Early Human Origins

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Early Human Origins

  1. 1. Early Human Origins The History and Recent Developments in Competing Theories of Human Origins
  2. 2. Overview <ul><li>Terms and Conventions </li></ul><ul><li>Introduction </li></ul><ul><li>Multiregional Hypothesis </li></ul><ul><li>Out-of-Africa 2 Hypothesis </li></ul><ul><li>Sources of Evidence </li></ul><ul><ul><li>Morphological </li></ul></ul><ul><ul><li>Archaeological </li></ul></ul><ul><ul><li>Genetic </li></ul></ul><ul><li>Recent Studies and their Impact </li></ul><ul><li>New Hypotheses </li></ul>
  3. 3. Terms and Conventions <ul><li>African erectus-grade hominids are H. ergaster </li></ul><ul><li>Asian erectus-grade hominids are H. erectus </li></ul><ul><li>European erectus-grade hominids are H. heidelbergensus </li></ul><ul><li>Hominids considered to be H. sapien are known as anatomically modern humans. </li></ul>
  4. 4. Introduction <ul><li>Longstanding Debate </li></ul><ul><li>Multiregional Hypothesis </li></ul><ul><ul><li>Simultaneous origin </li></ul></ul><ul><ul><li>Heavy gene flow </li></ul></ul><ul><ul><li>Genetic drift </li></ul></ul><ul><li>Out of Africa 2 (replacement theory, eve theory) </li></ul><ul><ul><li>AMHs only in Africa </li></ul></ul><ul><ul><li>Migrating populations replaced others </li></ul></ul>
  5. 5. Introduction <ul><li>Background </li></ul><ul><ul><li>H. ergaster OOA around 1.7 mya (OOA1) </li></ul></ul><ul><ul><li>Daughter populations </li></ul></ul><ul><ul><ul><li>In Europe, H. heidelbergensis -> Neanderthals </li></ul></ul></ul><ul><ul><ul><li>In Asia, H. erectus; Java man, Peking man </li></ul></ul></ul><ul><ul><li>AMH in Africa between 160,000 – 130,000 </li></ul></ul><ul><ul><li>AMH in Asia around 90,000 </li></ul></ul><ul><ul><li>What happened in between? </li></ul></ul>
  6. 6. Multiregional Hypothesis <ul><li>Milford H. Wolpoff, 1980 (Wolpoff & Thorne, 1992) </li></ul><ul><ul><li>Regional continuities </li></ul></ul><ul><ul><li>Gene flow in erectus-grade populations </li></ul></ul><ul><ul><ul><li>Single individual </li></ul></ul></ul><ul><ul><li>Orthogenisis </li></ul></ul><ul><ul><ul><li>Intense convergence </li></ul></ul></ul><ul><ul><li>Explains Human races </li></ul></ul><ul><li>Politics </li></ul><ul><ul><li>Racism </li></ul></ul><ul><ul><li>Modern Multiregionalism </li></ul></ul>
  7. 7. Out of Africa 2 <ul><li>AMHs arose 200,000 year in East Africa </li></ul><ul><li>Dispersed in OOA1 pattern </li></ul><ul><li>AMH populations replaced archaic Homo </li></ul><ul><li>No substantial interbreeding </li></ul><ul><li>Human races recent and superficial </li></ul><ul><li>Dominant theory for 16 years </li></ul>
  8. 8. Out of Africa 2
  9. 9. Morphological Evidence <ul><li>Supporting OOA2 </li></ul><ul><ul><li>AMH characteristic gradation in East Africa </li></ul></ul><ul><ul><li>Most Human characterstics present in early H. ergaster populations </li></ul></ul><ul><li>Supporting Multiregionalism </li></ul><ul><ul><li>Regional continuities </li></ul></ul><ul><ul><ul><li>Indonesian H. erectus dentition </li></ul></ul></ul><ul><ul><li>Brain cavity size explosion @ 450,000 ya. (Relethford, 2001) </li></ul></ul>
  10. 10. Morphological Evidence
  11. 11. Archaeological Evidence <ul><li>Study culture like phylogeny </li></ul><ul><li>Acheulean explosion @ 100,000 years. (Templeton, 2002) </li></ul><ul><li>Could be cultural convergence </li></ul><ul><li>Interactions might imply interbreeding </li></ul><ul><li>Weak evidence </li></ul>
  12. 12. The Neanderthal Problem <ul><li>Lebel, 2001l Trinkaus et al , 2003 </li></ul><ul><ul><li>Survey of Neanderthal anatomy </li></ul></ul><ul><ul><li>Indicated substantial interbreeding </li></ul></ul><ul><ul><li>weak evidence </li></ul></ul><ul><li>Duarte et al , 1999 </li></ul><ul><ul><li>Possible neanderthal hybrid </li></ul></ul><ul><ul><li>weak evidence </li></ul></ul>
  13. 13. Neanderthal Problem
  14. 14. The Neanderthal Problem <ul><li>Genetic studies </li></ul><ul><ul><li>No substantial genetic contribution </li></ul></ul><ul><ul><li>Not conclusive </li></ul></ul><ul><ul><ul><li>Limited study regions </li></ul></ul></ul><ul><ul><ul><li>Possible partial sterility, AMH females. Neanderthal males. </li></ul></ul></ul><ul><ul><li>Recent studies show no Neanderthal nuclear DNA </li></ul></ul><ul><ul><ul><li>James P. Noonan et al, 2006 </li></ul></ul></ul><ul><ul><li>Not evidence against Multiregional hypothesis </li></ul></ul><ul><ul><li>Very open, contentious issue. </li></ul></ul>
  15. 15. Genetic Evidence <ul><li>Most important source since 1987. </li></ul><ul><li>Technology </li></ul><ul><ul><li>Haplotype analysis </li></ul></ul><ul><ul><li>Haplogroups </li></ul></ul><ul><ul><li>Valid haplotypes </li></ul></ul><ul><ul><ul><li>Resolution </li></ul></ul></ul><ul><ul><ul><li>Molecular Clock </li></ul></ul></ul><ul><ul><ul><li>Non recombinant </li></ul></ul></ul>
  16. 16. Genetic Studies
  17. 17. Genetic Evidence <ul><li>Cann, R. et al, 1987 </li></ul><ul><ul><li>D-loop of mDNA </li></ul></ul><ul><ul><li>AMH ancestor around 170,000 ya </li></ul></ul><ul><ul><li>All haplogroups outside of African a subset </li></ul></ul><ul><ul><li>Conclusive evidence for OOA </li></ul></ul><ul><ul><li>Classic mitochondrial eve study </li></ul></ul><ul><li>Results duplicated many times </li></ul><ul><li>D-loop problems </li></ul><ul><ul><li>Mutation rate too high </li></ul></ul><ul><ul><li>Molecular clock debated </li></ul></ul>
  18. 18. Genetic Studies <ul><li>Results </li></ul><ul><ul><li>Old Haplogroups not in Africa </li></ul></ul><ul><ul><li>at least two major migrations after OOA1 </li></ul></ul><ul><ul><ul><li>0.42-0.84 MYA and 0.8-0.15 MYA </li></ul></ul></ul><ul><ul><li>Substantial interbreeding </li></ul></ul><ul><ul><li>Most diversity produced in Africa </li></ul></ul><ul><ul><li>Some gene flow from Asia </li></ul></ul>
  19. 19. Genetic Evidence <ul><li>Templeton, 2001 </li></ul><ul><ul><li>Used all possible haplotype areas </li></ul></ul><ul><ul><ul><li>Full mtDNA </li></ul></ul></ul><ul><ul><ul><li>Large portions of Y-chromosome </li></ul></ul></ul><ul><ul><ul><li>Nuclear DNA </li></ul></ul></ul><ul><ul><li>Most accurate Haplogroup study to date </li></ul></ul><ul><ul><li>Computational analysis </li></ul></ul>
  20. 20. Genetic Evidence <ul><li>Implications </li></ul><ul><ul><li>Problems for OOA2 </li></ul></ul><ul><ul><ul><li>Substantial preserved interbreeding </li></ul></ul></ul><ul><ul><ul><li>Haplogroups too old </li></ul></ul></ul><ul><ul><ul><li>Strict replacement model impossible </li></ul></ul></ul><ul><ul><li>Problems for Multiregional hypothesis </li></ul></ul><ul><ul><ul><li>African diversity played major role </li></ul></ul></ul><ul><ul><ul><li>Regional origins not strictly simultaneous </li></ul></ul></ul>
  21. 21. Out of Africa Again and Again <ul><li>(Templeton; 2001, 2006) </li></ul><ul><ul><li>Computational analysis </li></ul></ul><ul><ul><li>Partial replacement model </li></ul></ul><ul><ul><li>Large migrations out of Africa </li></ul></ul><ul><ul><li>Small amount of Gene flow back </li></ul></ul><ul><ul><li>Accounts for all available evidence </li></ul></ul><ul><ul><ul><li>Cultural similarities </li></ul></ul></ul><ul><ul><ul><li>Cranial boom + regional continuities </li></ul></ul></ul><ul><ul><ul><li>Possible neanderthal interbreeding </li></ul></ul></ul>
  22. 22. OOA Again and Again
  23. 23. Citations <ul><li>Cavalli-Sforza, L. and M.W. Feldman. 2003. That Application of Molecular Genetic Approaches to the Study of Human Evolution. Nat Genet. Mar;33 Suppl:266-75. </li></ul><ul><li>Cann, R. L., Stoneking, M. & Wilson, A. C. Mitochondrial DNA and human evolution. Nature 325, </li></ul><ul><li>Lebel, S et al. 2001. Comparative Morphology and Paleobiology of Middle Pleistocene Human Remains from the Bau de L'Audesier, Vaucluse, France. Proc Natl Acad Sci USA. 2001 Sep 25;98(20):11097-102. Epub 2001 Sep 11. </li></ul><ul><li>Relethford, J. H. Genetics and the Search for Modern Human Origins (Wiley, New York, 2001). </li></ul><ul><li>Serre et al. 2004. &quot;No evidence of Neandertal mtDNA contribution to early modern humans&quot;. PLoS Biology 2 (3): 313–7. </li></ul><ul><li>Templeton, A. 2002. Out of Africa again and again. Nature. Mar 7;416(6876):32-3. </li></ul><ul><li>Trinkaus, E., Moldovan, O., Milota, Ş., Bîlgăr, A., Sarcina, L., Athreya, S., e al. (2003). An early modern human from the Peştera cu Oase, Romania. PNAS, 100, 11231-11236. </li></ul>
  24. 24. Images <ul><li>Slide 6: Public domain, wikipedia. </li></ul><ul><li>Slide 7: Public domain, talk.origins </li></ul><ul><li>Slide 8: Public domain, Wikipedia </li></ul><ul><li>Slide 10: http://contradictions.darwin.ws/ - Debunking Creationism </li></ul><ul><li>Slide 11: Public domain, Wikipedia </li></ul><ul><li>Slide 13: Obtained from respective news sites </li></ul><ul><li>Slide 16: Public domain, Wikipedia. </li></ul><ul><li>Slide 19: http://www.terradaily.com/reports/New_Analysis_Shows_Three_Human_Migrations_Out_Of_Africa.html </li></ul><ul><li>Slide 22: Templeton, 2001 </li></ul>

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