Chapter 10

What is a hominid?

Hominids are defined by two obligate behaviors: bipedal locomotion and nonhoning chewing.

Why did hominids evolve from an apelike primate?

The Hominidae's origin is closely tied to the origins of bipedal locomotion. This form of movement may have provided early hominids with a more efficient means of exploiting patchy forests, freeing the hands for feeding in trees and on the ground.

Who were the first hominids?

The earliest fossil hominids were the pre-australopithecines, dating to 7-4 mya. These hominids lived in forests. The pre-australopithecines gave rise to the australopithecines, dating 4-1 mya.

What was the evolutionary fate of the first hominids?

The evolution of the australopithecine lineages resulted in generally increased robusticity of the chewing complex, no change in brain size, and eventual extiniction. The change in the chewing complex reflected an increasing emphasis on eating hard foods, especially plants. By 2.5 mya, at least on australopithecine lineage gave rise to the genus Homo. Having evolved from earlier australopithecines, at least two other australopithecine lineages, one in East Africa and one in South Africa, went extinct around 1 mya.