Advances in fossil studies relating to the origin of Homo sapiens have strengthened the hypothesis that our direct ancestors originated on the African continent. Most researchers also agree that the time when prehumans diverged from the last common ancestor was in the early part of the Late Miocene epoch.

Focus must now shift from determining the times and places of hominid origins to clarifying hominid evolutionary problems, such as the selective factors and acquisition processes of hominid bipedalism. In March of 2003, researchers from Africa, Europe, Japan and the United States...