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Primate Evolution

Primate Evolution. 5 November, 2007. Time, time, time…. Origin of life. Earth’s origin. Themes. Bush analogy (vs. ladder) “Extinction is the rule” Incompleteness of the fossil record “Once we were not alone” The nature of the evidence Fossils Molecular- protein/DNA. Class- Mammalia.

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Primate Evolution

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  1. Primate Evolution 5 November, 2007

  2. Time, time, time…. Origin of life Earth’s origin

  3. Themes • Bush analogy (vs. ladder) • “Extinction is the rule” • Incompleteness of the fossil record • “Once we were not alone” • The nature of the evidence • Fossils • Molecular- protein/DNA

  4. Class- Mammalia • Derived from a branch of the reptiles- the therapsids • ~200 M ybp

  5. Class- Mammalia • Characteristics • Hair • Mammary Glands (w/ or w/o nipples) • “Warm blooded” • Egg layers- earliest form= “monotremes” • Lots of unique anatomical features (1 aorta, 3 middle ear bones, one jaw bone (dentary), etc…)

  6. Mammals, continued… • Anatomy • One jaw bone • 3 middle ear bones • Specific arterial structures • Initially small, rat-like, nocturnal insect eaters

  7. Earliest Mammals • Modern descendents- platypus (of Australia) & echidna (of New Zealand)

  8. “Advanced” Mammals- the “Placentals” • ~ 100 M ybp- “Age of the Dinosaurs” (Cretaceous era) • (older fossil?- ~ 130 M ybp, 1 meter in length) • “Live bearing mammals” • Internal development • Some form of connection between mother and fetus= “placenta”

  9. Two parallel lineages: • Marsupial mammals- kangaroo, wallaby, opossum • Young “born” only partially developed • No eggs- internal (initial) development- rudimentary placenta • Well-developed nipples- young attach to complete development

  10. Live bearing Mammals • “Eutheria” • True placenta • Offspring spend longer developing in mother

  11. The reality of the situation at ~ 65 M ybp • Mammals (monotremes, marsupials & eutherians) were all a very small part of animal diversity • Eutherians represented by a very small number of small, nocturnal, shrew-like animals • The “K/T Boundary” (cretaceous/tertiary)

  12. The reality of the situation at ~ 65 M ybp • The “K/T Boundary” (cretaceous/tertiary)- one of many historical “Mass extinctions” (many living groups, including the dinosaurs)

  13. Mammalian diversification • Explosive diversity of mammalian types in “vacuum” of rapid dinosaur extinctions- especially eutherians

  14. ~60 M ybp • Primates (taxonomic Order) • Tree-dwelling • Omnivorous • Branchiate- swing by arms • Dexterous hands • Claws replaced by nails • Opposable thumb • Forward-facing eyes, binocular vision • Parental care

  15. ~ 58 M ybp Ancestral Primate • “Dry-nosed” primates • Mostly diurnal • Specialized hands and • feet for grasping • Tarsiers + Monkeys & Apes • (a.k.a. “Simians”) • First- cat-sized and arboreal • “Wet-nosed” primates • Mostly nocturnal • Tree-dwelling • Lemurs

  16. ~ 40 M ybp Ancestral Simian • Old-World Monkeys + others • Africa & Asia • Simple, no tail • Narrow nose • Tree-dwelling • Mostly diurnal • Flat fingernails • Baboon, Macaque, Great • Apes Atlantic Ocean • New-World Monkeys • N/S America • Long prehensile tail • Flat nose • Tree-dwelling • Mostly nocturnal • Capuchin, Marmosets, • Howler monkey

  17. ~ 25 M ybp Ancestral Old World Monkeys, et al • (Apes) “Hominoids” • Mostly arboreal • Africa, Asia • Other anatomical • features • Gibbon, Great Apes • Old-World Monkeys • Baboon, Macaque, Proboscis • Monkey

  18. ~ 18 M ybp Ancestral Hominoids The “Hominidae” Humans +Great Apes • “Lesser Apes” • Tree-dwelling • Strong brachiating • Gibbons

  19. The “Hominidae”

  20. The “Hominidae” The “Hominidae” ~ 14 M ybp Sivapithecus (Ramipethecus)- fossil ~ 14 M ybp Initially thought to be an early “homininae” The “Homininae” Evolved in Africa: Gorilla, Chimp, Pygmy Chimp, Human Orangutans Asia

  21. The “Homininae” The “Homininae” ~ 7 M ybp The “Hominini” Humans, Chimpanzee, Pygmy Chimpanzee (Bonobo) • Gorillas • 2 (4?) species • Knuckle-walk • Intelligent • Western & Eastern • species (w/ subspecies)

  22. The “Hominini” The “Hominini” 6- 7 M ybp The “Hominids” Humans + fossils leading to modern humans Molecular evidence- “Molecular clocks” Antibody specificity DNA hybridization Chimpanzee Larger, stockier More aggressive Male-dominated social groups Bonobo Gracile More cooperative, more sexual Female-dominated Social groups

  23. The “Hominids” • Bipedal • Large brain • Small canine teeth • Later: • Tool production • Language • Art

  24. BREAK TIME

  25. B D G E F A

  26. Raymond Dart- 1924Australopithecus africanus

  27. Donald JohansenAustralopithecus afarensis

  28. 1994-East Africa & Chad

  29. Importance of A. afarensis “Gracile” lineages “Robust” lineages

  30. “Once we were not alone”

  31. B Chimp Gorilla E D C G

  32. Homo sapiens as the “wanderer”The “out of Africa” theory Years before present (byp)

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