1. Adapted from Tim Stuckey July 17, 2006
Mesozoic Life

3. But first: Ediacaran Fauna
Ediacaran Fauna refer to sessile (non-moving) organisms
~ mya
Represented a diverse collection of ‘weird’ soft-bodied organisms that fossilized under seemingly unlikely conditions.
Probable cause of extinction: changing environment, advent of predators
PROBLEM: Ediacaran Fauna don’t seem to fit in the evolutionary tree of life and experience preservation bias (soft bodies tend NOT to fossilize and are underrepresented).

5. Paleozoic

6. Mesozoic Era 66-250 million years ago “age of dinosaurs”
It just wasn’t meant to be! (the breakup of Pangea-----Gondwana and Laurasia go their separate ways)
Appearance of Birds and Mammals
Marine Life also rapidly changing

7. Pangaea

9. Life After the Permian Extinction
Mesozoic seas dominated by mollusks, sea urchins, crustaceans, fish, and marine reptiles.
Sponges and corals were still present
Corals belonged to Scleractinia (the living group of corals)
Crustaceans were new

10. Marine Life
Mollusks recovered from the Permian extinction much better than brachiopods.
Most successful clams and gastropods were good burrowers (to escape the new crustacean predators, and ammonites with much stronger jaws)
Several planktonic groups appeared (such as diatoms)

11. Ammonite
Mollusk
Brachiopods
Diatoms

12. Larger Marine Life
Cephalopods (bilateral symmetry; Octopi) were very common
Bony fish developed hundreds of species
Marine reptiles were also present; reptiles with fins (plesiosaurs, elasmosaurus); marine reptiles resembling dolphins (ichthyosaurs)

14. Dinosaurs
The two major groups of dinosaurs emerged in the late Triassic (saurischians and ornithischians)
Saurischians are large dinosaurs
Ornithischians differed in pelvis structure from the saurischians. But don’t let the prefix fool you, very few of them flew!

15. Saurischians
T-Rex Archaeopteryx Sauropods

16. Ornithischians
Stegosaurs Iguanodonts Pterosaurs

19. Early Mammals Mammals appeared during the Mesozoic, but were small
Placental mammals and marsupials both were well established by the end of the Mesozoic, ready to take over the world after the great extinction!

20. Kaboom! The Mesozoic ended with a bang, around 66 million years ago
Possibly caused by a large meteorite striking the Yucatan Peninsula
Possibly caused by large volcanoes
Possibly caused by major regression of seas
Possibly caused by disease.
Possibly caused by…..