10: genus homo

Genus Homo

• Hominin = a habitually bipedal primates.

Early Hominins

• All the early hominins were found in Africa. They all were relatively small brained and used comparatively simple technology.

Emergence of Genus Homo

• Around 2.2 million years ago, we start seeing the emergence of Genus Homo in Africa.

Genus Homo: the generalities

• Larger brains than Early Hominins

• Skulls are less ape-like.

• More complex culture, including the use of stone tools.

Homo habilis

• Homo habilis (literally: handy man) is one of the earliest members of Genus Homo to be identified.

• Despite having a larger brain then earlier hominins, Homo habilis still had archaic features.

Archaic Features

• Brow Ridges

• Sloping Forehead

• Prognathism

• Lack of a chin

Homo habilis

• Had an average brain size of around 680ml, nearly 50% larger than previous hominins.

• First fossil we associate with the use of stone tools.

Homo habilis skull (left)vs. Australopithecus (right)

Stone Tools

Homo ergaster 1.9-1.4 mya

• Homo ergaster is a possible ancestor of Homo erectus and possibly also an ancestor of Homo heildebergensis.

Homo erectus 1.8 mya to 50,000 years ago.

Homo erectus

• Larger brain: 1000ml on average (and as large as 1250ml).

• Prominent brow ridges and prognathism

Migration

• Homo erectus is widely believed to be the first hominin to migrate out of Africa.

“Tuang Child” Endocast

Endocast Reconstruction of Homo erectus

Brain Regions

Speech

• The bones attached to the larynx and pharynx indicate Homo erectus had the ability to make the sounds necessary for speech…

• Furthermore the neural structures for speech production and recognition are present in the brains of Homo erectus.

Homo heidelbergensis

• Found about 400-600,000 years ago

• Was possibly the first hominin to bury their dead.

• May be the direct ancestor of both Homo sapiens and Neanderthals.

Homo neanderthalensis

• Homo neanderthalensis or Neanderthals: between 225,000 and 28,000 years ago.

• Neanderthals lived through the Pleistocene a period characterized by a series of glacial advances (Ice Age).

Neanderthals

• Large brains• Heavy brow ridges

and sloping forehead

• Built heavier and stockier than contemporary humans

Neanderthal Adaptations to the Cold

• Short, stocky bodies: conserved heat in the core.

• Long, broad noses would have warmed the cold air that they inhaled.

Humans vs. Neanderthal

Interbreeding?

• There is evidence that the majority of people of non-African origin have between 2 and 4% Neanderthal DNA.

• This would imply, of course, that modern humans and Neanderthals were the same species. They should be referred to as Homo sapiens sapiens and Homo sapiens neanderthalensis.

Modern Humans

• Modern Humans (Homo sapiens) probably emerged around 150,000 years ago.

• Have flat faces• Lack heavy brow ridges• Have “globular” skulls rather than

elongated ones.• Presence of a chin

Modern Humans

• The earliest anatomically modern humans are found in Africa.

Modern Human Skull

Bering Strait Land Bridge