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The origin and dispersal of modern humans

The origin and dispersal of modern humans. Oct. 21, 2008. Introduction. ~200-150 Ka the first modern Homo sapiens evolved in Africa; most likely from some African Homo heidelbergensis population When did they first appear? Where did the transition take place?

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The origin and dispersal of modern humans

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  1. The origin and dispersal of modern humans Oct. 21, 2008

  2. Introduction • ~200-150 Ka the first modern Homo sapiens evolved in Africa; most likely from some African Homo heidelbergensis population • When did they first appear? • Where did the transition take place? • What was the pace of evolutionary change? • How did the dispersal of modern humans take place? • Why so successful?

  3. Approaches to understanding Modern Human Origins • Complete replacement model • Regional continuity, or multiregional evolution • Partial Replacement

  4. Complete Replacement Model • Recent African Evolution • Stringer & Andrews, 1988 • Anatomically modern humans arose in Africa within the last 200 Ka as a result of a biological speciation event. • As such, interbreeding with archaic hominids was not possible

  5. mtDNA and Y-chromosomal evidence on Modern Human Origins • Neither is significantly altered during recombination or sexual reproduction • African populations are the most genetically diverse • Powerful direct evidence of a genetic discontinuity between Neanderthals and Modern Humans • Problem – Contamination, lost lineages and population bottlenecks related to Pleistocene climatic fluctuations, volcano eruptions & differences in sex dispersal?

  6. Partial Replacement (or Assimilation) Model • Some interbreeding occurred between modern humans and archaic hominids • No speciation event occur, all hominids (from the Middle Pleistocene onwards) should be considered members of Homo sapiens • Although, African populations probably have made the most contributions to modern populations; ‘mostly out of Africa’

  7. The Regional Continuity Model (or Multiregional Evolution) • M. Wolpoff & A. Thorne • Local populations in Europe, Asia and Africa continued their evolutionary development from premodern Middle Pleistocene forms to anatomically modern humans • Assumptions – H. sapiens did not exclusively originate in Africa; Gene flow between regional populations; single, though polytypic species

  8. Seeing the big picture • Disagreements are overstated and overdramatized • High congruence between genetics and fossil evidence • “strong” multiregional model highly unlikely • Interbreeding between hominid species most likely was possible, but didn’t happen very often

  9. The Earliest discoveries of Modern humans • Africa: Omo-Kibish (195 Ka), Herto (154-160 Ka), Border (60-80 Ka?), Blombos (73-140 Ka) and Klasies River Mouth (120 Ka) Caves • The Near East: Skhul (100-130 Ka) and Qafzeh (92-120 Ka), Israel

  10. The Earliest discoveries of Modern humans • Central Europe: Mladec, Czech Republic (31 Ka) and Oase Cave (35 Ka), Romania • Western Europe: Cro-Magnon, France (30 Ka) and the Aurignacian (Upper Paleolithic stone tool industry). • Asia: Zhoukoudian Upper Cave (27 Ka) and Tianyuan (40 Ka), China • Niah Cave (35-45 Ka), Borneo • Australia: Lake Mungo (25-60 Ka), Kow Swamp (9-14 Ka)

  11. Something new and different • By 25 Ka modern humans occupy most major areas of the Old World and begin entering the New World ~15 Ka • Remnant hominids in East Asia?: Homo erectus (>30-50 Ka) and Homo floresiensis (~18 Ka; 95-74 Ka to >12)

  12. Homo floresiensis • The island of Flores, Indonesia • ~18 Ka

  13. Technology & Art in the Upper Paleolithic • European Stone tool industries: • Magdalenian, 17 Ka • Solutrean, 21 Ka • Gravettian, 27 Ka • Aurignacian and Chatelperronian, 35-40 Ka • Africa – beads made from ostrich egg shells ~38-50 Ka. Pinnacle point at 165 Ka with ocher, blades and exploitation of shellfish. Bone tools at Katanda, DRC, 80 Ka.

  14. Summary of Upper Paleolithic Culture • Stone tool industries of Europe - • Magdalenian, 17 Ka; atlatal and bow & arrow, cave art • Solutrean, 21 Ka; artistic parallel flaked lance heads • Gravettian, 27 Ka; Portugal child burial with ochre • Aurignacian (associated with the first modern humans in Europe) and Chatelperronian (associated with some of the last Neanderthals), 35-40 Ka • Burials and grave goods • Venus figurines • Engravings • Climatic Fluctuations

  15. Abrigo do Lagar Velho, Portugal (Gravettian 24.5 Ka)

  16. Images of early Modern humans Cro-Magnon Skhul • Characteristics of Modern Humans: • Vertical forehead • Canine fossa • Relatively small brow ridges and face • Pyramidal mastoid process • Definite chin

  17. Klasies River Mouth Qafzeh

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