Ant 2511 09Summer A THE ORIGINS AND DISPERSAL OF MODERN HUMANS Introduction First modern Homo sapiens evolve in Africa (200,000) All contemporaries are placed in this species First are descendents of premodern humans Especially from African populations of H. heidelbergensis Approaches to Understanding Modern Human Origins 1) Complete replacement 2) Regional continuity And a third compromising theory 3) partial replacement Complete Replacement Model (Recent African Evolution) Modern populations arose in Africa (only) No species - no admixture Migrated from Africa, replacing populations in Europe and Asia. (“single origin”) Mitochondrial DNA Evidence of African origin Genetic data - living peoples Mitochondrial DNA (inherited through mother) Concluded the world’s population descended from single African lineage. Y-chromosome More genetic data Y-chromosome (male chromosome) Variation in DNA less compared to other primates Bolsters complete replacement model Neandertal DNA Distinctive 1
Strong direct evidence of genetic discontinuity between Neandertal and early fully modern humans Argues for substantial replacement The Partial Replacement Model Gradual dispersal of H. sapiens sapiens out of Africa. Modern humans mixed with local archaic populations in Eurasia Some interbreeding The Regional Continuity Model (Multiregional Evolution) Local populations in Europe, Asia and Africa evolve into anatomically modern humans Why Similar Gene flow between archaic populations Moderns humans not separate species Never independent. Always single species Seeing the Big Picture Current evidence that earliest modern humans from Africa The Earliest Discoveries of Modern Humans Africa Early fossil fully anatomically modern forms
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