Humans are classified in the mammalian family Primates. In this arrangement, humans, along with our extinct close ancestors, and our nearest living relatives, the African apes, are sometimes placed together in the family Hominidae because of genetic similarities. Two-legged walking seems to be one of the earliest of the major hominine characteristics to have evolved. In the course of human evolution the size of the brain has more than tripled. The increase in brain size may be related to changes in hominine behavior (See figure 3). The third major trend in hominine development is the gradual decrease in the size of the face and teeth.

According to the Microsoft Encarta '98, the fossil evidence for direct ancestors of

The fossil evidence for human evolution begins with the australopithecines. All the australopithecines were clearly bipedal and therefore apparent hominines. In details of their teeth, jaws, and brain size, however, they modify enough among themselves to explain division into five species: Australopithecus anamensis, A. afarensis, A. africanus, A. robustus, and A. boisei. Homo are also divided in five different spices: Homo erectus, H. habilis, H. sapiens, and H. sapiens sapiens.

Homo erectus lived from about 1.8 million to 30,000 years ago. Until recently, Homo erectus was considered an evolutionary ancestor of modern humans, or Homo sapiens. Homo erectus had a larger brain than earlier hominines. Homo erectus was also a taller, with an evenly face and smaller tooth. Large differences in body size between males and females, characteristic of earlier hominine species, are less evident in Homo erectus specimens. Scientists believe this species lived in Africa between 2 million and 1.5 million years ago. H. habilis is the earliest known member of the genus Homo. H. habilis had a larger brain than australopithecines. Australopithecines had long arms and short legs, similar to the limbs of apes. Proportionally, H. habilis resembled modern humans with its limbs and small body size relative to its height. H. habilis had smaller molars teeth and a less raised face than earlier

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