1. Permian Most notable event of the Permian is the mass extinction event at the end of the Permian This event was the largest mass extinction in earth’s history 90% of marine species and 70% of terrestrial vertebrates went extinct in just 1- 8 million years

2. Permian mass extinction Trilobites Rugosan corals

3. Causes of the Permian mass extinction No one is sure. Three hypotheses have been proposed: Asteroid impact Terrestrial volcanism Stagnant seas degassing carbon dioxide

4. Cotylosaur Stem Reptiles

5. Therapsida Mammal-like Reptiles

6. Thecodontia

7. Pterosauria

8. Hadrosaurs (ornithiscians)

10. Fig. 20.03

11. Theropod dinosaur

12. Deinonychus (theropod)

13. Plesiosaurs

14. Ichthyosaurs

15. Icthyosaurs

18. Fig. 20.04b

19. Cretaceous plants Arrival of the angiosperms changed earth fundamentally During the early Cretaceous, gymnosperms were dominant The angiosperms appeared in the late Cretacous - 100-110 mybp

20. Angiosperm radiation By the end of the Cretaceous, 50 of the 500 modern families had arisen

21. Cretaceous insect radiation New groups evolved including the moths, butterflies, ants and bees Are these evolutionary arrivals unrelated to the radiation of angiosperms? I think not! These insects fed on nectar from the flowers Coevolved system - the insects relied on the plants for nectar and the plants relied on the insects for pollination

22. Fig. 20.06

23. Chicxulub crater Chicxulub crater on Mexico's Yucatan Peninsula 125 miles across Many paleontologists believe this crater is the site of the bolide impact that caused the K/T mass extinction Iridium signature around world

24. Mammals - victors by default Mesozoic were midnight ramblers Mesozoic mammals were poor competitors with dinosaurs Radiation of mammals occurred only after the demise of the dinosaurs

25. Tertiary mammals All mammals that passed through the K/T boundary were small and insectivorous Required several million years before even moderately sized mammals appeared About 10 my after the K/T boundary, some specialized mammals appeared Bats Whales Manatees

26. Mesonychid

27. Andrewsarchus

28. Ambulocetus

29. Whale evolution

30. Hominid evolution At least nine species of hominids existed within the past 4 my Species have overlapped in space and in time Ancestor-descendant relationships are not clear

31. Australopithecus

35. Homo habilis

38. “Out of Africa” model Homo erectus spread into several populations across Eurasia from Africa Only one continent where Homo sapiens evolved, and that was Africa Modern characteristics developed first and were then carried out of Africa

39. Fig. 21.15

40. Support for Out of Africa model Oldest known fossil from Ethiopia - 130,000 years old Oldest fossil known outside of Africa and the Middle East is 40,000 years old Implication that H. sapiens evolved in Africa and migrated to Europe and Asia