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Chapter 11: Modern human evolution
Trend across the hominins:
2 mya = multiple hominin genera
200 kya = multiple species of Genus Homo
40 kya = multiple subspecies
0 ya = just Homo sapiens
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Denisovans
Siberia (???-30 kya)-genetic evidence of an extinct hominin
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Homo sapiensCranial-high vertical forehead -protruding chinCC=1350 cm3
Postcranial-longer limbs-gracile (slender)
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Homo sapiens
Anatomically modern Homo sapiens-by 100 kya have the same physical and cognitive abilities modern humans possess
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Homo sapiens
When did the first Homo sapiens evolve?
Where?
How did they interact with the other premodern populations?
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Models for modern Homo sapiens originsRegional Continuity Model: premodern populations in multiple regions simultaneously evolved into a single species: Homo sapiens
-Denies African origins of Homo sapiens
-Lots of gene flow (migration) stopped speciation
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Models for modern Homo sapiens originsRegional Continuity Model versus Partial Replacement Model
The evidence supports the partial replacement model:
-Most genetic diversity in Africa and there's less genetic diversity seen in populations further and further away from Africa
-Mitochondrial DNA sourced to Africa roughly 160 kya
-Only find Neandertal/premodern human interbreeding outside of Africa
-Earliest fossils date to 200 kya and they're found in Africa
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Models for modern Homo sapiens originsReplacement Models: 200 kya H. sapiens emerged in Africa and later migrated to Europe and Asia
Two versions of the replacement model:
Complete replacement: migrants replaced premodern populations-no interbreeding
Partial replacement: early African migrants interbred and partially replaced premodern populations-80-50 kya in Eurasia interbreeding
Anthropologists use the Partial Replacement version of the model because it matches the evidence of interbreeding between modern humans, Neandertal, and other premodern humans.
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Genetic evidence-Modern humans are genetically similar
-Mitochondrial eve found in Africa dated to 160 kya
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Genetic evidenceFounder effect: more genetic diversity in African populations, then
dwindles gradually in populations further outside of Africa
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Genetic evidence for AMH
Admixture
-between non-African humans, Neandertal, and Denisovans
Non-Africans: 1-4% genes shared with Neandertal
Southeast Asians: 1-6% genes shared with Denisovans
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Fossil evidence for AMH
Africa = 200-160 kya-earliest fossils of Homo sapiens
Eurasia = 100 kya-oldest non-African sites-interbreeding = 80-50 kya
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Fossil evidence for AMH
AMH in...
Asia = 45 kya: Niah Cave, Indonesia
Europe = 35 kya: Cro-Magnon, France
Oceania = 30 kya: Lake Mungo, Australia
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Archaeological evidence
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Upper Paleolithic culture and technology
Upper Paleolithic (75-17 kya) innovations-big game hunting-projectile weapons-elaborate burials-body ornamentation, clothing
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Upper Paleolithic culture and technology
Magdalenian (17 kya)
Atlatl -(spear-thrower) and other projectiles
Burins-chisel-tool used to modify wood, bone, softer material
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Upper Paleolithic symbolic behaviorPortable art-engravings, beads, etc
Venuses figurines with realistic and/or exaggerated sexual traits
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Upper Paleolithic sites of symbolic behavior
AfricaBlombos cave, South Africa165-73 kya-Beads, ocher, intentional burials
EuropeLascaux, France 35 kya-cave art
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Upper Paleolithic symbolic behaviorCave art-new technology for aesthetic purposes