12.6 Primate Evolution How did modern humans evolve?

12.6 Primate Evolution

12.6 Primate Evolution

How did modern humans evolve?

12.6 Primate Evolution

KEY CONCEPT Humans appeared late in Earth’s history.

12.6 Primate Evolution

Humans share a common ancestor with other primates.

• Common ancestor of all primates probably arose before the mass extinction that ended the Cretaceous Period.

• Primates are mammals with flexible hands and feet, forward-looking eyes and enlarged brains.

12.6 Primate Evolution

• Primates evolved into prosimians and anthropoids.

– Prosimians are the oldest living primates.– They are mostly small and nocturnal. (lemurs)

These are the tarsiers. Their physical appearance has changed little since their appearance 40 MYA.

12.6 Primate Evolution

– They are subdivided into the New World monkeys, Old World monkeys, and hominoids.

– Anthropoids are humanlike primates.

12.6 Primate Evolution

– New world monkeys are native to the Americas.–Live in trees–Have grasping tails

12.6 Primate Evolution

– Old world monkeys are native to Africa.– spend some time in trees, but spend much of the time foraging on the ground

- They have larger brains and can grasp things better.

12.6 Primate Evolution

- Homonoids are divided into hominids, great apes, and lesser apes.

– Homonids include living and extinct humans.

12.6 Primate Evolution

• Homonids walk upright, have longer lower limbs, opposable thumbs, and large brains

• Include all species in the human

lineage, both modern and extinct.

• The skeletal changes required

to walk upright can be seen in

intermediate fossils between

homonoids.

12.6 Primate Evolution

• Bipedal means walking on two legs.• Walking upright has

important adaptiveadvantages.– foraging– carrying infants and food– using tools

12.6 Primate Evolution

There are many fossils of extinct hominids.

• Most hominids are either the genus Australopithecus or Homo.

• Australopithecines were a successful genus.• The Homo genus first evolved 2.4 million years ago.

12.6 Primate Evolution

Modern humans arose about 100,000 years ago.

• Homo sapiens fossils date to 100,000 years ago in Ethopia.• Human evolution is influenced by a tool-based culture.• There is a trend toward increased brain size in hominids.

Australopithecusafarensis

Homo habilis Homo neanderthalensis

Homo sapiens