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Lab Final Monday 6:30 PM

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  1. Lab Final Monday 6:30 PM Optional Lecture Exam 4Monday 6:00 PM scantron

  2. Today: • Human EvolutionDarwin’s Finches Survivor Game • Fossil Lab and Review

  3. Class of 2011 • CONGRATULATIONS GRADUATES!

  4. Primate and Human Evolution

  5. Who are we? • What is the human genealogy? • Who is the closest genetic relative? • Why are we different? When did we diverge? • What makes us human? • Are we still evolving? • But first, how was the stage set for humans?

  6. Maiasaura, a Late Cretaceous ornithopod, nested in colonies in northern Montana

  7. Meteorite Impact Mass Extinction

  8. Global temperature models60 ma to present

  9. Pleistocene CO2 Levels and Glacial Periods

  10. Our family goes back farther than we thought • Sahelan-thropustchadensis, • the oldest known hominid • nearly 7 million years old, • discovered in 2002 in Chad • “Tormai” – Hope of Life

  11. Humans and Chimpanzees Diverged • human-chimpanzee stock separated • from ancestral gorillas about 8 million years ago

  12. Humans and Chimpanzees Diverged • human-chimpanzee stock separated • from ancestral gorillas ~ 8 million years agoSahelanthropus tchadensis~7 my ago • at or near the time • when humans and • chimpanzees diverged

  13. humans separated from chimpanzees about 5 million years ago

  14. Oldest Hominid Sahelanthropustchadensis -- mosaic of primitive and advanced features • The small brain case and most of the teeth are chimplike • The nose, which is fairly flat, • and the prominent brow ridges • are features only seen, until now, • in the human genus Homo

  15. Continuing Discoveries Change Our Ideas • As recently as 2000, • the earliest fossil evidence of hominids • was from 4.4-million-year-old rocks in eastern Africa • Since then, as just noted, discoveries have pushed that age back to almost 7 million years

  16. paleoanthropologists now think • that human evolution is not a straight line • The lines branched many times • According to this “bushy” model key traits evolved more than once • upright walking, • manual dexterity • “large” brain • This probably produced many evolutionary dead-ends

  17. “Bushy” Model of Human Evolution

  18. Trends in Primates • These include changes in the skeleton • and mode of locomotion, • an increase in brain size, • a shift toward smaller, fewer, • and less specialized teeth,

  19. Trends in Primates • the evolution of stereoscopic vision • and a grasping hand with opposable thumb • Not all these trends took place in every primate group, • nor did they evolve at the same rate in each group

  20. Classification of Primates • The prosimians, or lower primates, • while the anthropoids, or higher primates, • include monkeys, apes, and humans

  21. Tarsier • LowerTarsiers are prosimian primates

  22. Anthropoid Superfamilies • Anthropoids are divided into three superfamilies • Old World monkeys, • New World monkeys, • and hominoids

  23. Great Apes

  24. Chimpanzee • Chimpanzees

  25. One of the Earliest Anthropoids • Skull of Aegyptopithecus zeuxis, • one of the earliest known anthropoids

  26. Hominoids • evolved in Africa, • The hominids (family Hominidae) • the primate family that includes present-day humans • and their extinct ancestors • have a fossil record extending back • to almost 7 million years

  27. Hominids are bipedal; • that is, they have an upright posture, • which is indicated by several modifications in their skeleton

  28. Comparison of Locomotion • Comparison between quadrupedal and bipedal locomotion • in gorillas and humans • In gorillas the ischium bone is long • and the entire pelvis is tilted toward the horizontal

  29. Comparison of Locomotion • In humans the ischium bone is much shorter • and the pelvis is vertical • Comparison between quadrupedal and bipedal locomotion • in gorillas and humans

  30. Larger Reorganized Brain • hominids show a trend • toward a large and internally reorganized brain

  31. Larger Reorganized Brain • a present-day human

  32. Other Distinguishing Features • Other features that distinguish hominids • a reduced face • and reduced canine teeth, • omnivorous feeding, • increased manual dexterity, • and the use of sophisticated tools

  33. Response to Climatic Changes? • Many anthropologists think • these hominid features evolved in response • to major climatic changes • during the Miocene into the Pliocene • During this time, vast savannas • replaced the African tropical rain forests • where the lower primates • had been so abundant

  34. Australopithecines • Australopithecine is a collective term • for all members of the genus Australopithecus • Currently, five species are recognized: • A. anamensis, • A. afarensis, • A. africanus, • A. robustus, • and A. boisei

  35. Australopithecus afarensis • Australopithecus afarensis, • which lived 3.9–3.0 million years ago, • was fully bipedal • and exhibited great variability in size and weight • Members of this species ranged • from just over 1 m to about 1.5 m tall • and weighed between 29 and 45 kg

  36. Lucy • This recon-struction • illustrates how adaptations in • Lucy’s hip, leg and foot • allowed a fully bipedal • means of locomotion • A reconstruction of Lucy’s skeleton • by Owen Lovejoy • and his students at Kent State University, Ohio • Lucy is an ~ 3.5-million-year-old • Australopithecusafarensis individual • whose fossil remains were discovered by Donald Johanson

  37. Hominid Footprints • Preserved in volcanic ash at Laetoli, Tanzania • Discovered in 1978 by Mary Leakey, • these footprints proved hominids • were bipedal walkers at least 3.5 million years ago • The footprints of two adults and possibly those of a child • are clearly visible in this photograph

  38. Hominid Footprints • Most scientists think the footprints • were made by Australopithecus afarensis • whose fossils are found at Laetoli

  39. Brain Size of A. afarensis • A. afarensis had a brain size of 380–450 cubic centimeters (cc), • larger than the 300–400 cc • of a chimpanzee • but much smaller than that of present-day humans (1350 cc average)

  40. Landscape with A. afarensis • Re-creation of a Pliocene landscape • showing members of • Australo-pithecusafarensis • gathering and eating • various fruits and seeds

  41. Skull of A. africanus • A reconstruction of the skull • of Australopithecus africanus • This skull, • known as that of the Taung Child, • was discovered by Raymond Dart in South Africa in 1924 • and marks the beginning of modern paleoanthropology