Genetic evidence sheds considerable light on the origins of the hominid lineage. An increasing body of fossil data helps us to understand where and when hominids came into existence. The first signs of hominid evolution are the morphological changes associated with bipedality, a locomotor pattern that offered fitness, advantages in a new environment. However, other behaviors remained similar to those of nonhuman primates. Dramatic progress came with the evolution of Homo erectus, who exhibited more "human" morphology and life ways. Thus, behavioral, fossil and artifact data couple to give us a glimpse into our evolutionary past.

The molecular clock is a method which determines how long ago a certain ancestor diverged into a new species. Up until the 1960's people believed that humans came into existence twenty million years ago, but Alan Wilson and Vincent Sarich came up with an idea to determine how closely related certain animals...