Geologic Time Mesozoic and Cenozoic

Mesozoic Era 248-65 mya “middle animals” Great changes in animal life: reptilian forms dominant Great changes in land plant life: gymnosperms become dominant, then angiosperms develop

Triassic period 248-206 mya Follows devastating extinction Marine biosphere: molluscs, fish and corals dominant, along with marine reptiles Land: reptiles radiate to pterosaurs and dinosaurs

Triassic Tectonics Pangaea begins to break apart into Gondwana and Laurasia Arid climate Far north and south have swampy conditions

Triassic Land Life Stagonolepis: armored thecodont Cycad: gymnosperm Pisanosaurus: ornithischian dinosaur Tree fern Exaeretodon: cynodont

Triassic Marine Life Ichthyosaurs dominant reptiles Cephalopods recover in oceans Small patches of coral reef Fish of uniform variety, may indicate that Permian extinction affected them greatly

Jurassic Period 206-144 mya Land: lush plant growth, large herbivorous dinosaurs Marine: fish, cephalopods, ichthyosaurs, plesiosaurs

Jurassic Land Life Sauropod dinosaurs Large forests First birds Early mammals

Cretaceous Period 144-65 mya Breakup of Pangaea continued, massive volcanic eruptions Climate begins to cool Ended in mass extinction

Cretaceous Land Life Dinosaurs very diverse Mammals, birds Angiosperms begin to spread

Cenozoic Era 65 mya to present Australia pulled away from Gondwana Antarctica moved over South Pole India moved north and collided with Asia

Cenozoic Era Period of long-term cooling w/ a high temperature blip (PETM) Antarctic Circumpolar current Isthmus of Panama strengthened Gulf Stream and Humbolt Current

Cenozoic Era Land: Age of grasses, mammals, birds Marine: fishes and gastropods common