The Pleistocene Epoch 1

The Pleistocene Epoch 1

Tuesday - Recall the big deal about the hominins Hominins - groups us and our bipedal ape-like ancestors Four evolutionary trends ~ 7 mya divergence from apes Adopted the following adaptations/derived characteristics Bipedalism Generalized dentition Increased reliance on material culture Increased brain size 2

Tracking modern human origins Regional Continuity Model 3 Hypothesis: certain local populations in Europe, Asia, and Africa evolved from previous forms to anatomically modern humans Significant amounts of gene flow occurred between various geographically dispersed populations -prevents speciation from occurring Explains: how so many populations evolved with similar morphology

Tracking modern human origins Replacement Models Hypothesis: modern humans first evolved in Africa and later dispersed to other parts of the old world replacing local populations Complete replacement: anatomically-modern humans arose in Africa 200 kya and eventually replaced premodern populations in Asia and Europe Partial replacement: same thing but factors in recent molecular evidence of interbreeding between modern humans and local populations (1-4%). -contemporary Africans lack Neandertal genes - interbreeding occurred after humans left Africa 80-40 kya

Modern human sites of note Africa The Near East Asia Australia Central Europe Western Europe

Technology and Art of the Upper Paleolithic Europe - Upper Paleolithic ~40 kya Five different industries of note Chatelperronian Aurignacian Gravettian Solutrean Magalenian Warming trends created a "hunter's paradise"

Neandertal material culture * Neandertals improved previous techniques by inventing a new tool tradition, Mousterian. -They then trimmed the flakes into various forms, such as scrapers, points, and knives. * This industry is characterized by a larger proportion of flake tools than is found in Acheulian tool kits.

Subsistence Remains of animal bones demonstrate that Neandertals were successful hunters. Used close-proximity spears for hunting (spear thrower and bow and arrow weren t invented until the Upper Paleolithic). Patterns of trauma in Neandertal remains match those of contemporary rodeo performers, indicating close proximity to prey.

Speech and Symbolic Behavior Prevailing consensus has been that Neandertals were capable of articulate speech. Even if Neandertals did speak, they did not have the same language capabilities of modern Homo sapiens.

Burials Neanderthals buried their dead. Their burials included grave goods like animal bones and stone tools. They placed the bodies of their dead in a flexed position.

Chatelperronian -Upper Paleolithic industry found in France and Spain -blade tools -used by Neandertals. Suggestive of some cultural hybridization

Ch 11 Modern Homo sapiens 12

Modern humans - morphology and overview Anatomically modern human = AMH *Continued evolutionary trends: bipedalism, tool manufacturing, dental reduction, brain size 13

Origins and dispersal - Regional Continuity Model Question: Why is there uniform morphology across populations? Regional Continuity Model Milford Wolpoff -Local populations in Europe, Asia, and Africa evolved from Middle Pleistocene hominins to AMH Confirms the hypothesis -Frequent migrations between the different geographically-dispersed premodern populations during Pleistocene SO: gene flow prevented local populations from evolving separately Disconfirms the hypothesis Recent genetic data ultimately fails to confirm the multiregional models 14

Origins and dispersal - Replacement Models Complete Replacement -African origin ~200 kya then dispersed and replaced Old World populations -no interbreeding with premodern H. sapiens Disconfirms the hypothesis Newer molecular evidence of interbreeding between humans and Neandertals Partial Replacement Model(s) SO: revise: AMH emerged in Africa and then interbred with premodern humans in the various regions Confirms the hypothesis -African origins but 1-4% interbreeding between AMH and premodern populations Modern Africans lack Neandertal genes - so interbreeding likely occurred AFTER AMH left Africa ~80-50 kya 15

Important human fossil finds Africa * Omo Kibish, Ethiopia - earliest fossils for Homo sapiens radiometrically dated ~195 kya * Herto, Ethiopia ~160-154 kya based on cranial morphology (nearly identical to modern cranial morphology) Fossil finds used to argue for AMH originating in Africa Near East * Skhul and Qafzeh Caves; Israel -both sites ~130-100 kya and 120-90 kya, respectfully with the remains of 30 individuals retaining some premodern human traits Note: Tabun site has Neandertal dated ~120 kya which adds some support to the area being a place where AMH and Neandertal interbred 16

Important fossil finds Asia * Zhoukoudian Caves again -AMH dated ~27 kya Oceania -All Australians descending from participants of a single migratory event ~50 kya -AMH inhabited areas around New Guinea and Aus ~50 kya * Lake Mungo - 30-25 kya according to archaeological finds 17

Modern human/upper paleolithic culture Upper Paleolithic ~40 kya in Europe -emergence of new tool types made of materials like bone, antler, etc Cultural finds in Eurasia feature elaborate burials with grave goods Warming trend ~30 kya resulted in tundra and steppe across Eurasia where large game was hunted Intense period of glaciation ~20 kya 18

Modern human/upper paleolithic culture Magdalenian -spear thrower - atlatl appears Punch blade technique standardized blades for various usages - burins and borers Hypothesis: more effective tools and usage of fire aided in meat processing might have played a role in AMH dental reduction 19

Modern human/upper paleolithic culture -emergence of cave paintings in W Europe and portable art Venus figurines -function/purpose of cave art not fully understood Rock art also found in Africa dating ~28 kya Also find finely crafted bone tools dated ~80 kya 20

Some Ch 12 - Biocultural Evolution -human evolution makes sense only in a cultural context Sickle-cell trait - adopting slash-and-burn agriculture resulted in humans living closer to/in mosquito breeding areas -so HbS became more frequent in the population -interacted with DDT Lactose intolerance - produce less of the enzyme lactase Lactase persistence - European groups sharing descent from Middle Eastern populations who were pastoralists ^-Cultural dependence on milke increased the frequency of lactose tolerance in populations via natural selection Examples that we're still evolving? 21

The Pleistocene Epoch 22