2 mya = multiple hominin genera Chapter 11: Modern human ... · 1 Chapter 11: Modern human...

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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