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  1. Human Evolution

  2. Outline • Evolution of Primates • Mobile Limbs • Binocular Vision • Evolution of Early Hominids • Evolution of Later Hominids • Evolution of Early Homo • Modern Humans • Human Variation

  3. Evolution of Primates • The evolution of primates is characterized by trends towards: • Mobile limbs • Grasping hands • A flattened face • Binocular vision • A large, complex brain, and • A reduced reproductive rate

  4. Primate Diversity

  5. Mobile Limbs • Hands and feet • Most primates have flat nails • 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

  6. Evolution of Primate Hand

  7. Binocular Vision • Stereoscopic vision • Depth perception • Allows primates to make accurate judgments about distance and position of adjoining tree limbs

  8. Binocular Vision

  9. Primate Characteristics • Opposable thumb • Nails instead of claws • Single births • Binocular vision • Expanded, complex brain • Emphasis on learned behavior

  10. Evolution of Primates • Prosimians were the first type of primate to diverge from the human line • Surviving anthropoids are classified into three superfamilies • New World monkeys • Old World monkeys • Hominoids

  11. Evolution of primates

  12. Evolution of Hominids • Proconsul is believed ancestral to hominids • Phylogenetic tree indicates humans are most closely related to African apes • Genetic changes used as a molecular clock to measure relatedness of different groups • Last common ancestor appears to have lived about 7 mya

  13. Monkey SkeletonCompared to Proconsul Skeleton

  14. Hominids • Hominid fossils: • Must have an anatomy suitable for standing erect and walking on two feet • Bipedalism • Skeletal differences between humans and apes largely because: • Humans are bipedal, while • Apes are quadrupedal

  15. Adaptations for Standing

  16. Australopithecines • Australopithecines: • Evolved and diversified in Africa 4 mya • Possibly a direct ancestor of humans • Southern Africa • Australopithecus africanus • Eastern Africa • Australopithecus afarensis

  17. Human Evolution

  18. Australopithecus afarensis

  19. Evolution of Early Homo • Homo habilis • Dated between 20 an 19 mya • May be ancestral to modern humans • Skulls suggest portions of the brain associated with speech were enlarged • Ability to speak may have led to hunting cooperatively and the advent of culture

  20. Homo erectus • Homo erectus and similar fossils • Found in Africa, Asia, and Europe • Dated between 19 and 03 mya • Larger brain and flatter face than Homo habilis • Much taller than previous hominids • Thought to have first appeared in Africa and then migrated into Asia and Europe • First hominid to use fire

  21. Homo ergaster

  22. Evolution of Modern Humans • Most researchers believe Homo sapiens evolved from Homo erectus • Multiregional Continuity Hypothesis • Similar evolution occurred in many different places • Out-of-Africa Hypothesis • H. sapiens evolved from H. erectus only in Africa, and thereafter migrated to Europe

  23. Evolution of Modern Humans

  24. Neanderthals • Neanderthal (H. neanderthalensis) skeletons were first discovered in Germany’s Neander Valley • Skeletons date back 200,000 years • Massive brow ridges with protruding nose, jaws, and teeth • Heavily muscled • Culturally advanced • Manufactured variety of tools

  25. Neandertals

  26. Cro-Magnons • Oldest fossils to be designated H. sapiens • Modern humans who entered Asia and Europe from Africa 100,000 years ago • Made advanced stone tools • Accomplished hunters • Hunted cooperatively • First to have language

  27. Cro-Magnons

  28. Human Variation • Hypothesized that human variations evolved as adaptations to local environmental conditions • Bergmann’s Rule - Animals in colder regions of their range have a bulkier body build • Allen’s Rule - Animals in colder regions of their range have shorter limbs, digits, and ears • Comparative study of mitochondrial DNA • Suggests human populations have a common ancestor no more than a million years ago

  29. Ethnic Groups

  30. Review • Evolution of Primates • Mobile Limbs • Binocular Vision • Evolution of Early Hominids • Evolution of Later Hominids • Evolution of Early Homo • Modern Humans • Human Variation

  31. Human Evolution