. The earliest hominine remains possess canines that project slightly, but those of all later hominines show a marked reduction in size. Also, the chewing teeth, the premolars and molars, have decreased in size over time. Associated with these changes is a gradual reduction in the size of the face and jaws. In early hominines, the face was large and positioned in front of the braincase. As the teeth became smaller and the brain expanded, the face became smaller and its position changed. Thus, the relatively small face of modern humans is located below, rather than in front of, the large, expanded braincase. Evidence of immediate relatives of the human species begins about five million years ago with the Australopithecus genus and leads in to the primitive Homo genus to modern humans. The nature of the human’s evolution before that is uncertain, but scientists have hypothesized some ideas. What they do know is that between 7 and 20 million years ago, primitive apelike animals were widely distributed on the Snell 3African and later on the Eurasian continents. Although many fossil bones and teeth have been found, the way of life of these creatures, and their evolutionary relationships to the living apes and humans, remain matters of strong disagreement among scientists. One of these fossil apes, known as Sivapithecus, appears to share many features with the living Asian great ape and the orangutan, whose direct ancestor it may well be. None of these fossils, however, offers convincing evidence of being on the evolutionary line leading to the hominid family generally. But they do help paint a picture of what early human relatives could have been like. The convincing fossil evidence for human evolution begins with Australopithecus. Fossils of this genus have been discovered in a number of sites in eastern and southern Africa, and were first identified in South Africa in 1924. Earliest fossils show them existing about 3.9 million years ...
