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

• 1.95-1.78 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