Chapter 11 April 2, 2012

Climate and Human Evolution Global Warming and Mammal Size As temperatures increased, their body size decreased. Temperature-size rule Epigenetic changes Blue eyes Smallpox

Sahelanthropus tchadensis “Toumai” Known from a single skull, 4 jaw fragments, and a few teeth Flooded woodland/grassland with distinct dry season 6 to 7 myo

Orrorin tugenensis Moved on the ground using all four limbs, but also moved around in trees Tropical forest environment 6.2 to 5.65 mya

Australopithecines Appeared between 4 and 3.8 mya Disappeared by 1 mya Fossils found only in Africa 3.3–5 feet; 66–132 pounds; small brains Closer to modern chimps and gorillas than modern humans No evidence of tool making or fire use Ate nuts and grasses

Australopithecus sediba Ma descendant of Australopithecus africanus The australopithecine most closely resembling Homo South Africa It shares a number of traits with Homo erectus mosaic evolution

Skeletons currently on display at the National Museum of Natural History: (left to right) Homo erectus, 1 million years old; Australopithecus afarensis, 2.5 million years old; Homo neanderthalensis, 32,000 to 100,000 years old. Researchers are using ancient remains like these to learn more about the effects climate change may have had on evolution.

Early Homo Oldest Homo fossils 2.5 myo and from Olduvai Gorge, east Africa Homo habilis (handy man) Small hominid Bipedal Increased brain size Manufacture and use of specialized tools Oldowan Tradition

Homo habilis

Homo erectus Acheulean Tradition

Homo sapiens More prominent brow and thicker skull than modern- day humans Appeared 400,000 years ago in Europe, Africa, and Asia Eve Hypothesis – all modern humans descended from one African Homo sapiens female that lived 200,000 years ago Multiregional Model – Homo sapiens evolved from Homo erectus separately at two or more geographic locations Most Anthropologists support Out of Africa Model

Homo sapiens neanderthalensis Fossils from 130,000 to 35,000 years ago Europe and Near East Only hominids that unquestionably did not evolve in sub-Saharan Africa Not ancestral to modern humans Evolved from archaic Homo sapiens Mousterian Tradition Fire, clothing, shelter, rituals, music

Homo sapiens sapiens Adapted to warm conditons and open countryside Human Revolution – 50,000 years ago rapid expansion inside of and out of Africa; creating art and ritual burials