Earth Science

Life on Earth

Human Evolution

Study Tip
Chimpanzees are humans’ closest relatives, which is why they resemble humans so greatly.

Human Evolution

Humans evolved during the later Cenozoic.

  • Primate ancestors: Humans evolved from primates, and apes and humans have a primate common ancestor
  • About 7 million years ago, chimpanzees and humans shared their last common ancestor
  • Hominids
  • Animals of the genus Ardipithecus, living roughly 4 to 6 million  years ago, had brains roughly the size of a female chimp
  • Although they lived in trees, they were bipedal
  • Standing on two feet allows an organism to see and also to use  its hands and arms for hunting
  • Homo: The genus Homo appeared about 2.5 million years ago
  • Humans developed the first stone tools
  • Fossils of these animals show a much more human-like body structure, which allowed them to travel long distances to hunt
  • Cultures begin and evolve
  • Homo sapiens: originated about 200,000 years ago in Africa
  • The ice ages allowed humans to migrate.
  • During the ice ages, water was frozen in glaciers and so land bridges such as the Bering Strait allowed humans to walk from the old world to the new world.
Study Tip
Chimpanzees are humans’ closest relatives, which is why they resemble humans so greatly.
Human ancestor
Australopithecus afarensis is a
human ancestor that lived about 3 million years ago.
Stone figurines
Stone figurines likely indicate a spiritual life.
Concept Check
  • Why did the evolution of bipedalism advance human evolution?
  • Draw a timeline of human ancestors including the name of the ancestor and the time that it lived.
  • What makes Homo sapiens different from Homo erectus?