Human Evolution

1. Human Evolution Chapter 32-Mader

2. Overview • Evolution of Primates • Evolution of Hominids • Focus on Homo • Human Variation • Humans as a selective agent

3. Early Primates • Prosimians (~58mya) • Monkeys (35mya) • Apes (23mya) • Hominids (~6mya)

4. First Arboreal Mammals • The first arboreal mammals probably resembled shrews: • long snouts. • Good sense of smell. • Probably nocturnal. • Very active. • CLAWS

5. First Arboreal Mammals?

6. Eosimias • The First Primate? • Comparison with tree shrew

7. Prosimians Lemurs Tarsiers Pottos Loris

8. Tarsier

9. Ring tailed lemur

10. Indri

11. Aye aye what do they sound like? This

12. Slender loris

13. Primate Characteristics • What is the major selective pressure associated with life in the trees? • How are primates adapted to this life?

14. Binocular Color Vision

15. Primate Hands

16. Mobile Limbs • Most primates have flat nails as well as sensitive pads on the undersides of fingers and toes. • Many also have both an opposable big toe and thumb. • Mobile limbs and clawless opposable digits allow primates to freely grasp and release tree limbs.

17. Other important features • Upright posture. • Small litter size. • Expanded forebrain, larger brain capacity. Advantages?

19. Two main groups of primates: • 1. Prosimians – lemurs, lorises, pottos & tarsiers • 2. Anthropoids – monkeys, apes and man

20. Prosimians Lemurs Tarsiers Pottos Loris

21. ANTHROPOIDS • 2. Anthropoids = monkeys + apes + man • Monkeys: • Old world monkeys • New world monkeys Old World Monkey: Long snout Close nostrils Non-prehensile tail New World Monkey: Flat face Wide nostrils Prehensile tail

22. Taxonomy • Anthropoids= Hominoids + monkeys • Hominoids= Asian and African Apes + Hominids • Hominids= Humans

23. Proconsul- Ancestor to Hominoids?

24. Proconsul A skull of Proconsul africanus from the Kenya National Museum.

25. Selective pressures East Africa Rift Valley

27. Skull Comparisons:

28. Sahelanthropus tchadensis • 6 to 7 million years ago • Flat face like Homo • Cranial capacity about the same as a chimp • Walked upright

29. Hominids • Bipedal primates.

30. To be Human • standard primate characteristics • upright, bipedal posture • much expanded brain • well defined sexual dimorphism • hidden estrus • altered female sexual response • extended childhood • language • society • culture

31. Homo erectus, Australopithecus,& Human

32. Map of Australopithecine Finds Map of Australopithecus sites in Africa, with a focus on the East African rift valley and limestone caves of South Africa.

33. “Lucy” Australopithecus afarensis An Example of Mosaic Evolution

35. A. boisei A. afarensis A. africanus A. robustus

36. Human Ancestors

37. Human Evolution

38. Australopithecus africanus • 2.8 million years ago • Cranial capacity 460 cc

39. Genus Homo

40. Homo habilis Brain~600cc “Handy Man” Olduwan tools Speech? Artist’s representation of a Homo habilis band as it might have existed two million years ago.

41. Oldowan Tools

43. Homo erectus • “Upright Man” • Larger brain than H. habilis • Migrated • Acheulean tools • More advanced culture?

44. Homo erectus

45. Homo erectus

46. Trends in Skull Development

48. Neanderthals • Neanderthal (H. neanderthalensis) skeletons were first discovered in Germany’s Neander Valley. • Skeletons date back 200,000 years.