Life in The Oceans
The modern fauna were new marine organisms whch filled the habitat in the oceans which included crabs,lobsters,clams,snails,sponges,sea urchins. The major marine vertrbrate groups include bony fishes,sharks,aquatic reptiles,and aquatic mammals.
Important Index Fossils
Ammonites are related to modern nautiluses,
octopuses,and squids.Their abundance proves that they were successful predators.Swimming reptiles
ruled the Mesozoic oceans.Ichthyosaurs resembled
dolphins while plaesiosaurs resembled walruses and seals.
Life on the Land
The large,temperate coal swamps dried up,and the climate gradually warmed. Flies,mosquitos,wasps,
and bees, were not as common inMesozoic rocks.
Angiosperms Evolve
angiosperms are seed bearing plants that have flowers.Before the Cretacious, there were no flowers.
Early Mammals
Small,primitive mammals evolved during the late Triassic. Mammals can be identified in fossils by the srtucture of the lower jaw,middle ear,and teeth.
Flying Reptiles
Pretosaurs were flying reptiles that dominated the air during the Mesozoic. Crocodiles and turtles also arose during the Mesozoic and still exist today.
Dinosaurs Rule The Land
Dinosaurs came in all sizes,from very small to
extraordinarily large,and all were terrestrial.Two major groups of dinosaurs are recognized based on their hip structure:Ornthischia and Saurichia.
Ornthischia means "bird hipped" and Suarichia means "lizard hipped".
Warm-Blooded and Cold-Blooded
All living reptiles are cold-blooded animals,or ectotherms,meaning that their body temperatures vary in response to outside temperatures.All living birds and mammals are endotherms,meaning that they maintain relatively constant body temperatures.
Section 24.1 Mesozoc Paleogeography
The Breakup of Pangea- An important event that occured during
the Mesozoic Era was the breakup of Pangea
Cordillera-Geologists refer to the mountain ranges that formed during the Mesozoic and the Middle Triassic.
Paleogeography
The Ice Ages
As Australia splt apart from Antarctica durng the Mddle-to-Late Eocene,the warm climate began to deteriorate.A change in ocean circulation is thought to be the cause.
Continental Collisions
Before Africa collided with Eurasia a narrow sea called the Tethys Sea seperated the two continents.The collision between Africa and Eurasia continues today.India traveled north and collided with the southern margin of AsiaThe force of this tremendous continent-to-continent collision resulted in the formation of the Himalayan Mountains,which contain the point of highest elevation on Earth,
Mt. Everast.
Section 24.4 Cenozoic Life
Life on Land
Forests dominated North America during the Paleocene and Eocene.As the climated cooled the forests gave way to open land.Grasses,which were important to many large mamamals,appeared during the Eocene.The grasslands supported a large diversity of mammals,including dogs,cats,rodents,rabbits,camels,horses,pronghorn antelope,and mastodons.
Plestocene Mammals
When the Pliocene ice age began the savannas were replaced by more arid land.A new group of animals evolved to populated the land including the wooly mammoth,dire wolf,and the sabre-toothed cat.
Primates
Are distinguished from other mammals by a grasping hand with an opposable thumb and two eyes directed forwardthat result in stereoscopc vision.Our species,Homo Sapiens,belongs to a group of primates called hominids.
The Rise of Homo Sapiens
Neanderthals had hevy brows,mouths that projected forward,and receding chins.They had muscular bodies,lived in caves and had a variety of tools that they used.
click here for pictures of the LeBrea Tar Pitts
click here for pictures of Dinosaurs