, but they don't know it's their own.
July 28, 05: Unhatched dinosaur eggs dating back 190 million years --the beginning of the Jurassic Period-- carried fully developed embryos that would have been born clumsy and helpless, scientists said. Their finding suggests even the earliest dinosaurs tended carefully to their young. It also raises questions about how the giant four-legged dinosaurs called sauropods evolved.
. . "These animals do not have any teeth, and since they are ready to hatch, that is strange." They must have been fed by the mother. That would be oldest evidence of parental care.The eggs come from a dinosaur called Massospondylus, one of a group called prosauropods that later evolved into the giant sauropods such as apatosaurus, previously known as brontosaurus.
. . The fossil eggs were found in South Africa in 1978, but scientists have only now been able to open and study them properly. Reisz's team used tiny tools to do it. "We have essentially miniature jackhammers. They are pencil sized", he said. "And we use very delicate dental tools." Working under a powerful microscope, Reisz's team had to design a vibration-free table to work on. "When somebody slammed a door in the building, my technician who preparing this felt that."
. . When they got the eggs open, they could see the baby dinosaurs were just about to hatch. The young are altricial (helpless). In fact, egg fragments were all around, suggesting that at least one did. And the babies did not look like the parents. Adult prosauropods were slender and two-legged. The babies looked more like the dinosaurs that developed later, and they looked like the babies of animals such as birds and mammals, as opposed to the small but adult-proportioned young of reptiles.
. . A typical adult Massospondylus was 5 meters long. The best-preserved egg is just 6 cm long. The embryo, curled up inside, is about 15 cm in length. An analysis of the embryos suggests they were born walking on four legs with short tails, long forelimbs and big heads. To morph into their adult shape --walking on two legs with long tails, short forelimbs and small heads-- their various features must have grown at different rates.
. . Scientists once thought the group walked only on two legs, then simply dropped to four when they evolved into heavier beasts. But the new findings may challenge that assumption by showing that even prosauropods had some tendency to walk on four legs.
. . "It starts out as a quadriped and becomes, as it grows up, as a biped. There are very few examples in nature that do this", he said. One example, however, is a human baby!
July 27, 05: Although they capture the imagination, the liger (lion/tiger), the wholphin (whale/dolphin), and the zonkey (zebra/donkey) are all hybrids that are unlikely to be found in the wild.
. . But new research into a certain fruit fly may be evidence that hybrids are more common in nature than thought. Like the mule (a cross between a male donkey and a female horse), many hybrids are unable to reproduce because the parents have different numbers of chromosomes. Some hybrids get around these difficulties by cloning themselves asexually.
. . "People used to think of hybridization as a dead-end process", said Dietmar Schwarz from Pennsylvania State University. "We basically are proposing that it should be considered as a possible means to speciation in animals."
. . In the tree of life, this would count as a "fork" between two branches. But "knots" in the tree are also possible, where two different species have mated --creating an offspring that is different from the parents. Even assuming that they can reproduce, the survival of these hybrids relies on them being reproductively and ecologically isolated.
. . Hybrids also need to have their own separate niche, or ecologic isolation, otherwise they will likely be out-competed by their parent species. Because satisfying both these conditions is hard to imagine, most biologists have neglected hybridization as a viable origin for new species.
. . But Schwarz and his colleagues have found a fruit fly hybrid, which apparently was able to distance itself from its parents. The success of this hybrid is due to the fact that it and all its close relatives are host-specific parasites. The females of this type of fruit fly lay their eggs in one --and only one-- kind of fruit. The maggots feed on the host fruit and then leave to become adult flies. But they return to the host plant (apparently recognizing the odor) to mate. The hybrid fly achieved reproductive and ecologic isolation by picking a host --in this case, the honeysuckle-- which is different from its parents.
. . Genetic analysis of the hybrid, which the scientists deem the "Lonicera fly", shows that it is a cross between the blueberry maggot and snowberry maggot flies. This new species took full advantage of the new niche supplied by the non-native honeysuckle.
. . Although this is only one specific case, the researchers point out that hybridization could be more prevalent, as there are a lot of animals --like fleas and worms and parasitic wasps-- which could isolate themselves by switching hosts.
July 27, 05: 150 years after Darwin's most important work, scientists have found the tortoise Geochelone nigra, found on the Galapagos island of Santa Cruz, is not one species but three. The new research employed DNA analysis.
July 25, 05: Can you & your mate stick together so tightly that your tissues fuse and your blood and nutrients mingle, never letting go? Not a likely vow --unless you're one of a select bunch of deep-sea-dwelling fish plying the world's oceans.
. . University of Washington professor Ted Pietsch is the world's expert on these fish, notable for engaging in "sexual parasitism" --a phenomenon in which tiny male fish latch onto relatively gigantic females, melding into them. "It's such a vast open area out there to find a female", Pietsch said. When they do meet up, "he essentially becomes part of her. He resigns himself to a life of attachment."
. . This extreme degree of commitment is a clever strategy for guaranteeing the creation of the next generation of creatures living in sparsely inhabited, pitch-black waters. The bound fish mature together and spawn in sync, the eggs and sperm released in close proximity.
. . The fish are amazing in countless other ways. There are more than 160 species in the group, though only about two dozen are known to make permanent pairings. The fish live in complete blackness more than twomiles below the surface of the water, in crushing pressure and temperatures close to freezing. Despite living far from seasonal clues such as day length and weather conditions, the fish know to spawn in early summer. When the females release their eggs, they're in a clump riddled with canals. The canals suck up the seawater and sperm like a sponge, floating the clump to the ocean's surface. There, the baby fish hatch and feed on plankton. After a few months, they make the return trip into the abyss.
. . Females grow a lure, sprouting from their heads, to attract both dinner and a date. The bait is different among species --some have feathery tendrils, others are more of a little club. The lure contains glowing bacteria that invade the fish as they grow. The tendrils act like a fiber optic, channeling the light from the blob of bacteria at one end of the tendril to its tip, which glows and can be flashed in patterns like an SOS beacon.
. . Its teeth are hinged and bend inward to help it catch and hold prey. It's only a few inches long, with sandpapery skin, though females of some species measure over a meter. Males of one variety are believed to be the smallest full-grown vertebrates on the planet. They measure 6 millimeters --about the length of a ladybug. The males often have large eyes and a disproportionately large nose, used to sniff out females. It's a great trait, because for some males, finding a mate is literally a matter of life or death. The fish aren't able to eat and must attach to a female within about three months of hatching, or die. When a lucky fellow finds his gal, "he turns around and bites her somewhere", Pietsch said. "It sounds horrible." The couple-for-life grow together --which poses yet another scientific conundrum. Human doctors struggle to keep patients from rejecting transplanted donor organs, yet the female fish doesn't reject the male parasite as foreign.
July 25, 05: Now, there's a scientific theory explaining, at least in part, why cats have such snobby eating habits: genetics. Researchers found a dysfunctional feline gene that probably prevents cats from tasting sweets, a sensation nearly every other mammal on the planet experiences to varying degrees.
. . Each human taste bud is comprised of 50 to 100 receptor cells representing the five major taste sensations: salty, sour, sweet, bitter and umami (the taste of the food additive MSG and fermented soy products, among other foods).
. . Researchers took saliva and blood samples from six cats, including a tiger and a cheetah and found each had a useless gene that other mammals use to create a "sweet receptor" on their tongues. The gene in question does not produce one of the two vital proteins needed to form the receptors. Most mammals' sweet receptors are created by two proteins, one of which cats are missing. Many animals in the carnivore family like sweet things, including bears, dogs, raccoons and others.
. . "What we still don't know is -- which came first: carnivorous behavior or the loss of the T1R2 protein? With regard to the gene, is this a case of use it or lose it?"
July 23, 05: Why one species branches into two is a question that has haunted evolutionary biologists since Darwin. Given our planet's rich biodiversity, "speciation" clearly happens regularly, but scientists cannot quite pinpoint the driving forces behind it. Now, researchers studying a family of butterflies think they have witnessed a subtle process, which could be forcing a wedge between newly formed species.
. . The team, from Harvard University, US, discovered that closely related species living in the same geographical space displayed unusually distinct wing markings. These wing colors apparently evolved as a sort of "team strip", allowing butterflies to easily identify the species of a potential mate. This process, called "reinforcement", prevents closely related species from interbreeding thus driving them further apart genetically and promoting speciation. Although scientists have speculated about this mechanism for years, it has rarely been witnessed in nature.
. . For speciation to occur, two branches of the same species must stop breeding with one another for long enough to grow apart genetically. The most obvious way this can happen is through geographical isolation. But geographical isolation is not enough to explain all speciation. Clearly, organisms do sometimes speciate even if there is no clear river or mountain separating them.
. . The other mechanism that can theoretically divide a species is "reproductive isolation". This occurs when organisms are not separated physically, but "choose" not to breed with each other, thereby causing genetic isolation, which amounts to the same thing. Reproductive isolation is much hazier and more difficult to pin down than geographic isolation, which is why biologists are so excited about this family of butterflies. Dr Kandul and his colleagues found that if closely related species of Agrodiaetus are geographically separate, they tend to look quite similar. That is to say, they do not display a distinctive "team strip".
. . But if similarly closely related species are living side-by-side, the researchers noticed, they frequently look strikingly different --their "teams" are clearly advertised. This has the effect of discouraging inter-species mating, thus encouraging genetic isolation and species divergence.
. . "This butterfly study presents evidence that the differences in the male's wing coloration is stronger [when the species share a habitat] than [when they do not]." The reason evolution favors the emergence of a "team strip" in related species, or sub species, living side-by-side is that hybridization is not usually a desirable thing. Natural selection will favor ways of distinguishing the species, which is why the clear markings exist. "For me, this is a big discovery just because the system is very beautiful," said Dr Kandul. "As much as we can we are showing that [reinforcement] is the most likely mechanism."
July 22, 05: Dragonflies and damselflies belong to suborders of the same class of insect. Damselflies are more fragile and have widely separated eyes, compared to dragonflies whose eyes meet on top of the head. A damselfly's wings and hind wings are similarly shaped and folded on its back when it is resting; a dragonfly's hind wings are broader at the base than its forewings and it keeps them spread out at its side when at rest.
. . Worldwide, scientists have found 2,874 species of dragonflies and 2,700 species of damselflies —-but those numbers are constantly changing as new species are found and similar species are combined. There are 316 species of dragonflies in the United States —-the largest, the Giant Darner, is about 4 inches long, although its wingspan is not as impressive as some other U.S. dragonflies-— plus, 131 damselflies.
. . Dragonflies are predators, but their diet is limited to other bugs: mosquitoes, gnats, flies, flying ants, termites, butterflies, even damselflies and other dragonflies. They do not sting or bite, and contrary to the old wives' tales, dragonflies do not sew up a person's lips so they can't eat and starve to death.
July 21, 05: Tiny, snail-eating caterpillars found in Hawaiian rain forests tie up their prey with sticky silk and snack on them at leisure, surprised scientists said today. It is the first time that caterpillars that eat snails or any other mollusk have been found. And while caterpillars of all kinds spin silk to make cocoons, this is the first time one has been seen to use it as spiders do to capture prey. The caterpillars do not eat plant foliage, even when starving.
. . The caterpillars join a range of unusual Hawaiian fauna, including spiders that impale their prey in flight.
July 20, 05: Australopithecus afarensis, the early human who lived about 3.2 million years ago, walked upright, according to an "evolutionary robotics" model. The model, which uses footprints to predict gait, suggests "Lucy", as the first fossil afarensis was called, walked rather like us. The ancient hominid had many features reminiscent of her early ape ancestry, but she also carried hints of her future decendents. Her jaw was protruding and her forehead sloped back; but she seemed human too, her posture being more upright than that of a chimpanzee.
. . Twenty-five years ago, some footprints were found in Laetoli, Tanzania. The lonely path, trodden by at least two individuals walking side by side, was preserved immaculately in volcanic ash. It is thought to have been left by a pair of Australopithecus afarensis. Some felt the prints suggested a human-like gait but others were not convinced.
. . Now, a team of scientists from around the UK have used computer robotic techniques to work out the most energy efficient gait for afarensis based on Lucy's skeleton and the Laetoli footprint trails. "Assuming that the early human relative Australopithecus afarensis was the maker of the Laetoli footprint trails, our study suggests that by 3.5 million years ago at least some of our early relatives --despite their small stature-- could sustain efficient bipedal walking at absolute speeds within the range shown by modern humans."
July 18, 05: An expansive ecosystem of knee-high mud volcanoes, snowy microbial mats and flourishing clam communities lies beneath the collapsed Larsen Ice Shelf in Antarctica, say researchers. The discovery made in February in a deep glacial trough in the northwestern Weddell Sea. Such sunless, cold-vent ecosystems have been found elsewhere — near Monterey, Calif., in the Gulf of Mexico and in the Sea of Japan —-but never in Antarctica.
. . The discovery was accidental. U.S. Antarctic Program scientists were in the northwestern Weddell Sea investigating the sediment record in a deep glacial trough twice the size of Texas. The trough was unveiled in the 2002 Larsen B ice shelf collapse. Toward the end of the expedition, the crew recorded a video of the sea floor. Later analysis of the video showed the clams and bacteria growing around mud volcanoes. Since light could not penetrate the ice or water, these organisms do not use photosynthesis to make energy. Instead, these extreme creatures get their energy from methane.
. . Domack hopes to find new species and that this discovery will open the door to future Antarctic expeditions, specifically into Lake Vostok, a freshwater lake that sits two miles below the surface.
. . The discovery will certainly help scientists better understand the dynamics of life in such an inhospitable setting 2,800 feet below the sea surface, he said. The ice shelves cover nearly 580,000 square miles of sea floor —-an area equivalent in size to the Sahara Desert or the Amazon River basin.
. . "It looked like a thin slice of cheese had been laid over the sea floor. Sporadically placed, there were mud mounds, little volcanoes, two- to three-feet high and several feet across, spewing out fluid and mud particles", Domack said. Surrounding the mud volcanoes were clusters of large clams. The ecosystem covered about a 3-square-mile area.
. . The ice shelf likely provided a protective shelter, allowing the chemical habitat to thrive on the sea floor over the centuries. Now that the ecosystem has been exposed, it is imperiled by fattening deposits of sediment produced through erosion run-off from the advancing glaciers and from dying algae settling to the bottom. The sediment is not only burying the ecosystem, but it is also introducing carbon and other new chemicals into the methane-powered environment, he said. "It is an ecosystem in flux, in change, and that's a rare opportunity for scientists."
Microbes make up over a half of all Earth's biomass.
July 16, 05: Scientists have discovered how migrating locusts avoid the danger of flying over the sea. Experiments show the insect is capable of detecting the polarized reflections of large bodies of water. This means it can switch flight paths when it encounters water, boosting its chances of survival.
. . The idea for the study came from observations by volunteers of an outbreak of locust migration near the Gulf of Aqaba last November. Swarms crossed the length of the Sahara desert to reach Egypt via the Sinai desert. But instead of crossing the 3-5km wide gulf, they turned north and flew over land, turning back towards the shore if they veered over water. The research could lead to novel deterrents.
. . Many animals have eyes that are sensitive to polarized light: basically light reflected off a flat surface. "For a migrating desert insect, water presents a potential hazard and large bodies of water, such as the sea, are especially dangerous."
July 16, 05: Sharks have provided inspiration for several useful technologies. One new idea has captured the interest of the U.S. Navy. Shark skin has been used by many cultures as sandpaper. It's kept shipmates safe in slippery-when-wet conditions. Swimsuits modeled on shark skin are said by Speedo to reduce drag by up to 4%.
. . Now, research by two separate groups could lead to synthetic shark skin that would make ships and submarines faster less expensive to operate. The growth of barnacles, mussels, algae and other organisms adds to fuel costs for the military and shipping industry, increasing drag by up to 15%, scientists say. In the industry, it's called bio-fouling.
. . The Navy spends about $600 million each year to power ships and submarines. At least $50 million of that cost is directly related to bio-fouling. Paints laced with deadly biocides curb the problem, but they are also toxic to other marine life.
Some fish, and also whales, are fouled by hitchhiking marine life. But not sharks.
. . Scientists have figured out that the secret to clean sharks is in the complex design of their scales. Shark scales are made of a hard material called dentin. Basically, the scales are tiny teeth. They all point backward, so a shark would feel smooth if you dared to stroke it from head to tail, but rough if you ran your hand the other way. Studies have found that the scales act as armor for a shark and also create tiny vortices that reduce drag to make them faster. The scales also allow sharks to swim silently compared to other fish that generate considerable noise when they ply the water.
. . Norwegians applied real shark skin to the soles of their boots to prevent slippage on wet ship decks. While simpler in design than shark scales, the ship skin reduced bio-fouling by 67% in tests. Mussels and barnacles make some of the strongest adhesives known (other scientists try to mimic the properties to make better household glue). But the glue of a barnacle, Liedert found, can only penetrate so far into a rough surface, explaining why the scales prevent them from sticking.
. . With the fake skin applied, a ship moving at 4-5 knots becomes self-cleaning, removing most organisms.
July 14, 05: The insertion of human stem cells into monkey brains runs a "real risk" of altering the animals' abilities in ways that might make them morally more like us, scientists said today. A panel of 22 experts --including primatologists, stem cell researchers, lawyers and philosophers-- debated the possible consequences of the technique for more than a year.
. . While the group agrees it is "unlikely that grafting human stem cells into the brains of non-human primates would alter the animals' abilities in morally relevant ways", the members "also felt strongly that the risk of doing so is real and too ethically important to ignore."
. . In the case of Alzheimer's research, for example, grafting human stem cells into a monkey brain would be designed to reinstate lost memory function, but "we cannot be certain that this will be the only functional result", the report concludes.
. . There was "considerable controversy" within the group, which disagreed on whether such experiments, some already underway, should proceed. Other experiments using the technique are underway. The work is largely pointed toward finding cures for Parkinson's disease, Lou Gehrig's disease, and other human afflictions.
. . Similar research has been done with other animals. In one project, scientists plan to inject a mouse with human brain cells. But bioethicists are not as concerned that a mouse could get morals. [Are you too, rather amazed at this?! Is it a ridiculous ego-trip for humans? ]
July 13, 05: A newfound deep-sea relative of the jellyfish flashes glowing red lights on twitching, stinging tentacles to lure fish to their deaths more than a mile below the surface. The discovery is odd, because scientists had figured deep-sea animals can't see red light, since they live where sunlight doesn't reach and therefore have no evolutionary reason to detect the color. The transluscent, fragile creature is the first marine invertebrates ever found that produce red light.
. . In bioluminescence, a living thing converts chemicals into light much like the glow sticks. It's almost exclusively the domain of sea creatures. One of the handful of exceptions is the firefly.
July 13, 05: Sex was once thought to be the domain of higher life forms. But now a common fungus --one that causes deadly infections in humans-- appears to reproduce sexually. The fungus, aspergillus fumigatus, has also been linked to asthma. Scientists always thought it reproduced asexually, a method of simple cell division used by many microbial creatures.
. . A new study finds the fungus has a series of genes required for sexual reproduction. An analysis of 290 specimens revealed nearly equal proportions of two different sexes or 'mating types,' which in theory could have sex with each other.
. . "The possible presence of sex in the species is highly significant as it affects the way we try and control disease", said David Denning of the University of Manchester. "If the fungus does reproduce sexually as part of its life cycle, then it might evolve more rapidly to become resistant to antifungal drugs --sex might create new strains with increased ability to cause disease and infect humans."
. . The study also found that genes had been, or were being, exchanged between individuals of the fungus and that some key genes involved with detecting a partner were active in the fungus.
. . "Taken as a whole, the results indicate that the fungus has a recent evolutionary history of sexual activity and might still be having sex so far 'unseen' by human eyes."
July 13, 05: Dinosaurs may have been fierce predators, but they had a respiratory system similar to modern birds such as the sparrow, scientists said. Ancient beasts such as the mighty Tyrannosaurus rex were thought to have had lungs similar to crocodiles.
. . "The pulmonary system of meat-eating dinosaurs such as T.rex in fact shares many structural similarities with that of modern birds, which from an engineering point of view, may possess the most efficient respiratory system of any living vertebrate inhabiting the land or sky", said Leon Claessens, of Harvard University in Massachusetts. They compared dinosaur bones in museums in the US, Germany and England with modern birds. They looked at how the skeleton related to the air system in areas such as the neck and chest.
. . The researchers found that dinosaurs had a respiratory system with the potential to support elevated rates of metabolism. Although it is not identical to birds, O'Connor said it is nothing like the crocodile system. "What was once formally considered unique to birds was present in some form in the ancestors of birds", he added. Recent research suggests some dinosaurs may have had feathers and incubated their eggs.
. . Claessens and O'Connor said their research does not mean dinosaurs were habitually warm-blooded. They believe the creatures were somewhere between what scientists describe as warm and cold blooded animals.
July 13, 05: Trying to swat a fly can be among the most frustrating household activities. Now scientists know why it is so hard. The fly's escape secret: It jumps rather than just trying to fly.
. . They dropped black disks from different angles, each on course to squash a fly. She videotaped the scenes. The video revealed that flies jump directly away from the incoming objects, using both their legs and wings. The results suggest the brain initiates a take-off sequence that involves a "giant fiber pathway" of nerve impulses to the wings and legs.
July 6, 05: German and U.S. scientists have launched a project to reconstruct the Neanderthal genome, the Max-Planck Institute for Evolutionary Anthropology said. "Firstly, we will learn a lot about the Neanderthals. Secondly, we will learn a lot about the uniqueness of human beings. And thirdly, it's simply cool", Rubin said.
July 8, 05: A parrot has grasped the concept of zero, something humans can't do until at least the toddler phase, researchers say. Alex, a 28-year-old African gray parrot who lives in a lab at Brandeis University in Massachusetts, has a brain the size of a walnut. But when confronted with no items on a tray where usually there are some, he says "none."
. . Zero is thought to be a rather abstract concept even for people. Children typically don't grasp it until age three or four, Brandeis researchers say. Some ancient cultures lacked a formal term for zilch, even as recently as the Middle Ages.
. . The researcher was working with him on a number-comprehension study. She knew he could look at a tray of green and blue balls and blocks and tell researchers how many of the objects were blue blocks. This "suggested it wasn't a simple associative mechanism, but we had to prove it", Pepperberg said, as he wasn't just seeing three blobs of something and counting it as three. Rather, there might be 18 items on a tray, and he'd have to separate out the green blocks and balls from blue ones.
. . They began giving Alex trays with various quantities of blue, orange and purple blocks. He would be asked something like, "What color three?" and would have to name the color corresponding with just three identically colored blocks on the tray. One day, Pepperberg asked him, "What color three?" "Five" Alex responded.
. . Puzzled, Pepperberg went back and forth with the bird, trying to understand why he was answering with a number instead of a color. He could have been bored -- such tasks are done over and over with Alex, and after 10 or 15 trials of an experiment he might ask for grapes, bananas or toys, or simply give wrong answers to indicate he's tired of playing along, Pepperberg said.
. . "OK, smarty, what color five?" Pepperberg finally asked, knowing there weren't five objects of the same color on the tray. "None", he replied. Alex didn't come up with the word on his own. Pepperberg said he knew it in the sense of absence from a study he'd been involved in on determining differences and similarities between objects --but this use was unique.
. . To determine this use wasn't a fluke, Pepperberg mixed in questions whose answers were "none" to subsequent trials, with similar results. This initial zero-like work was published in the May 2005 issue of the Journal of Comparative Psychology.
. . A 2003 study in the journal Nature found that common marsh birds called coots can recognize and count their own eggs, even when other eggs are in the nest.
. . Black-capped chickadees were recently found to warn colleagues of danger by chirping about the size and actual threat of individual predators. The language of prairie dogs includes a word for humans.
. . Some animal intelligence is hauntingly familiar, like the male monkeys that pay to see female monkey bottoms. And studies show that monkeys, dogs and rats all know how to laugh.
. . One question that dogs animal intelligence research is whether remarkable, humanlike behaviors are innate and truly cerebral or if a creature is just parroting a trainer. "It is doubtful that Alex's achievement, or those of some other animals such as chimps, can be completely trained", Pepperberg said. "Rather, it seems likely that these skills are based on simpler cognitive abilities they need for survival, such as recognition of more versus less."
July 5, 05: Australian researchers said Tuesday they have identified a new species of dolphin living in the coastal waters of northern Australia. The Australian Snubfin Dolphin, which is related to Irrawaddy dolphins found along the coasts and major rivers of Asia and northern Australia, was formally identified as a new species thanks to genetic research carried out in California. "There are clear differences between the two populations that had not been previously recognized and these were confirmed by the studies on DNA."
July 5, 05: A track from a three-toed dinosaur thought to be about 70 million years old was discovered in Denali National Park by a University of Alaska Fairbanks student. The track from a theropod, a meat-eater, is the first dinosaur evidence found in the park, and caused its first paleontology closure.
. . Anthony Fiorillo, curator of earth sciences at the Dallas Museum of Natural History, said the importance of the find was its location in Interior Alaska, far from a coastline. An Interior dinosaur likely would experience more seasonal variation in annual climate than creatures to the north or south.
. . The track is 22 cm long and 15 wide, & looks like an oversized bird footprint. "You are looking at a very large, birdlike animal except it has teeth and a tail and instead of wings, it has arms", he said. A rough comparison, he said, would be a scaled-down Tyrannosaurus rex. The age was estimated based on fossil pollen present in the rock formation.
July 5, 05: Identical twins grow apart, genetically, as the years pass, a team of European and U.S. researchers reported. Their study of identical twins show the genetic code itself does not change, but rather chemical changes after birth alter the way the gene is expressed, a process known as epigenetics. The study can help shed light on how environment and genes interact to produce disease and ordinary differences between people.
. . They studied 80 twins from Spain, and found significant epigenetic differences in 35% of them. The younger pairs of twins were identical, while the older pairs were more likely to differ from one another. "Most importantly, we found a direct association between the remarkable epigenetic differences observed and the age of the monozygotic (identical) twins: the youngest pairs were epigenetically similar, whereas the oldest pairs were clearly distinct."
. . Psychiatric diseases such as schizophrenia and bipolar disease do not occur uniformly among identical twins. And there are often physical differences. This supports theories that environmental factors, such as smoking, diet and exercise, affect DNA directly, the researchers said. It is also possible that, just as DNA mutations occur with simple aging, the epigenetic effects on genes also "drift" with age, the researchers said.
July 5, 05: CLASSIC!! Inadvertent human selection can also cause species to evolve. Take the case of the snow lotus, a rare plant that grows only high in the Himalayas. Researchers have discovered that one species of the plant has been shrinking over time —-the one people like to pick.
. . A snow lotus species called Saussurea laniceps is used in traditional Tibetan and Chinese medicine and is increasingly sought after by tourists. The largest plants are picked, and that occurs during their only flowering period. The result is that only smaller, unpicked plants go to seed. "Selection caused by humans is a powerful force, whether conscious or unconscious, artificial or natural."
. . The heavily harvested snow lotuses have been getting shorter over the last century, while those in areas not picked have not shrunk. And, they noted, a second species, S. medusa, which is not often picked, has not been changing. In the heavily harvested areas, where only the smaller plants got to reproduce, the S. laniceps averaged 5.3 inches tall, they found. The same plants in rarely harvested areas averaged 9 inches in height.
. . "Paradoxically, with unconscious human selection, when a species possesses a certain trait that is valued by people, individuals with that trait will be preferentially harvested and this selection will leave individuals with less desirable traits."
July 5, 05: A genetic study helps confirm the theory that Polynesians, who settled islands across a vast swathe of ocean, started out in Taiwan, researchers reported. Mitochondrial DNA, which is passed along virtually unchanged from mothers to their children, provides a kind of genetic clock linking present-day Polynesians to the descendants of aboriginal residents of Taiwan.
. . Samples taken from nine indigenous Taiwanese tribes --who are different ethnically and genetically from the now-dominant Han Chinese-- show clear similarities between the Taiwan groups and ethnic Polynesians. Their findings suggest that Taiwanese aboriginal populations have been genetically isolated from mainland Chinese for between 10,000 and 20,000 years, and that the original Polynesian migrants originated from people identical to the aboriginal Taiwanese.
July 5, 05: Craig Venter --one of the scientists behind the sequencing of the human genetic code-- aims to construct a living organism from a kit of genes. It would be a biological milestone were he to succeed and would open a debate about the nature of "life". Dr Venter's company will work out the minimum number of genes a bacterium needs, synthesise the genetic material and then put it in an empty cell. Ultimately, designer bacteria could be used for industrial tasks, he claims.
. . Initially, Dr Venter plans to replace the genes in the 517-gene Mycoplasma genitalium, and then alter the bug so that it is tailor-made for certain industrial uses, such as cleaning up pollution or even removing greenhouse gasses from the atmosphere.
. . Three organizations --the Massachusetts Institute of Technology (MIT); the J Craig Venter Institute in Rockville, Maryland; and the Center for Strategic and International Studies in Washington, DC-- have just begun a 15-month study to examine the societal implications of synthetic genomics. It will explore the risks and benefits of the emerging technology, as well as possible safeguards to prevent abuse, including bioterrorism.
July 1, 05: Mlaika is a 10-year-old adolescent female African elephant living in Kenya in a group of semi-captive elephants. During the day she makes sounds you might expect. But she moonlights as a truck.
. . "When she is with the other elephants, she makes normal elephant sounds", says Stephanie Watwood of Woods Hole Oceanographic Institute. "But at night, when she is by herself, she can hear the trucks from a nearby highway and imitates their sounds." Mlaika is one of two African elephants scientists have found making strange sounds. The other one chirps.
. . It's hard to know what an elephant is thinking, and the creature's reasoning could be even simpler. "She may have been bored and it was something to do."
An Australian researcher had found the males of two seal species in Antarctica woo potential mates by singing complex melodies.
. . Tracey Rogers of Sydney's Taronga Zoo said leopard seals, which can grow up to three meters (10 foot) long and have razor-sharp rows of teeth, had a sensitive side that belied their aggressive appearance. "Lone males are like opera singers. They hang upside down underwater and gently rock back and forth, singing soulful, stylised songs which carry over long distances."
. . Rogers said the songs of leopard seal males tended to fit into two categories, either a dull repetitive grunt or a complex melody that she said rivalled the beauty of humpback whale songs and could be heard underwater for 40 kilometers. She said some amorous males sang for up to 13 hours a day in an attempt to find a mate, taking short two-minute breaks between songs.
June 29, 05: Newborn dolphins and killer whales can forego sleep for their entire first month. Hard to believe? Just ask their mothers. New research finds both species of mammals can stay active 24/7 for weeks after birth. Mom gets minimal z's, too, as you might imagine. Both mother and calf gradually get more shut-eye in subsequent months. A comprehensive study in Australia concluded that the typical baby causes between 400 and 750 hours of lost sleep for Mom and Dad in the first year.
. . For dolphins and killer whales, evolution apparently has determined that sleep must take a back seat to survival. Young cetaceans can better escape predators if alert, and their body temperatures stay higher as they wait for insulating blubber to accumulate. The lack of sleep also encourages rapid brain growth, the scientists say.
Candidates for the "earliest human":
. . 7 to 6 million years ago. Sahelanthropus tchadensis. This creature is a good candidate. But we know too little yet about the species to be certain.
. . 6 million years ago. Orrorin tugenensis. Not such a promising candidate. Perhaps an early ape. If it turns out that the creature was bipedal, then his rating goes up to 'likely early man.'
. . 5.5 to 4.5 million years ago.Ardipithecus ramidus. Fair candidate as an early man. Relatively large canine teeth, narrow molars, thin enamel. Just a few skull fragments found so far. Possibly bipedal. May have been a forest dweller. Probably ate leaves and fruit.
. . 4.2 to 3.0 million years ago. Australopithecines. This group of hominids were definitely bipedal, had small canine teeth and, therefore, were early men. The Smithsonian Institute refers to them as the first humans. We've found fossils from various species within this group —-the most famous, of course, is Lucy, a 1.1 to 1.2 meter (3.5- to 4-foot) tall woman who lived about 3.2 million years ago. Early men of Lucy's species (afarensis) had low foreheads, bony ridges over the eyes, flat noses, and no chins. Protruding jaws, large back teeth — their skulls were much like those of chimps except for the teeth.
. . 2.4 to 1.5 million years ago. Homo habilis. Bipedal and similar to the australopithecines but with smaller back teeth. Definitely an early man. Possibly able to talk, judging from a bulge (Broca's area) in the cranium (visible in only one skull) that is essential for speech. Habilis was about 4 feet (1.2 m) tall.
June 22, 05: One of the puzzling features of the human genome is that although genes are numerous, they actually form less than 5% of the DNA in a cell nucleus. The rest was thus, rather cavalierly, dubbed “junk DNA” by those who discovered it. Gradually, a role for some of this junk has emerged. In particular, parts of it regulate the activity of genes, and thus which proteins are produced and in what quantities. That has implications for what a cell does -—or, to put it another way, what type of cell it is. One of the most puzzling sorts of junk, though, is something known as a LINE-1 retrotransposon. This is junk that won't stay in one place.
. . Retrotransposons are sometimes known as "jumping genes". They pop from chromosome to chromosome with gay abandon. The assumption has been that they are genetic parasites. They resemble retroviruses, which certainly are parasites (HIV, the cause of AIDS, is a retrovirus). And the effect of a string of irrelevant LINE-1 DNA popping into the middle of a functional gene is indeed traumatic. The gene in question stops working.
. . Only 100 retrotransposons are actually able to leap around, and only ten of those leap often. By and large, the parasites have been disabled, suggesting they are such bad news that evolution has eliminated them. Dr Gage and his colleagues, however, suspect that at least some of those that have not been disabled have been allowed to live on for a purpose. Instead of being destroyed, they have been subverted --and what they have been subverted to do is to create complexity in the brain.
. . Brain formation is an incredibly wasteful process. About half of the nerve cells created in a developing brain have died by the time that brain has formed. Many researchers think that which cells live and which die is decided by a process similar to natural selection. Cells with the right properties in the right places flourish; those without wither. But natural selection requires random variation to generate the various properties. Retrotransposons could provide that variation, by affecting gene expression at random.
June 22, 05: Part of instant recognition may involve individual brain cells. Scientists are intrigued that we can quickly identify people or objects no matter what angle we view them or how they look that day. They've suspected that certain neurons are specialized to be on the lookout for a single thing in this world.
. . These experiments were part of a study to localize the seizures in eight patients with epilepsy. The subjects consented to having electrodes implanted in their brains to record the signals of individual neurons. In separate sessions, the patients were exposed to a random assortment of about 100 images, while the electrodes monitored the activity of around 50 neurons in the medial temporal lobe, a small region of the brain associated with memory.
June 23, 05: When the little black-capped songbird whistles "chick-a-dee-dee", it can warn flock mates to watch out: A predator is near. Scientists had already described their call as one of the most complex in the animal kingdom. Templeton and colleagues recorded the chickadee songs, analyzed them by situation, studied the calls on acoustic instruments, and watched the birds react when the songs were played back. "These birds are passing on way more information than anyone ever dreamed possible, and only by carefully looking at these calls can we really appreciate how sophisticated these animals are. They change a bunch of different features about the call, subtle acoustic features, the spacing between the notes, things we can't hear."
. . One thing humans can hear is the number of "dee" notes at the end of the call. "The more they add, the more dangerous the predator", he said. The familiar "chick-a-dee" can indicate a stationary predator. Variations can convey how dangerous it is, whether it flies or is a snake or a mammal such as a ferret, and where it is, he said. "We had no idea that any animal was able to distinguish between predators that seem similar."
. . The call even differed slightly depending on whether the predator was a large great horned own or a pygmy owl. Despite their large hooked beak and big talons, the large owls are not as much of a concern because they are slow and the chickadees can outmaneuver them. The fast and maneuverable pygmy owl, however, specializes in small birds. When a pygmy owl perched nearby, Templeton recorded as many as 23 added "dee" notes to the chickadee call.
. . The "chick-a-dee" can also be a call to arms, bringing in the whole flock of birds to mob the sitting predator and drive it away. A second chickadee call, a soft, high-pitched sound like "seet", means there is a predator such as a hawk, owl or falcon flying nearby, Templeton reported. It is sort of "duck and cover" warning.
. . He noted that previous studies of the call have indicated that it can also contain information about the location of food, of individuals it spots or entire flocks it recognizes, previous studies showed.
June 23, 05: Hummingbirds hover by flapping their wings a bit like insects and a bit like other birds, and now a super-fast camera has made an image of the technique, scientists reported. A team of U.S. researchers found that hummingbirds manage to hover in air for long periods by supporting 75% of their weight during their wings' down stroke and 25% on the up stroke. Other birds support all of their weight on the down stroke for slow flight and short-term hovering, while insects produce equal amounts of lift on both the down and up strokes.
June 23, 05: One critical requirement, according to Shostak, is having enough time for life to get underway and then develop into something interesting. "Unlike Sun-like stars, which burn for 10 billion years and then die, M dwarfs live much longer -- as long as 100 billion years", he noted. "So if such stellar runts can occasionally spawn life, the majority of that life will be far older than the biology of our own planet. The most ancient, and potentially most interesting life might be found in the neighborhoods of M stars."
. . Because M stars are so dim compared to stars like the Sun, an M star's habitable zone is quite close to the star itself. Simply put, the planets around M stars need to lie in orbits that circle close to the stars if they are to have any chance for gathering enough energy to bear life. But the tight orbits that would be needed to host life around an M star come at a cost. When a planet orbits its star so closely, one side of the planet always faces the star.
. . The result? When a planet is tidally locked in orbit around its star, the temperatures on the sunny side would be scorching, while the dark side would be a frozen wasteland. "On the star-facing side, you pump a lot of energy in and heat up the atmospheric gas, and in the shadow on the other side it's dark and cold", said Tarter. As a consequence, the difference in temperatures whips up "enormous wind velocities." Or so scientists have thought until recently.
. . But those ideas may all change. "New models indicate that perhaps you can, with greenhouse gases, get a less dramatic energy distribution—that you can in fact circulate the energy that's being put in on one side from the star without totally tearing apart the atmosphere."
June 22, 05: Scientists have discovered the first organism known to rely on photosynthesis in a place where the sun never shines. The creature lives well more than a mile under the sea and captures dim radiation coming from hydrothermal vents.
. . Visible light is just one aspect of the electromagnetic spectrum, which includes radio waves, infrared "heat", and X-rays. Instead of sunlight, the deep-sea microbes use geothermal radiation.
We have a common ancestor with the mouse 100 million years ago.
June 19, 05: Bluetear has been breeding different kinds of animals, starting with dogs, since 1980. Roughly three years ago, she discovered a litter of smaller than normal kittens she calls "miniature cats." She now has plans to market the miniature cats, which grow to about 4 pounds, on the Internet.
June 19, 05: Japanese scientists said today that DNA tests have shown that the prehistoric woolly mammoth is more closely related to Asian elephants than to their African counterparts, settling a long-running debate over the lineage of the giant animals that went extinct 10,000 years ago. Asiatic elephants branched off from the same ancestor 4.8 million years ago. African elephants diverged from the family tree earlier on, about 7.3 million years ago, the group said.
Microraptor has two complete sets of wings, one above his chest and one below. Why? "We don’t know yet. But we’re trying to test him in a wind tunnel to see if there’s some aerodynamic advantage to it."
June 15, 05: Although the basic hardwiring of the brain is the same, there are variances in shape and organization that make even the brains of identical twins look different. How much of this is due to environmental factors or genetic pre-programming has never been fully worked out. But scientists have now found a connection between the variety in the brain's neurons and certain genes that can change their position in the genetic code. These so-called "jumping genes" may gently scramble the blueprints for the brain. "This mobility adds an element of variety and flexibility to neurons in a real Darwinian sense of randomness and selection", said Fred Gage from the Salk Institute.
. . Jumping genes, also called transposons or mobile elements, are found in all living things. Approximately 20% of the genetic code in mammals is of the jumping variety. But only a small fraction of these are "active" --which means they are able to successfully reinsert themselves into a new spot in the code.
. . The fact that jumping is not easy to do is probably a good thing. Active jumping genes have been observed in sperm and egg cells --possibly providing a small kick to evolution by instilling tiny alterations to the genetic make-up of the next generation.
. . What the scientists found is that L1 elements made hops in neuronal precursor cells (NPCs), which are cells that are destined to become neurons. This is the first time these jumps had been observed in cells other than sperm and egg cells.
. . But exactly how much of this shuffling goes on in human brains has yet to be studied. They point out that if jumping is entirely random, the L1 elements may rarely land inside a relevant gene. There is some evidence, however, that the jumping genes actually target places in the code where they can make a difference.
. . Evolutionarily speaking, one might wonder how this remarkable hopping came into existence. In most cases, a genetic mutation that provides a survival advantage eventually becomes incorporated in a population. But these gene-altering jumps only affect how one brain develops and cannot be passed on to the next generation.
. . A possible answer to this Darwinian riddle is that there could be a definite advantage to a population in having programmed variability in the thinking caps of its members. "If diversity was important, then the mechanism for creating diversity could be passed on."
June 14, 05: Researchers at Washington University have discovered that rattlers are adaptable and have some interesting habits. For example, they swim and climb trees. Some males go more than 10kms a year to look for mates. One snake caught rainwater in its funnel-shaped coil and drank from its own cup! [Does that qualify as using a tool?!]
. . There were 1,245 rattlesnake bites, with only one death, reported to the American Association of Poison Control Centers in 2003. That compares to the 44 people killed by lightning in 2003.
June 11, 05: Researchers in Germany have found that variations in a gene related to male sex hormones may be at the root of male-pattern baldness, the most common form of hair loss. The culprit is the androgen receptor gene, and it dwells on the X chromosome, which all men inherit from their mothers.
. . Experts have long believed that hair loss in inherited. But the new research, to be published in the American Journal of Human Genetics, is the first to identify a specific gene that may be involved. Other, yet-unidentified genes are likely involved in male-pattern baldness, possibly including ones handed down by fathers. But the new findings highlight the importance of mom's side of the family when it comes to a man's hairline.
. . The androgen receptor gene helps govern the workings of male sex hormones (androgens), such as testosterone. Though these hormones promote the growth of body and facial hair, on the scalp excess androgens may cause hair loss. It's possible, according to Nothen and his colleagues, that the suspect gene variant creates a greater number of androgen receptors in the scalp --and therefore stronger androgen activity.
. . The researchers say they are continuing to hunt down the other genes involved in early-onset male-pattern baldness. Scientists hope that getting at the genetic roots of hair loss will eventually spawn better baldness treatments or a cure.
June 10, 05: The National Academies, the flagship of U.S. science, said it had set up a Web site to battle attempts to portray evolution as mere speculation about how life developed on Earth. The Web site, http:/nationalacademies.org/evolution/ , carries links to various reports on evolution, which some U.S. religious groups want to be taught in schools only if their own views of a divine creator get equal credence.
June 10, 05: For years, scientists have observed loads of life at the bottom of the ocean. But they weren't able to find enough food to support all that life. Now, scientists have discovered giant sinking mucus "houses" that double the amount of food on the sea floor. The mucus houses, or "sinkers", are produced by tadpole-like animals not much bigger than your index finger. As sinkers drop to the sea floor, small sea critters and other food particles get stuck to the mucus and end up on the bottom of the ocean.
. . The animals responsible for making sinkers are called giant larvaceans. They spin a mucus web, about a yard in diameter. They sit in the middle of the house and use it to filter food that is small enough for them to eat. "Larger particles get stuck to the outside of these filters, and after some amount of time, the filters get plugged and the animal moves out", Sherlock said. "The house deflates and begins to sink, picking up more particles. It's a fast-sinking carbon bomb."
June 10, 05: Imagine a device that would let you "talk" with your dog or cat. One that could help you ask a cow a question or converse with a dolphin. Two Arizona scientists say computers may someday bridge the language gap between humans and other animals.
. . It may all start with a furry rodent in the Arizona desert. Slobodchikoff studies prairie dogs, and he says he has found that the Gunnison's variety has a remarkably complex language system. A Gunnison's prairie dog can describe and warn others of an approaching coyote or a red-tailed hawk, and do it by "name." There are consistent chirps that denote the presence of humans and even non-predators like skunks or badgers. There are specific calls for cows, elk, prong-horned antelope and domestic cats, and these calls are consistent across prairie dog colonies.
. . "Functionally, (the calls are) the same thing as words." Slobodchikoff has identified more than 20 prairie dog "words" and says he has found prairie dog calls that describe shapes and colors. "We set up some experiments where we had humans wearing different-colored shirts," he explains. "We had these people walk through prairie dog colonies, recorded the calls and found that, sure enough, there was variation that was consistent." The prairie dogs across the board had the same distinctive calls for blue shirts, green shirts, yellow shirts and so on.
. . This complexity and the apparent prairie dog use of adjectives has led Slobodchikoff to take a leap. He believes that the animals may have more than just a series of identification calls --possibly a crude language structure that may include a sort of prairie dog grammar. The scientists believe that they can find the equivalents of vowels and consonants within the alarm calls and thus learn how the calls are structured.
June 9, 05: New research reveals how carpenter ants screen nest-mates from non-mates with special chemical sensors on their antennae. ike many social animals, ants rely on chemical communication to direct cooperation, as well as identify intruders. On their bodies' thin outer lining (the cuticle), ants wear a chemical "ID badge" made up of a unique blend of compounds called cuticular hydrocarbons, or CHCs. The non-mate blends elicited aggressive behavior, which included "biting, jumping and spraying formic acid" at the surrogate ant, Ozaki said.
. . Ozaki's team determined that the intruder detector was in the ants' antennae. Specifically, non-mate CHC blends excite a certain type of small hair-like structures on the antennae called sensilla. The enemy-recognizing sensilla are relatively thick --20 microns long and 4 microns wide-- and are full of small pores. Multiple pores are often associated with an insect's sense of smell, but the researchers suspect that the ants need to rub their antennae over another ant to tell whether it is an adversary or not. "The CHCs are not volatile at ordinary temperature. Thus, I believe that the sensilla rely on contact."
. . Interestingly, the sensilla are not stimulated by the CHC blend from nest-mates. Therefore, discrimination of friend or foe may not require any processing by the ant brain - the antennae may do all the work by only sending out an alert when foreign chemistry is detected.
June 8, 05: Geckos that forego sex and instead clone themselves are able to run farther and faster than relatives that reproduce the more conventional way. "This is extraordinary", said Kellar Autumn from Lewis & Clark College in Oregon. "The traditional theory is that when a species gives up sex and reproduces through cloning, the offspring will have reduced performance." Parthenogenetic animals, which create exact copies of themselves, are all females: mothers cloning daughters. Autumn and colleagues studied the parthogenetic Bynoe's gecko from Australia.
. . The Bynoe's geckos turned out to be much better athletes than their sexually reproductive relatives, outperforming them by 50% on the treadmill. This was a surprise, since a similar study of lizards from the deserts of the United States had shown the opposite trend.
. . One of Autumn's coauthors, Michael Kearney, said that some parthogenetic species, like the Bynoe's gecko, evolved when two species crossed, or hybridized. Kearney compared these ultra-fit geckos to the "super tough" mule, which is a cross between a horse and a donkey.
June 7, 05: Scientists have unraveled snippets of the genetic code of an extinct bear species, proving a technique that could one day give a glimpse into the behavior of Neandertals. Generally speaking, the fossil record is mostly bones and teeth. But bits of DNA –-the blueprints of life-– sometimes cling to these dry specimens. If the genetic material can be extracted, it can offer a wealth of information about a long-dead creature. Scientists and science fiction writers have long dreamed of using ancient DNA to resurrect dinosaurs or wholly mammoths. The new study, proving the concept works, also shows it would be very difficult to employ on more ancient creatures.
. . Edward Rubin of the Department of Energy’s Joint Genome Institute and his colleagues were able to sequence, or decode, a small percentage of the genome from the Pleistocene cave bear, Ursus spelaeus. "We could have gotten the whole bear genome –we had enough bear DNA." The cave bears, closely related to modern brown bears, disappeared more than 10,000 years ago. Cave-paintings and fossil evidence suggest that ancient humans had contact with these animals.
. . Rubin’s team analyzed 40,000-year-old cave bear bones and teeth, collected from two caves in Austria. The relatively cold, dry conditions were optimal for DNA survival. The scientists identified about 27,000 base pairs in the bear’s DNA code --which, in its entirety, is somewhere around 3 billion base pairs long. But sequencing the entire code would have been very time-consuming. The scientists consider this bear study merely a proof of principle, as they are more interested in exploring human ancestors.
. . "The next thing is Neandertal", Rubin said. This stocky hominid species is believed to have gone extinct around 25,000 years ago. Having a full or partial Neandertal genome could tell us things that bones cannot – like what they ate, how their brain was built, or whether they spoke language, Rubin said.
. . Cousins? The extraction technique might also be used on the 18,000-year-old remains of the recently discovered Flores Man, nicknamed "the hobbit." However, the diminutive skeletons were found in a tropical environment, which likely accelerated the DNA degradation process.
. . Besides the fact that DNA falls apart over time, gene sequencing from fossils is hard to do because the DNA that is found is mostly from corpse-eating organisms. "When we die, we are a nutrient source for microbes and bugs", Rubin said. To get around this contamination, past studies have focused on DNA from mitochondria. Mitochondria are the energy suppliers in cells, but they also carry their own separate DNA for reproduction. Because there are often thousands of mitochondria in a cell, researchers have had better luck isolating mitochondrial DNA from fossils.
Bears and dogs have similar DNA –-having diverged about 50 million years ago.
June 6, 05: Female bottlenose dolphins are taught by their mothers to use marine sponges to look for food, according to a new study. The finding represents the first case of material culture observed in a marine mammal species.
. . Biologists observing the dolphins in eastern Shark Bay saw the animals break marine sponges off the seafloor and wear them over their snouts to probe into the seafloor for fish. Sponging was mostly confined to females --only one out of the 13 regular spongers was male.
. . "It looks like the animals use the sponge as a kind of glove to probe the [sediments]. It might just give them protection against some noxious critters hiding in there." "It's really hard to make genetic arguments for recent switches in behavior, because things don't happen that quickly in populations."
. . A paper published in Nature last year suggested female chimps learn from their mothers how to gather termites much faster than males --who prefer to spend more of their time playing. Dr Krützen added: "Those who work on these animals know that if there is a prime candidate for socially transmitted behavior --culture-- in the marine mammal world, it is bottlenose dolphins."
June 2, 05: Researchers have sequenced the DNA of two extinct cave bears and say their method is accurate enough to try doing it on extinct humans such as Neandertals. The cave bears are the first extinct animals to have their genes sequenced, and the findings can be used to determine the precise relationship between the 40,000-year-old bears and living species. "We picked cave bear as an initial test case ancient DNA target because the samples we used in the study are roughly the same age as Neandertals."
. . Genetics experts need nuclear DNA --the kind that is mixed together and passed along from both parents-- to get a real idea of a creature's genetic heritage. To do this, the international team of researchers turned to cave bear remains.
. . "When people hear about our success, they immediately think about how this strategy could work for dinosaurs." While experts have found some soft tissue in 70-million-year-old dinosaur fossils, it is not at all clear whether any measurable DNA remains.
. . Rubin said it may also be possible to extract DNA from the remains found in Indonesia of the Flores Man, a small Homo erectus nicknamed "the hobbit" because of its tiny stature. These remains have been dated to just 18,000 years ago.
June 2, 05: A Tyrannosaurus rex dinosaur that died 68 million years ago has provided some of the strongest evidence yet that birds are the closest-living relatives of dinosaurs, scientists said.
. . Soft tissue found in the animal's thighbone strongly suggests it was a female, and just about to lay eggs. The bone tissue is strongly similar to that made inside the bones of female birds --and no other living type of animal-- when they are producing the hard shells of eggs just before they lay them. It indicates that dinosaurs produced and shelled their eggs much more like modern birds than like modern crocodiles."
. . Female birds produce a layer of bone tissue called medullary bone when they are laying eggs. It is rich in calcium, providing minerals that would otherwise be leached from harder bone material, leaving the bird susceptible to fractures. "The way that crocodiles lay and shell their eggs is they hold them in their reproductive tract and shell them all at once. Birds shell their eggs one at a time as they move down through the reproductive tract. It is a pretty calcium-intensive process."
. . Finding medullary bone is a long shot, she said. First it has to be an ovulating female, then it has to die before it has finished laying eggs, then it has to be fossilized and finally that fossil has to be found by humans. The fossil is between 68 million and 67 million years old, Horner said.
. . This particular T. rex fossil made headlines in March when the same team of paleontologists reported it contained preserved soft tissue --the first ever found in a dinosaur bone. "It was so far out in the country that we needed to helicopter it out and we actually had to split the thighbone into two pieces to get it into the helicopter." When Schweitzer unwrapped the cracked-open femur she immediately saw the soft tissue and went to work proving its remarkable state of preservation.
. . Horner plans to crack open some other bones.
. . The researchers said the medullary bone in the dinosaurs was more like that found in ostriches and emus than that of smaller birds. "Anyone who would argue that birds and dinosaurs are not related --frankly I'd put them in the Flat Earth Society group", said Jack Horner of the Museum of the Rockies and Montana State University.
June 2, 05: The first known North American skulls of Cretaceous era sauropods —-big dinosaurs with little heads-— have been uncovered in recent years by Brigham Young University and Dinosaur National Monument researchers. The new sauropod, which has not yet been formally named, may have been 25 feet long with an 18-inch skull.
About a dozen sauropod skulls are known from the earlier Jurassic era, but these are the first in North America for the Cretaceous, the final 80 million years of the dinosaur period.
. . All four are the same type, a new species and genera, Chure said. They lived around 100 million years ago, or possibly a little earlier.
June 1, 05: Scientists said the discovery of a short-necked dinosaur from the Late Jurassic period has turned accepted ideas around: that the long-necks ruled the roost. The skeleton of the dinosaur --which was less than 10 meters long-- discovered in Patagonia goes against the grain of increased body size and neck length that typified sauropod dinosaurs.
. . "The long neck is a particular hallmark of sauropod dinosaurs and is usually regarded as a key feeding adaptation." The researchers said they believed the short-necked dinosaurs of southern Latin America --whose closest known relatives are to be found in Africa-- may have evolved to deal with specific feeding requirements. "The tendency toward neck shortening in dicraeosaurids indicated that these ... were progressively adapting for low browsing and might have been specialized on specific food sources."
June 1, 05: The largest marsupial that ever lived was even bigger than we thought, Australian scientists say. New info on the immense wombat-like Diprotodon optatum indicates it reached more than two and a half tons on average --nearly double some previous estimates. This makes the creature heavier than the largest rhinoceros. Only elephants among living terrestrial mammals can claim to be more massive. With its gigantic bulk, D. optatum would also have been a mighty handful to hunt, suggesting that rapid overkill by humans was probably not the main cause behind its extinction more than 30,000 years ago.
. . It nurtured young in a pouch like modern-day wombats and kangaroos.
May 31, 05:
It is unlikely humans exterminated the immense marsupial Diprotodon and other huge beasts that once roamed Australia in a short killing spree. Two new studies reject the theory that humans moving on to the continent more than 45,000 years ago took out its megafauna in a 1,000-year "blitzkrieg". The studies suggest instead a more complex pattern to the extinctions.
. . Their authors say humans certainly had a role but it was not as important as the period's climate changes. In North America, for example, the demise of mammoths and sabre-toothed tigers at the end of the Pleistocene Epoch is coincident with the arrival on the landmass of humans with new stone-spear technologies about 12,000 years ago. And in Australia, the extinction of great beasts --such as the marsupial lion (Thylacoleo carnifex), the immense wombat-like Diprotodon optatum and the 400kg lizard Megalania prisca-- also occurred at roughly the same time humans appeared on the scene.
. . They report detailed new dating data on fossils found in New South Wales. These suggest humans lived side by side with the great beasts of Australia for at least 10-12,000 years. "There is not a single stone-spearpoint in Australia until, at the very earliest, about 15,000 years ago - long after anyone thinks the megafauna went extinct." "You try taking out a two-to-three-ton wombat with a pointy stick. I don't doubt the first Aboriginals did hunt megafauna but the argument that they did it with the efficiency required to effect near-instantaneous extinction is not, in my view, credible." He says that the colder, drier climate that came about between 50,000 and 20,000 years ago changed the type of animals that could survive in the region of Australia that he studied.
. . Some commentators in the Australian media questioned whether Trueman's and colleagues' dating was as reliable as they claimed. They also pointed to evidence that the megafauna had withstood previous climate uphevals, making it unlikely that one more extreme, Late-Pleistocene shift would have had such a big impact on its own.
May 27, 05: A new study confirms Bee dancing is a form of communication. Bees outfitted with tracking devices responded to the wiggling of one of their fellow foragers, who had just returned to the hive from some newfound bee vittles. The dance, which is performed on one of the honeycomb walls, is not an exact language, but it gets the job done.
. . The central element of the choreography is a shimmy, or waggle, along a straight line. For emphasis, the bee repeats this move several times by circling around in a figure-8 pattern. The angle that the shimmy makes in relation to an imaginary vertical line is the direction to the food source with respect to the sun. For example, a waggle dance pointing towards 3 o'clock is bee talk for: "Hey, there's food 90 degrees to the right of the Sun." It was noticed that the number of waggles in one figure-8 corresponds to the distance to the meal.
. . Some scientists have speculated that the waggle dance merely excites other bees, which then fly out of the hive searching for a scent trail left by the returning bee.
. . To solve the controversy, Riley and colleagues strapped radar transponders to 19 dance spectators. The flight paths show that the bees make a beeline to the vicinity of the food source, but then fly around in a looping search pattern. Only two of the radar-tracked recruits actually found the food.
. . Apparently, the dance gives incomplete instructions, and the bees rely on odors, colors, and other clues to hone in on the final location. Still, the dance gets them pretty close. On average, the recruits came within 18 feet of the food before switching to search mode.
May 26, 05: Flowers make people happy. And while that might seem obvious, there hasn't been much research to prove the point until now. A trio of new studies by Rutgers University scientists supports the notion pretty strongly, and the experts go on to speculate that flowers have flourished on this planet, with their beauty evolving in recent millennia, partly because humans are so attached to them.
. . The first study involved 147 women. All those who got flowers smiled. Make a note: all of them. That's the kind of statistical significance scientists love. Among the women who got candles, 23 percent didn't smile. And 10 percent of those who got fruit didn't smile.
. . Another: In an elevator, 122 men and women were given either a flower, a pen, or nothing. Those who got flowers smiled more, talked more, and --here it gets interesting-- stood closer together.
. . Finally, in another test, bouquets were delivered by florists to 113 men and women in a retirement community. All 113 got flowers and a notebook, but some got them earlier and received a second bouquet when the others got theirs. By now you can guess the outcome. The more flowers, the more smiles.
. . From there, it's a bit of a leap to the idea that flowers are prolific because we love them. But the results got the scientists to thinking about how the flower industry of today has evolved into growing things that serve no other purpose than emotional satisfaction. Nature won't even pollinate many of the domesticated flowers. Just among roses, there are so many types conjured by humans that, clearly, flowers aren't what they used to be. But it's likely our collective hand has played a role longer than you might think.
. . Rutgers geneticist Terry McGuire suggests that nature's prettier flowers got to survive and thrive because people didn't destroy them when they cleared land for agriculture. Instead, they cultivated them and have been doing so for more than 5,000 years.
. . "Our hypothesis is that flowers are exploiting an emotional niche. They make us happy", McGuire says. "Because they are a source of pleasure - a positive emotion inducer - we take care of them. In that sense, they're like dogs. They are the pets of the plant world. As humans moved into agricultural settings, these flowers would have been weeds. They might have been tolerated because of their beauty. The seeds would have been preserved --perhaps initially because they were mixed with crop seeds-- and replanted. Humans would have become the seed dispersers. Over time, the best of these flowers might have been selected and the seeds more carefully preserved."
May 25, 05: Scientists exploring an emerging undersea volcano near the islands of American Samoa in the South Pacific were so amazed to find eels living in the newly formed lava that they nicknamed the population "Eel City."
. . Hundreds and perhaps thousands of purplish-gray eels about a foot long were swimming around and hiding in the nooks and crevices at the summit of the new volcano at a depth of about 600 meters, Craig Young, director of the University of Oregon's Oregon Institute of Marine Biology, said. "We were astounded", said Young. "Many of us had worked on hydrothermal vents in other parts of the ocean and had never seen or heard of anything like this before." [The species has not yet been determined --perhaps a new one.]
DEVOLUTION --by H. ALLEN ORR
Why intelligent design isn't.
. . Issue of 2005-05-30
http://www.newyorker.com/fact/content/articles/050530fa_fact
May 20, 05: Less than 50km from San Francisco, an archipelago of rocky islands rises out of the Pacific Ocean, forming a largely undisturbed wildlife haven that biologists call California's Galapagos.
. . The public isn't allowed onto the granite islands that make up the Farallon National Wildlife Refuge —-the country's largest seabird breeding colony outside Alaska and Hawaii. But on a rare visit organized by the U.S. Fish and Wildlife Service, several journalists saw an ecosystem teeming with life. Only a handful of bird researchers and maintenance workers are permitted to set foot on the 211-acre archipelago at any given time, although that could change. Starting next week, the Fish and Wildlife Service will begin seeking public comment on a 15-year conservation plan that will address public access, among other issues. The agency is considering allowing small groups of naturalists to visit, but probably not tourists.
Once devastated by hunting and a long military presence, wildlife has rebounded on the Farallones. The four main islands and dozens of craggy outcroppings are home to five species of marine mammals and 12 species of seabirds, totaling 300,000 or 30 percent of California's breeding seabirds.
. . The islands, which can be seen from San Francisco on clear days [the Oakland hills, too], aren't exactly conducive to visitors. Because of stormy seas and steep dropoffs into the ocean, there are no docks. After a rocky 2 1/2-hour boat ride from San Francisco, authorized visitors must approach the main island in a small raft, then get hoisted onto the island by a 10meter crane.
. . Visitors are greeted by a deafening chorus of shrieking gulls —-so loud that some researchers wear earplugs. A hike to the solar-powered lighthouse on the 100meter peak of Southeast Farallon Island offers stunning views of the archipelago.
May 19, 05: A spider relative called a harvestman trapped in amber could shed light on how arachnids were affected by the extinction that wiped out dinosaurs. The 100-million-year-old arachnid, which looks like it might have died last year, wandered though a dinosaur-dominated world. Harvestmen are small arachnids with very long, thin legs and a small body.
. . Though older fossils exist, hardly any are known from the Mesozoic Era (245 million-65 million years ago). One of the reasons this specimen is causing excitement is that it might help tackle the question of how many arachnid groups managed to survive the great extinction of around 65m years ago. "Overall, the arachnids seem to have sailed through."
. . Unlike true spiders, which are predators, harvestmen have broader tastes. They eat vegetable matter, and dead insects. The harvestman hit on a successful evolutionary "design" fairly early on and has changed rather little over the past few hundred million years.
May 19, 05: Two separate teams of researchers working hundreds of miles apart have discovered a new species of monkey in Tanzania. The highland mangabey is the first new species of monkey identified in 20 years and conservationists immediately said the find showed how important it was to preserve African forests. It will likely be classified as a critically endangered species.
May 19, 05: A new analysis of Australia's oldest human remains suggests humans arrived on the continent about 50,000 years ago. The evidence is based on a re-examination of the so-called Mungo Man skeleton. The data will come as a relief to palaeontologists who support the "Out of Africa" theory. Some had suggested the skeleton was 60,000 years old, challenging the popular idea that all people alive today are descended from a group that arose in Africa some 100,000 years ago.
May 19, 05: The evolutionary path that separated humans from chimps 5 million years ago may have made human sperm survive better but paradoxically may have made humans prone to cancer. A comparison of chimpanzee genes to human genes shows a concentration of genes unique to people in areas associated with sperm production and cancer, and suggests the changes that make humans unique also make us uniquely prone to cancer.
. . In cancer, cells lose their ability to self-destruct when they become faulty, a process called apoptosis. Cell cycling --the process by which cells activate, divide, and grow into two separate cells-- is also disrupted in cancer. Apoptosis also kills many developing sperm cells before they mature. But evolution could have interfered with this process, allowing more sperm to reach maturity, thus carrying the mutation into the next generation. Cancer in people usually occurs in late adulthood, after they have reproduced, and thus has not been removed by natural selection --the process that leads to evolution.
. . Clark said chimpanzees get cancer, too, but no one has been able to study enough of them in captivity to see if they do so at the same rate and in the same ways as humans do.
May 17, 05: Bees across the US have succumbed in recent years to a treacherous alien mite that invaded the country two decades ago. But scientists haven't been able to figure out why the parasite is so destructive. Up to 60% of hives in some regions have been wiped out. Entire colonies can collapse within two weeks of being infested. North Carolina fears it is on the verge of an agricultural crisis. No state is immune. As much as a third of the American diet depends on their ability to pollinate crops that total in the billions of dollars every year.
. . A new study suggests the killing mechanism is complex. The mites not only eat bees from the inside out, but they suppress the bee's immune systems. That opens the door for a virus that deforms bee wings to take over. The entire hive, even its food source, gets infected.
. . The bees' nemesis, the eight-legged Varroa destructor mite, is the size of a pin head. It gets inside the bees' airways, begins feasting and blocks breathing. It also eats bee larvae. The mites are resistant to pesticides. Breeding programs designed to develop bees that can resist the mite have so far been unsuccessful.
. . Researchers suspect the mite arrived on Chinese honeybees around 1987. The Chinese bees know how to deal with the parasite. Chinese honeybees have grooming behavior which can remove the mites from the bees. They get rid of the mites."
. . Some researchers have advocated fostering dwindling populations of wild native honeybees --some 4,000 species are native to North America. While most seem to resist the mite, they're numbers have shrunk due to pesticide use and changes to the land. Wild bees often nest in the ground and can't survive in an agricultural setting.
May 17, 05: Scientists sometimes gravitate to the strange even when simpler explanations are available. Take the Stegosaurus, for example, whose spiky outfit was thought by some to be a defensive array. The plates that lined the backs of this oddly adorned dinosaur may have had no other function than to help them identify each other, like the colorful feathers on birds, scientists said today.
. . Stegosaurs lived during the Jurassic period, about 210 to 144 million years ago. The most recognizable species, Stegosaurus stenops, was 7M long and had rows of plates down its back. Other stegosaurs had spikes instead of plates, or a combination of the two.
. . A team of paleontologists has analyzed plates from the fossil record, ruling out some of the previous explanations given for this distinctive feature. The bony plates, called scutes, had been thought to protect these herbivores from attacks from predators like the ravenous Allosaurus, but the fin-shaped appendages apparently would not have been strong enough for the job. Not that dinosaurs couldn't make protective gear. The ankylosaurs had club-like tails that were light and strong as a surfboard or bulletproof vest, a recent study found.
. . Another theory had the plates acting as heat exchangers, like the ears of an elephant. On hot days their large surface area could have radiated heat away to cool the beast. This hypothesis was justified by the existence of large blood vessels that left tracks through the bone. But the new study found that the blood vessels were all dead ends, which argues against thermoregulation.
. . Large vessels are common in the horns and antlers of many living animals. These skull appendages are not meant for heat exchange --the big "pipes" instead supply the blood needed for fast growth. This may be the reason for stegosaurus' large vessels, as well.
. . The researchers argue that stegosaur plates served no other purpose than to tell species apart. Other peculiar dinosaur adornments --like the horns of triceratops, the domes of the pachycephalosaurs, and the crests of the duck-billed hadrosaurs - may also fall into this category of mere decoration.
May 15, 05: Young canaries happily learn songs that sound nothing like their species, but they revert to a strict canary-like melody as they mature, Science reports.
. . A US team was surprised to find it could teach juvenile birds a haphazard jumble of computer generated tunes. However, the birds' impressive flexibility gave way to rigid rules when breeding became a priority. As soon as the canaries received a pubescent surge of testosterone, they dropped all the incorrect lessons they had learned and started singing traditional canary songs. Even canaries that did not get to imitate any songs at all developed the proper tune as adults.
. . Counter-intuitively, although they spend a long time laboring over new songs, listening carefully, imitating and perfecting, young canaries do not actually seem to need it. Once adult, they can sing just fine without it. The real test, according to Professor Gardner, would be whether or not females chose them as mates over birds that grew up with more conventional lessons.
May 13, 05: The first humans who left Africa to populate the world headed south along the coast of the Indian Ocean. Scientists had always thought the exodus from Africa around 70,000 years ago took place along a northern route into Europe and Asia. But according to a genetic study, early modern humans followed the beach, possibly lured by a seafood diet. They quickly reached Australia but took much longer to settle in Europe. The new research suggests they moved along the coasts of the Arabian peninsula into India, Indonesia and Australia about 65,000 years ago. An offshoot later led to the settlement of the Middle East and Asia about 30 to 40,000 years ago.
. . When the first modern humans evolved in Africa, they lived mainly on meat hunted from animals. But by 70,000 years ago, they had switched to a marine diet, largely shellfish.
. . The data comes from studies by two teams of scientists on the DNA of native people.
May 12, 05: Jake Socha of the University of Chicago has been studying snakes' ability to act like birds for eight years.
. . "First of all, they flatten their bodies out all the way from their head to tail. Snakes are part body and part tail, and they have ribs up until the tail. They flatten their ribs and make themselves Frisbee-like in form." This gets them aerodynamically fit for gliding. "As [the snake] starts falling, it starts sending large S-shaped waves through its body mostly by moving its head from side to side", Socha explained. "It also keeps its body parallel to the ground."
. . Since they don't have wings, snakes control their flight patterns by sort of slithering through the air. By undulating their bodies in an exaggerated S-shaped pattern, they maintain in-flight stability. It's sort of like how a tight-rope walker shifts weight from side to side to keep balance.
. . Socha isn't quite sure why snakes developed the ability to glide, but he suggests that they do it to save energy. "Say you're in one tree and you want to get to another tree that's 50 feet away. You would have to climb down, slither across, and climb up the tree."
. . Most flying snakes --there are three additional species-- grow about 3 to 4 feet long. They secrete a mild venom, but this is only hazardous to small prey --such as lizards, birds, frogs, and bats-- and they are officially classified as harmless to humans.
May 11, 05: In a rare addition to the animal family tree, scientists have discovered a new family of rodent. It looks like a squirrel, sort of. But you can see rat-like features in its face. And in some ways it more closely resembles the guinea pig or chinchilla. While new to science, the critter is well known in Southeast Asia. It has long whiskers and stubby legs, with a tail covered in dense hair. It prefers limestone outcrops and forests. The researchers think it is a vegetarian. Interestingly, it gives birth to one offspring at a time, rather than a litter. Bone fragments of the newfound rodent were dug out of an owl pellet, so it has at least one wily predator.
. . DNA analysis and a comparison of the skull and other bones to other creatures suggest Kha-Nyou [Thai name] diverged from other rodents millions of years ago.
May 11, 05: A tiny Canadian shrub is the quickest-moving thing in the plant world, using a catapult mechanism to eject its pollen at a speed hundreds of times faster than a launched rocket, scientists have found. The plant, bunchberry dogwood, grows in thick carpets in the vast swampy, spruce-fir forests of the North American taiga. Growing to a height of only 20 cm, the bunchberry needs the explosive push to get its pollen into the forest breeze so that it maximises its chance of fertilizing other shrubs. It does so by using its star-shaped flower like a trebuchet --a giant medieval catapult that had a wooden throwing arm with a strap attached to its tip.
. . The whole process takes 0.5 milliseconds --half a thousandth of a second-- from start to finish and is the fastest movement ever recorded in a plant. During the first 0.3 milliseconds, the bunchberry stamens accelerate at up to 2,400 G, or about 800 times the forces that astronauts experience during takeoff.
. . Another possibility may come from insects. A relatively large insect, such as a bumblebee, could trigger the flower opening, and pollen could stick to its hairs, thus enabling cross-pollination when the creature visits other plants.
May 10, 05: A rare species of tree dating back millions of years has been planted at Kew's Royal Botanical Gardens by wildlife expert Sir David Attenborough. The Wollemi pine, once thought to have been extinct for 200 million years, was recently discovered in Australia, sparking a major conservation project. Fewer than 100 adult trees are known to exist in the wild, and the exact location of Wollemi groves remain a secret. It is thought the pines populated the ancient supercontinent Gondwana when dinosaurs walked the Earth.
. . A tall conifer, it is closely related to the monkey puzzle tree, and has an unusual pattern of branching, with the mature foliage having two ranks of leaves along the branches.
May 10, 05: A tiny coral reef-dwelling fish called the pygmy goby has taken the record as the shortest-lived vertebrate. The pygmy goby lives an average of 59 days. The fish lives fast and dies young.
. . A team from James Cook University in Australia reports that the tiny coral reef goby lives a frantic existence to avoid becoming extinct. The tiny size of the coral reef pygmy goby limits the number of eggs a female can produce. She can lay a maximum of three clutches --about 400 eggs in total. The males stay guard and fan the eggs to provide them with more oxygen.
Our bodies are still wired for hunter-gatherer biology —-and that's a dangerous configuration for a society with all-you-can-eat buffets.
May 8, 05: If the red-eyed tree frog embryo waits too long to hatch during its roughly one-week incubation period, it might become a meal instead. But nature has given this frog the clever ability to recognize vibrations created in a snake attack and hatch a few days early in order to escape, a new study found.
. . The embryos huddle in gelatinous blobs, clinging to tree leaves that hang over watery locations in Panama. When snakes find them, they start munching. If you're not among the first embryos in a blob to be eaten, you have some time to get away. After the initial bite, the embryos start to wiggle frantically, the study found. They rupture their egg capsules and drop into the water. Now called tadpoles, they swim to safety. The embryos can hatch up to three days sooner than normal when attacked.
. . Lots of things can shake an egg blob, though. Like a heavy rain. It seems the embryos pay attention not to the speed of the vibrations or their force, but rather to a characteristic amount of time between movements that indicates a predator is in their midst.
May 7, 05: The prevailing view of early Earth is that it was utter hell, a fiery environment unsuitable for life. Scientist even named it the Hadean eon, for the ancient Greek word for the down under. But the planet may have been suitable for life just 200 million years after the solar system formed, new research suggests.
. . This new view "contrasts with the hot, violent environment envisioned for our young planet by most researchers and opens up the possibility that life got a very early foothold", Bruce Watson of Rensselaer Polytechnic Institute said.
. . "Our data support recent theories that Earth began a pattern of crust formation, erosion, and sediment recycling as early in its evolution as 4.35 billion years ago." The planet would still have been quite hot, and the atmosphere would have consisted only of carbon dioxide, water, and volcanic gases. But life may still have been able to exist in these types of conditions. "Previously, the widely accepted idea has been that 'impact sterilization' prevented life from getting a foothold until much later.
. . Watson and his colleague, Mark Harrison of Australian National University, developed a technique for looking at zircon crystals to determine the temperature and possible environmental conditions of early Earth. "Zircon allows us to go further back in geologic time because they survive processes that rocks do not", said Watson. The zircon crystals they studied predate the world's oldest rocks by 400 million years. "Although they measure only a fraction of a millimeter in size, zircons hold a wealth of information about the very earliest history of Earth."
. . They measured the titanium content of the crystals from the Jack Hills area of Western Australia. From this data, they could determine the zircon's crystallization temperature. The temperature data they uncovered supports the existence of a wet Earth within 200 million years of the solar system's formation.
May 4, 05: Fossils of an ancient fish --dating back 450 million years, when the creatures had neither bones nor teeth-- have been found in South Africa. The finds, which are 50 million years older than any other fossil fish in Africa, will help provide a "missing link" in the evolution of early fish.
. . "People may wonder how we know these fossils are fishes, when we have no bones with which to identify them. The answer is that the exceptional preservation displayed in these rocks enables us to recognize the eyes, scales and even the liver of the animals. The impressions in the shale are faint, but they are also clear and diagnostic."
. . The animals lived in a time when Africa was in an ice age, and before any animals had colonised the land. According to the team, they lived in a shallow sea fed by melt waters from receding ice-sheets.
. . Although the researchers are still in the early stages of analyzing the fossils, they think the fish might have been swimming scavengers. "They had no teeth, so they might not have been predators."
. . They're not the oldest fossil fish ever to be found. The fossil of a fish which lived about 530 million years ago in China was found in the late '90s.
May 5, 05: A slimy lungless salamander closely related to an America variety has been found a long way from home --in the woods of South Korea, but scientists said they don't know how it got there. The nocturnal creature was named Karsenia koreana but will be commonly known as the Korean crevice salamander and is significantly different from other lungless salamanders.
. . The lungless salamander, which breathes through moist skin and lays its eggs on land, is typically found in North and South America and has some distant relatives in Italy and Sardinia. But scientists had never expected to find one in Korea because it split from its aquatic cousins, which are common there, at least 175 million years ago.
. . From early observations, the salamander looked so familiar that scientists believed it to be an American transplant. The outward appearance of the salamander is superficially similar, Wake said. After closely inspecting its DNA and anatomy, it became clear that this species was distinctly different. Wake estimates that it diverged from American species 60 million years ago.
. . In ancient times, a land bridge up to 1,000 miles wide made the Bering Strait walkable. Exactly why most salamanders became extinct in Asia still stumps scientists. Wake suggests that there may have been a drying phase in Southern Asia, which could have ruined their habitats.
May 4, 05: Twenty-three years ago, an American philosophy professor named James Flynn discovered a remarkable trend: Average IQ scores in every industrialized country on the planet had been increasing steadily for decades. Despite concerns about the dumbing-down of society --the failing schools, the garbage on TV, the decline of reading-- the overall population was getting smarter. And the climb has continued, with more recent studies showing that the rate of IQ increase is accelerating. Next to global warming and Moore's law, the so-called Flynn effect may be the most revealing line on the increasingly crowded chart of modern life --and it's an especially hopeful one. We still have plenty of problems to solve, but at least there's one consolation: Our brains are getting better at problem-solving.
. . Every decade or so, the testing companies would generate new tests and re-normalize them so that the average score was 100. To make sure that the new exams were in sync with previous ones, they'd have a batch of students take both tests. They were simply trying to confirm that someone who tested above average on the new version would perform above average on the old, and in fact the results confirmed that correlation. But the data also brought to light another pattern, one that the testing companies ignored. "Every time kids took the new and the old tests, they did better on the old ones", Flynn says. "I thought: That's weird."
. . Flynn dug up every study that had ever been done in the US where the same subjects took a new and an old version of an IQ test. "And lo and behold, when you examined that huge collection of data, it revealed a 14-point gain between 1932 and 1978." According to Flynn's numbers, if someone testing in the top 18 percent the year FDR was elected were to time-travel to the middle of the Carter administration, he would score at the 50th percentile.
. . The trend Flynn discovered in the mid-'80s has been investigated extensively, and there's little doubt he's right. In fact, the Flynn effect is accelerating. US test takers gained 17 IQ points between 1947 and 2001. The annual gain from 1947 through 1972 was 0.31 IQ point, but by the '90s it had crept up to 0.36.
. . Though the Flynn effect is now widely accepted, its existence has in turn raised new questions. The most fundamental: Why are measures of intelligence going up? The phenomenon would seem to make no sense in light of the evidence that g is largely an inherited trait. We're certainly not evolving that quickly.
. . Dickens and Flynn showed that the environment could affect heritable traits like IQ, but one mystery remained: What part of our allegedly dumbed-down environment is making us smarter? It's not schools, since the tests that measure education-driven skills haven't shown the same steady gains. It's not nutrition - general improvement in diet leveled off in most industrialized countries shortly after World War II, just as the Flynn effect was accelerating.
. . Most cognitive scholars remain genuinely perplexed. Harvard's Steven Pinker: "I suspect that it's either practice at taking tests or perhaps a large number of disparate factors that add up to the linear trend."
Over the last 50 years, we've had to cope with an explosion of media, technologies, and interfaces, from the TV clicker to the World Wide Web. And every new form of visual media - interactive visual media in particular - poses an implicit challenge to our brains: We have to work through the logic of the new interface, follow clues, sense relationships. Perhaps unsurprisingly, these are the very skills that the Ravens tests measure --you survey a field of visual icons and look for unusual patterns. The best example of brain-boosting media may be videogames.
The ultimate test of the "cognitively demanding leisure" hypothesis may come in the next few years, as the generation raised on hypertext and massively complex game worlds starts taking adult IQ tests. This is a generation of kids who, in many cases, learned to puzzle through the visual patterns of graphic interfaces before they learned to read.
May 4, 05: The monarch butterfly is known to use the angle of sunlight as a navigational guide on its annual fall migration from across North America to Mexico. But how it processes the information has been a mystery. Now scientists have used a flight simulator and peeked inside the butterfly brain to learn that their light-detecting sensors are hard-wired to their circadian clocks, allowing the creatures to compensate for the time of day.
. . Monarchs are very adept at sensing ultraviolet light, a wavelength of sunlight that is invisible to the human eye and causes skin cancer. The butterflies can detect the sun's angle even on a cloudy day, allowing them to always head South. Scientists have known this for years.
. . Researchers led by Steven Reppert of University of Massachusetts Medical School found evidence last year that the butterflies rely on polarized ultraviolet light. Polarized light has been filtered to vibrate in one plane instead of all directions. In sunglasses, polarization reduced glare.
. . In the new work, Reppert and his colleagues discovered that ultraviolet photoreceptors dominate the part of the monarch eye that specializes in polarized light detection.
May 4, 05: Birdlike dinosaurs newly unearthed in Utah may be a "missing link" between primitive meat-eating creatures and more evolved vegetarians, U.S. researchers reported. The 125-million-year-old fossils show features of two-legged carnivorous dinosaurs called maniraptorans, from which birds are believed to have evolved. The fossils also have leaf-shaped teeth, stubby legs and the expansive bellies of plant-eaters.
. . "Falcarius is literally a missing link", Scott Sampson, chief curator at the Utah Museum of Natural History, told a news conference. "Falcarius is kind of half-raptor and half herbivore. This transition is triggered by a shift in diet." It appeared at around the time that tasty, nutritious, flowering plants appeared on Earth, he said. "We know that the first dinosaur was a small-bodied, lightly built, fleet-footed predator", Sampson added. All other dinosaurs evolved from it. However, as with many radiations of major groups of animals, it happened so quickly that we really don't have much in the way of fossil documentation." Falcarius provides part of the picture, he said.
. . The adult Falcarius would have walked on two legs and was about 13 feet long and 4.5 feet tall. It had strong forearms, sharp, curved, 4-inch (10 centimeter) claws and a long neck. It probably had feathers and is the earliest North American example of a therizinosaur, a group that includes feathered dinosaurs found in southeast China and maniraptorans, including the Velociraptor, perhaps best known from the novel and film "Jurassic Park."
. . "Falcarius shows the beginning of features we associate with plant-eating dinosaurs, including a reduction in size of meat-cutting teeth to leaf-shredding teeth, the expansion of the gut to a size needed to ferment plants, and the early stages of changing the legs so they could carry a bulky body instead of running fast after prey."
. . "Hundreds, perhaps even thousands" of individual fossils were found. Kirkland believes the animals perhaps lived in flocks or herds, were attracted to plants around the spring and occasionally poisoned en masse by gas or contaminated water.
May 3, 05: The Malagasy people of Madagascar carry the genes from ancestors in both nearby East Africa and also distant Borneo, suggesting a big migration from Asia back to Africa 2,000 year ago, British researchers reported. Madagascar, the largest island in the Indian Ocean, lies 250 miles off the coast of Africa and is 4,000 miles from Indonesia. Its long isolation has led to the evolution of unique animals, including lemurs, rare birds and plants.
. . The genetic study supports the puzzling finding that the Malagasy language more closely resembles Indonesian dialects than east African tongues but does little to answer the question of how the settlers arrived.
. . A team of genetics experts at the universities of Cambridge, Oxford and Leicester looked at both the Y chromosomes of Madagascar residents, inherited virtually unchanged from father to son, and the mitochondrial DNA, passed directly from mothers to their children. Tiny mutations in these two forms of DNA provide a kind of genetic clock that can help scientists trace human migration and inheritance.
. . "Malagasy peoples are a roughly 50:50 mix of two ancestral groups: Indonesians and East Africans.
May 2, 05: Eighty years after a famed courtroom battle in Tennessee pitted religious beliefs about the origins of life against the theories of British scientist Charles Darwin, Kansas is holding its own hearings on what school children should be taught about how life on Earth began.
. . The Kansas Board of Education [-Avoidance] has scheduled six days of courtroom-style hearings to begin on Thursday in the capitol Topeka. More than two dozen witnesses will give testimony and be subject to cross-examination, with the majority expected to argue against teaching evolution.
. . Many prominent U.S. scientific groups have denounced the debate as founded on fallacy and have promised to boycott the hearings. "I feel like I'm in a time warp here", said Topeka attorney Pedro Irigonegaray. "To debate evolution is similar to debating whether the Earth is round. It is an absurd proposition."
. . Kansas has been grappling with the issue for years, becoming a worldwide laughingstock in 1999 when the state school board voted to downplay evolution in science classes. Subsequent elections altered the membership of the school board and led to renewed backing for evolution instruction in 2001. But elections last year gave religious conservatives a 6-4 majority and the board is now finalizing new science standards, which will guide teachers about how and what to teach students.
. . School board member Sue Gamble, who describes herself as a moderate, said she will not attend the hearings, which she calls "a farce. I think it is a desire by a minority... to establish a theocracy, both within Kansas and growing to a national level."
May 2, 05: A fossil found in South Dakota is that of a never before seen species of dinosaur, a horse-sized plant eater with spikes on its bony flat head, scientists said.
. . "When my colleagues saw a CAT scan of the new fossil, they tore up their family tree diagrams and said, 'Back to the drawing board!' ... We never suspected such a creature existed", said paleontologist Robert Bakker.
. . The nearly complete pachycephalosaur skull was donated to the museum by three amateur fossil hunters from Iowa who found it in 2003 while exploring the Hell Creek Formation in central South Dakota.
Apr 30, 05: We're not as racially pure as we think we are. An African-American, for example, on average will find that he or she has about 20% European ancestry, says Tony Frudakis, founder and chief scientific officer of DNAPrint. It costs $219 per test.
. . Last fall, Samuel Richards, who teaches a race-relations course at Penn State University, arranged for 100 of his students to take the DNA test. About 20% were "very surprised" to find out they had a mixed heritage.
. . Native Americans are believed to have immigrated from central Asia thousands of years ago. These same central Asians also migrated into eastern Europe, meaning that her "native American" DNA could have come from there, he says. Greeks and Ashkenazi Jews also may show significant percentages of "native American" ancestry for the same reason. Eventually, a more sophisticated test will be able to sort out these differences. Rather than emphasize differences, he says, "the great social function of these tests is that they absolutely drive home kinship --that [humans] are all related."
Apr 28, 05: Computer predictions can then be made that can determine the shape of the modern human vocal tract from bone data alone. The same equations can then be used with data from a Neandertal skull to predict the shape of a Neandertal vocal tract.
. . The tract seems to have been shorter and wider than a modern male human, closer to that found today in modern human females. It's possible, then, that Neandertal males had higher pitched voices than we might have expected. Together with a big chest, mouth, and huge nasal cavity, a big, harsh, high, sound might have resulted. But, crucially, the anatomy of the vocal tract is close enough to that of modern humans to indicate that anatomically there was no reason why Neandertal could not have produced the complex range of sounds needed for speech.
. . The semi-circular canals of the inner ear provide us with our sense of balance, and by studying a range of animals, Spoor, has found a high correlation between the size of the canals and agility. Throughout human evolution, our canals seem to have increased in size as our agility has increased. But Neandertals have smaller canals than modern humans, and even earlier ancestors suggesting they were less agile.
. . Returning to the skeleton, Professor Trenton Holliday found an explanation for this - that the short limbs and wide pelvis of our Neandertal would have resulted in less efficient locomotion than modern humans. The energy costs in travelling would have been higher, and this would have been a serious evolutionary disadvantage.
. . For Neandertal, it was an ironic end --the very body plan that had made Neandertal so well adapted to the ice age had locked him into an evolutionary cul-de-sac. He might have been better adapted to the cold than the first modern humans, but as the landscape changed, it was our ancestors who could take better advantage of the more open environment.
. . In an experiment, two modern humans with very different body shapes were subjected to cooling in an ice bath --one with the long limbed, athletic shape of a runner, the other with the stockier, heavily muscled body plan closer to that of a Neandertal. The heavily muscled person lasted longer in the ice bath, so Neandertals would have had an advantage. His muscle would have acted as an insulator, and his deep chest did help to keep organs warm.
. . Even so, the advantage doesn't mean that Neandertal could have survived the icy extremes --this was a polar wasteland and his heavily muscled body plan needed a lot of feeding: about twice as much as we need today. [& my conjecture: all that heavier-than water muscle, lil fat, & thick bones... meant that he couldn't swim. This limited his hunting range at the next river --or drowned him.]
April, 05: "Meat-tolerant" genes, a new study purports, allowed humans to shifted from a primarily plant-based diet to one consisting mainly of meat 2.5 million years ago.
Apr 28, 05: The ivory-billed woodpecker, feared extinct for 60 years, has been seen in a remote part of Arkansas, ornithologists said. Several experts have spotted and heard at least one and possibly more ivory-billed woodpeckers deep in an ancient cypress swamp in eastern Arkansas. The last reliable sighting: Louisiana in 1944.
. . "It is a flagship of the blunders of excess of overharvesting ... the great old forests of the southern United States."
. . They specialize in digging the bark off tall hardwoods that have died, and a breeding pair needs a large territory. The survival of ivory bills is closely tied to that of the deep, swampy forests it lived in. The Big Woods area where the sightings occurred was heavily logged in the 19th and early 20th century but many of its tall hardwoods have grown back since then.
. . The birds only live about 15 years, so the sightings mean they must be breeding somewhere.
Apr 28, 05: A parasitic bird called the Horsfield's hawk-cuckoo lays an egg in the nest of another bird species, such as the bushrobin. That's just the beginning of the treachery. When the hawk-cuckoo chick is born, it pushes the bushrobin's natural offspring out of the nest.
. . Scientists have wondered how the parasitic chick gets fed, because other studies have shown that it takes the stimulation of multiple open beaks --either the sight or the sound-- to compel a mother bushrobin to provide food.
. . The clue to the mystery is in bright yellow patches on the ends of the hawk-cuckoo's wings. Japanese researchers found that the chicks make those patches quiver, and they mimic the mouths of other chicks. So the lone nestling gets fed. The researchers tested the idea by covering the yellow patches with black paint. When they did that, the parasitic chicks got less food.
. . America's brown-headed cowbird is also a nest invader. But the cowbird joins its nestmates in a chirping chorus to bring in more food than it could on its own.
Apr 28, 05: In Barbados - It's male. But what is it? A zonkey? A deebra? That's the debate in Barbados since a zebra gave birth to a foal sired by a donkey. He was born April 21, a milk-chocolate brown creature with the black stripes of a zebra on his ears and legs. His face looks more like a horse, with a distinctive black "V" patch on the forehead.
Apr 27, 05: Millions of years ago, the oceans were ruled by a bus-sized, whale-eating shark with teeth as big as your hand. Scientists have long believed that the prehistoric megalodon shark evolved into today's scariest sea predator, the great white. However, a new study comparing teeth suggests that the great white is more closely related to the smaller, but equally vicious mako shark.
. . Ciampaglio digitized hundreds of teeth --upper, lower, front, and back teeth from the three species, and analyzed their sizes and shapes. The analysis showed great whites and makos have very similar tooth and root structure. They also have very similar growth trajectories - how a tooth changes in size and shape as the shark grows to its adult size. The great white and megalodon, however, shared none of these characteristics. The megalodon was probably the end of a run of giant sharks that died out 2-3 million years ago, he said.
. . Recently, a few fossil species was found off South America that look like an intermediate between the great white and mako.
Apr 27, 05: The critically endangered kakapo --fat, green, musty-smelling nocturnal parrots, which cannot fly but can climb tall trees-- are confined to New Zealand's offshore islands. Kakapo (Strigops habroptilus) numbers dwindled to just 51 in the mid-1990s, but an intensive conservation effort has boosted their numbers. This year, on the predator-free Codfish Island/Whenua Hou, off the bottom tip of New Zealand, a team of volunteers and Department of Conservation (DOC) staff have watched over five new chicks.
A research team found that dogs and humans are more like each other genetically than either is to a mouse. The study suggests that dogs have at least 18,500 genes in common with a total of some 25,000 human genes so far identified.
When similar sequences are believed to be related to each other by evolutionary descent they are said to be homologous. Paralogous genes is the term used for genes possessed by an individual which are related by duplication and divergence.
. . Pseudogenes without introns may result from incorporation of processed RNA messages back into genomic DNA by reverse transcription. Shuffling and reuse of exons appears to occur. The whole picture is therefore one of very considerable complexity.
. . Orthologous genes is the term used for genes shared by two individuals which are related by divergence following reproductive isolation.
Nylon wasn't invented until 1937. When scientists found a new species of bacteria feasting on nylon byproducts, they became quite interested. When they compared old and new strains, they found the new strain must have nylon byproducts to live, and that its novel nylon-digesting abilities were due to a frame shift mutation in one gene. In a frame shift, a mutation of just one nucleotide can push the whole sequence by a notch, creating a brand-new protein. In this case, the protein reacted to nylon products, and suddenly gave the bacteria a whole new niche. The novel proteins we see in real life do indeed appear to be due to inherited changes in DNA, just as evolution demands.
Meat-tolerant" genes, a new study purports, allowed humans to shifted from a primarily plant-based diet to one consisting mainly of meat 2.5 million years ago.
Apr 21, 05: A unique fly from the Canary Islands has helped shed light on one driving force behind the birth of new species. The robber fly is found nowhere else, and scientists speculate that the rich biodiversity on the islands may actually have led to its emergence. The researchers think sharing an island with a myriad of other lifeforms may push one species to evolve into another. This new theory adds fresh insight into how biodiversity arises. "Why some areas contain greater species diversity than others has been a fundamental question in evolutionary ecology and conservation biology."
. . It is thought "speciation" --the evolution of a new species-- can occur when two populations of the same species become isolated, allowing them to "grow apart" genetically over the course of many generations. Eventually, the two populations become so different that if they were to meet again they would no longer be able to breed, meaning they had become separate species.
. . One species can also evolve into another if strong selective forces are placed upon it (where certain genes or genetic traits are favoured by natural selection), or if its population is small enough to allow for "genetic drift", which happens when certain traits are lost --or become proportionately more common-- simply because the gene pool has shrunk.
. . But exactly what drives speciation is still not fully understood by scientists, and it is an area of intense research. By carefully studying animals and plants in the Canary and Hawaiian Islands, Dr Emerson and his colleague Niclas Kolm were able to show an apparent link between biodiversity and the evolution of new species.
. . They found that endemic species, such as the predatory robber fly (Promachus vexator), are more common in places that are bustling with many different species. Therefore, they speculate, new species are more likely to evolve if they are surrounded by an already rich biodiversity. "Imagine you have an island colonized 100 species and a similar island colonised by 10 species", explained Dr Emerson. "If you leave that for a period of evolutionary time, the percentage of entirely new forms will be higher on the island with 100 species on it."
. . The researchers can think of three reasons why this might be the case. First, species that are forced to share a space with a lot of other species usually have smaller population sizes. That means they are more susceptible to genetic drift, which can speed up speciation.
. . Secondly, islands with a rich biodiversity have more habitat complexity. In other words, instead of just one habitat --say, grass-- there is, for example, grass, shrubs and trees. That means species are more likely to evolve new adaptations and, eventually, become different species.
. . Thirdly and, the researchers believe, most importantly, competition between species can encourage speciation.
Apr 20, 05: Nylon wasn't invented until 1937. When scientists found a new species of bacteria feasting on nylon byproducts, they became quite interested. When they compared old and new strains, they found the new strain must have nylon byproducts to live, and that its novel nylon-digesting abilities were due to a frame shift mutation in one gene. In a frame shift, a mutation of just one nucleotide can push the whole sequence by a notch, creating a brand-new protein. In this case, the protein reacted to nylon products, and suddenly gave the bacteria a whole new niche. The novel proteins we see in real life do indeed appear to be due to inherited changes in DNA, just as evolution demands.
Apr 20, 05: A crafty ant species builds a trap dotted with foxholes for surprise attacks on an insect. They stretch their victim out like a medieval criminal on a rack as more ants swarm in for the kill. Such incredible cooperation among ants has never before been described by scientists.
. . The ants, called Allomerus decemarticulatus, live in trees in the Amazon. Their trap is made of natural plant hairs, some regurgitated goo, and a binding fungus that the ants, amazingly, appear to farm. It allows the ants to snag a meal, such as a large flying insect, that they otherwise could not handle.
. . Here's how it works: An insect lands on the trap, which to the unsuspecting eye looks like part of the tree. Ants spring from dozens of holes in the gallery-like structure and grab the bug's legs, stretching them out to immobilize the large prey. Other worker ants swiftly arrive to sting the bug to death. Before long, the insect is carved up and carted away. "To our knowledge, the collective creation of a trap as a predatory strategy has not been described before in ants."
Apr 18, 05: An American paleontologist and a team of Egyptians have found the most nearly complete fossilized skeleton of the primitive whale Basilosaurus isis in Egypt's Western Desert, a university spokesman said. Philip Gingerich of the University of Michigan excavated the well-preserved skeleton, which is about 40 million years old, in a desert valley.
. . The skeleton, which is 50 feet long, could throw light on why there are so many fossilized remains of whales and other ancient sea animals in Wadi Hitan and possibly how the extinct animal swam.
. . Basilosaurus isis is one of the primitive whales known as archaeocetes, which evolved from land mammals and later evolved into the two types of modern whale. But it looks like a giant sea snake and the paleontologists who found the first archaeocetes thought they were reptiles.
Apr 15, 05: The only whale-dolphin mix in captivity has given birth to a playful female calf, officials at Sea Life Park Hawaii said. It's a mix of a false killer whale and an Atlantic bottlenose dolphin. Although false killer whales and Atlantic bottlenose dolphins are different species, they are classified within the same family by scientists.
Apr 14, 05: A dinosaur who died more than 65 million years ago with two eggs ready to lay shows that the animals were very bird-like, but also resembled reptiles such as crocodiles, researchers said. It would have been about 12 feet or 4 meters long.
. . While the fossil does not answer the ultimate question of whether birds descended from dinosaurs, it will help answer questions about how birds, reptiles and dinosaurs are related. Like birds, the dinosaur probably would not have been able to lay its entire clutch at once, but like a crocodile, she had two ovaries to make eggs. These dinosaurs were known to have made nests with more than a dozen eggs inside. The discovery of two mature eggs inside suggests this species made two eggs, laid them, and then repeated the process until her nest was full. Birds do this, one egg at a time. Animals such as crocodiles lay a full clutch at once. And they have leathery shells, while the shells of these dinosaur eggs were hard, like a bird's.
. . The dinosaur's egg-producing capability lay somewhere in between, suggesting a link with the modern bird, researchers said. It could produce more than one egg, but only one from each ovary at a time. "That might be related to the origin of flight", he said, explaining that maybe birds needed to lighten their body, and so developed one oviduct.
Apr 13, 05: Indigenous people around the world will be asked to supply a cheek swab to help geneticists answer the question of how humanity spread from Africa, the National Geographic Society and IBM said. They hope to sample 100,000 people or more and look for ancient clues buried in living DNA to calculate who came from where and when.
. . Fossils provide some clues about where people settled as they evolved and moved from Africa to colonize every continent except Antarctica. But mysteries remain, for example, about how people first got to Australia 50,000 to 60,000 years ago, or when and from where the first humans arrived in the Americas.
. . Experts in related fields such as population genetics, archeology, evolution science, linguistics and paleontology will help in the five-year project. Geneticists will look at little changes in DNA code that have been used by experts to trace human history. Mitochondrial DNA, handed down virtually unchanged from mothers to their children, is one source that was used to calculate the so-called ancestral Eve, who lived in Africa about 180,000 years ago.
. . Men have their own version, found in the Y chromosome, which is inherited with very little change from father to son. Tiny mistakes in the code that occur with each generation can be used as a kind of genetic clock to track backward.
Apr 12, 05: Utah State University reachers who've been following the evolutionary battle between toxic newts and the garter snakes that prey upon them have discovered the molecular basis of the snake's defense against the poison. As the garter snakes have raised their chemical defenses, the newts have become more deadly. The USU researchers found one newt carries enough neurotoxins --of the same type found in Japanese puffer fish-- to kill 50,000 mice or 10 people!
. . Another discovery was that separated populations of garter snakes differ in their amino acid sequences. In their separate habitats, at least two populations of garter snakes apparently evolved the defenses on their own. One question the team would like to answer is "How many times has this elevated level of resistance evolved?"
April?, 05: A research team found that dogs and humans are more like each other genetically than either is to a mouse. The study suggests that dogs have at least 18,500 genes in common with a total of some 25,000 human genes so far identified.
When similar sequences are believed to be related to each other by evolutionary descent they are said to be homologous. Paralogous genes is the term used for genes possessed by an individual which are related by duplication and divergence.
. . Pseudogenes without introns may result from incorporation of processed RNA messages back into genomic DNA by reverse transcription. Shuffling and reuse of exons appears to occur. The whole picture is therefore one of very considerable complexity.
. . Orthologous genes is the term used for genes shared by two individuals which are related by divergence following reproductive isolation.
April 8, 05: A team of Japanese genetic scientists aims to bring woolly mammoths back to life and create a Jurassic Park-style refuge for resurrected species. They aim to revive the Ice Age plant-eaters, 10,000 years after they went extinct. Their plan: to retrieve sperm from a mammoth frozen in tundra, use it to impregnate an elephant, and then raise the offspring in a safari park in the Siberian wild. "If we create a mammoth, we will know much more about these animals, their history, and why they went extinct."
. . Many mammoth experts scoff at the idea, calling it scientifically impossible. "DNA preserved in ancient tissues is fragmented into thousands of tiny pieces nowhere near sufficiently preserved to drive the development of a baby mammoth", said Adrian Lister, a paleontologist.
. . Mammoths first appeared in Africa about four million years ago, then migrated north and dispersed widely across Europe and Asia. At first a fairly generalized elephant species, mammoths evolved into several specialized species adapted to their environments. The hardy woolly mammoths, for instance, thrived in the cold of Ice Age Siberia. In carvings and cave paintings, Ice Age humans immortalized the giant beasts, which stood about 3.4 meters tall at the shoulder and weighed about seven tons. At the end of the last ice age, about 10,000 years ago, woolly mammoths dwindled to extinction as warming weather diminished their food sources, most scientists believe.
. . There are believed to be ten million mammoths buried in permanently frozen soil in Siberia. Because of the sparse human population in the region, though, only about a hundred specimens have been discovered, including two dozen complete skeletons. Only a handful of complete carcasses have been found.
By repeating the procedure with offspring, scientists say, they could produce a creature that is 88 percent mammoth within 50 years.
. . In 1986, Iritani's lab successfully fertilized rabbit eggs artificially, employing a technique now used in humans. In 1990 his colleague Goto, the Mammoth Creation Project head scientist, pioneered a breeding plan to save a native Japanese cow species by injecting dead sperm cells into mature eggs.
. . The current challenge is finding viable woolly mammoth DNA. The DNA in mammoth remains found to date has been unusable, damaged by time and climate changes. Current Siberian permafrost temperatures are minus 12 to 8 degrees Celsius (10 to 18 degrees F), which may not be cold enough for DNA survival. Sperm is not the only possible DNA source, and mammoth-elephant crossbreeding isn't the only potential way to resurrect the woolly mammoth. An alternative method would be to clone a mammoth from DNA found in mammoth muscles or skin. To do this, however, scientists would need preserved cells with some unbroken strands of DNA.
. . His team has already picked out a home for living mammoths in northern Siberia. The preserve, dubbed Pleistocene Park, could feature not only mammoths, but also extinct species of deer, woolly rhinoceroses, and even saber-toothed cats, he said.
Apr 8, 05: Lop off a newt's leg or tail, and it will grow a new one. The creature's cells can regenerate thanks to built-in time machines that revert cells to early versions of themselves in a process called dedifferentiation. Researchers who study this mechanism hope one day to learn how to induce the same "cell time travel" in humans. If the cells go back far enough, they become stem cells.
. . Tsilfidis and her colleagues are now trying to pinpoint which genes are responsible for kick-starting newt dedifferentiation. They published findings identifying 59 DNA fragments that seem to play a role in newt forelimb regeneration, and Tsilfidis believes many of those gene fragments have counterparts in humans.
Apr 8, 05: A new study of tropical reef fish calls into question a modern theory for how species develop and supports Darwin's original idea of ecology as the driving force of speciation.
. . Natural selection by itself can cause an advantageous gene --say a longer neck on a giraffe-- to spread among interbreeding organisms. But in order for evolution to explain the emergence of two distinct species, some sort of "wedge" needs to exist that drives populations apart.
. . Darwin thought that the distinct survival pressures in different habitats were enough to cause new species to form. But in 1942, Ernst Mayr developed a theory that populations had to be isolated geographically - such as by a mountain range or a glacier - in order to form separate gene pools, where random genetic mutations would generate divergent species.
. . But Rocha and his colleagues at the Smithsonian Tropical Research Institute have found that genetic differences in wrasses, a type of fish living in coral reefs, are best explained by the unique selection mechanisms of particular habitats, as opposed to some kind of physical barrier.
. . Wrasses, in particular, spend 30 days in a free-floating larval stage, which allows them to spread over a large region. However, where the Amazon River dumps into the Atlantic, the amount of sediment and freshwater is too much for coral reefs to form and fish larvae can't easily spread across this 1,200-mile gap. Rocha's team decided to look at wrasses on both sides of this apparent barrier. "Since all of these species have similar abilities to disperse, I expected to find genetic differences that corresponded to the barrier in all of them, but, surprisingly, that wasn't the case."
. . The DNA of wrasses living in different habitats separated by just 200 miles were more distinct than the DNA from wrasses with similar habitat-preference living more than 2,000 miles apart across the Amazon barrier. Some of the wrasse species are specialists --they do best in a particular coral reef habitat. According to Rocha, the larvae of a specialist will easily travel 200 miles and wind up in a different habitat, but because of natural selection, "they will lose out to the locals."
. . He thinks, in the end, a more comprehensive theory of speciation will be a mixture of both geographic and ecological speciation.
Apr 6, 05: Is a fossil creature that grabbed headlines three years ago really the earliest known ancestor of modern humans? Or does it belong elsewhere on the evolutionary tree? The answer has been hotly debated, but now two studies argue that it does indeed belong on the human branch. It dates to about the time where, according to genetic data, the ancestors of humans and the ancestors of chimpanzees went their separate evolutionary ways. It also suggests that hominids evolved quickly from apes after they set off on their own evolutionary path.
. . New evidence shows a 7 million year-old skull unearthed in Chad is the earliest member of the human family. It was hailed as arguably the most important fossil discovery in living memory because it was thought to be an ancient ancestor of modern humans. Some scientists argued it was a fossil of a female ape, but newly found remains of tooth and jaw fragments and a computer reconstruction of the skull, reported in the science journal Nature, suggest Toumai was more human than ape. The find has a puzzling combination of modern and primitive features. It had an ape-like brain size and skull shape, combined with a more human-like face and teeth.
. . They also believe the skull reconstruction suggests that Toumai (the name given to children in Chad born close to the dry season) might have been able to walk upright, which would mean bipedalism was present in the earliest known hominids. Bipedalism is a crucial difference between apes and humans. The position of the hole where the spinal cord enters is like what's seen in humans but not apes, which suggests upright walking, they wrote.
. . In a separate report, Ponce de Leon and their colleagues said newly found dental and jaw fossils from the same time as Toumai also show differences between it and African apes.
early Apr, 05: A huge cosmic explosion could have caused a mass extinction on Earth 450 million years ago, according to an analysis by scientists in the US. A gamma ray burst could have caused the Ordovician extinction, killing 60% of marine invertebrates at a time when life was largely confined to the sea.
. . These cosmic blasts are the most powerful explosions in the Universe. The scientists think a 10-second burst near Earth could deplete up to half of the planet's ozone layer. With the ozone layer devastated, the Sun's ultraviolet radiation could have killed off much of the life on land and near the surface of oceans and lakes.
. . "A gamma ray burst originating within 6,000 light-years from Earth would have a devastating effect on life. We don't know exactly when one came, but we're rather sure it did come --and left its mark. What's most surprising is that just a 10-second burst can cause years of devastating ozone damage."
Apr 5, 05: According to researchers at MIT, a single gene and its growth-promoting protein (CPG15) may be used to develop therapies for renewing damaged or diseased brain tissue. Over-expressing CPG-15 in rats gives them bigger brains; these enlarged brains have grooves and furrows like evolved mammalian brains with larger surface areas.
. . In another recent study at Harvard, the beta-catenin gene in selected mice was engineered to exhibit increased activity; the mouse brains grew to almost double the usual size. The cerebral cortex, seat of intelligence and language, became more human like.
Apr 5, 05: An international team of researchers will study social interaction at the Great Ape Trust of Iowa this spring to learn more about human forgiveness and the process of culture. "By looking at how apes learn to channel certain abilities such as forgiveness, our understanding of these processes becomes infinitely deeper", she said. "We cannot gain this depth of understanding by only looking at humans because we are too close to these processes in ourselves to objectify them."
. . Savage-Rumbaugh said many people believe forgiveness is a concept which only applies to humans. The research center's hypothesis is that it is not a process of species, and that like other social behaviors, "forgiveness is a set of patterned interactions that can be imparted to a group by how its newest members are treated."
Apr 4, 05: The marsupial "lion", cousin of the kangaroo & one the greatest carnivores to roam Australia, had the most powerful bite of any mammal species --living or extinct. The assessment comes from scientists who have compared the heads of all manner of beasts, from dogs to bears. It became extinct more than 40,000 years ago.
. . The "lion" also had a huge "thumb claw" to grapple with and disembowel its victims.
. . The data show --as one might expect-- the carnivores with the biggest bite forces are typically the ones that take larger prey relative to themselves. "Marsupials for any given size had a much bigger bite than placentals", explained Dr Wroe. "A 30kg Tasmanian tiger was biting much harder than a 30kg grey wolf and the marsupial lion, which on average was about 100kg, had a bite fore comparable to that of a 250kg African lion. It seems conceivable, Wroe and colleagues believe, that the skull architecture required for these bigger brains has evolved at the expense of muscle potential. But what the placentals lack in biting power, they compensate for in their smarter attack strategies. "The cross-sectional area available for the two major muscle jaw-closing systems may be inversely proportional to the size of the brain.
. . And this hypothesis takes an interesting turn with saber-toothed cats. The data shows them to have had relatively small bites for their size. Modern lions or tigers today have similar bite forces and are substantially smaller animals. But who needs to bite hard when your giant, 15cm-long canines will punch deep into a victim's neck and bring about rapid bleeding and death?
. . If you plot brain size versus body size, there is a nice regular relationship --except for humans --we are way off the scale.
Apr 1, 05: While giant dinosaurs roamed the planet 150 million years ago, a tiny mammal scurried about, living on a diet of termites and other insects. Scientists found the fossilized remains of the chipmunk-sized mammal at the Late Jurassic Morrison Formation in Colorado. The animal had hollow teeth without enamel and forelimbs that were designed for digging, much like today's aardvarks, anteaters and armadillos. Since that method of eating doesn't require much chewing, the teeth developed into hollow structures lacking the hard enamel coating that helps provide a good chewing surface.
Apr 1, 05: Studies by various groups suggest monkeys, dogs and even rats love a good laugh. People, meanwhile, have been laughing since before they could talk. "Indeed, neural circuits for laughter exist in very ancient regions of the brain, and ancestral forms of play and laughter existed in other animals eons before we humans came along with our 'ha-ha-has' and verbal repartee", says Jaak Panksepp, a neuroscientist at Bowling Green State University.
. . When chimps play and chase each other, they pant in a manner that is strikingly like human laughter, Panksepp writes in the April 1 issue of the journal Science. Dogs have a similar response.
. . Rats chirp while they play, again in a way that resembles our giggles. Panksepp found in a previous study that when rats are playfully tickled, they chirp and bond socially with their human tickler. And they seem to like it, seeking to be tickled more. Apparently joyful rats also preferred to hang out with other chirpers.
. . Panksepp speculates it might even lead to the development of treatments for laughter's dark side: depression.
Apr 1, 05: When attacked, slugs squirt an inky cloud into the face of their attacker. While this behavior is old hat to scientists, it wasn't until recently that they knew just how the ink did the trick. This is not exactly pen ink. A variety of chemicals make up the defensive secretion, creating a multi-pronged attack. The ink targets the predator's nervous system and messes with the creature's behavioral control system.
. . Yet there's a lure, too: The ink packs a few chemicals that the lobster can't resist. The slug squirts out an amino acid called taurine, which smells so tasty that the lobster drops the slug. The other things kick in and lobster starts acting wacky and confused, giving the slug time to make an escape. It's like a toddler dropping the broccoli when he gets a whiff of chocolate-chip cookies.
The slug buys even more getaway time by making its ink extra sticky - it goops up the lobster's antennae. Not only does this distract the lobster as it tries to clean itself off, but the ink's neurological effects are longer lasting.
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