Human evolution, or anthropogenesis, is the origin and evolution of Homo sapiens as a distinct species from other hominids, great apes and placental mammals. The study of human evolution encompasses many scientific disciplines, including physical anthropology, primatology, archaeology, linguistics and genetics.The term "human" in the context of human evolution refers to the genus Homo, but studies of human evolution usually include other hominids, such as the Australopithecines, from which the genus Homo had diverged by about 2.3 to 2.4 million years ago in Africa.Scientists have estimated that humans branched off from their common ancestor with chimpanzees about 5–7 million years ago. Several species and subspecies of Homo evolved and are now extinct. These include Homo erectus, which inhabited Asia, and Homo sapiens neanderthalensis, which inhabited Europe. Archaic Homo sapiens evolved between 400,000 and 250,000 years ago.The dominant view among scientists concerning the origin of anatomically modern humans is the "Out of Africa" or recent African origin hypothesis,which argues that Homo sapiens arose in Africa and migrated out of the continent around 50,000 to 100,000 years ago, replacing populations of Homo erectus in Asia and Homo neanderthalensis in Europe. Scientists supporting the alternative multiregional hypothesis argue that Homo sapiens evolved as geographically separate but interbreeding populations stemming from a worldwide migration of Homo erectus out of Africa nearly 2.5 million years ago.
Evolution of the great apes
The evolutionary history of the primate can be traced back 65 million years, as one of the oldest of all surviving placental mammal groups. The oldest known primate-like mammal species, the Pleciadapis, come from North America, but they were widespread in Eurasia and Africa during the tropical conditions of the Paleocene.
Notharctus.
With the beginning of modern climates, marked by the formation of the first Antarctic ice in the early Oligocene around 30 million years ago. A primate from this time was Northacus. Fossil evidence found in Germany in the 1980s was determined to be about 16.5 million years old, some 1.5 million years older than similar species from East Africa and challenging the original theory regarding human ancestry originating on the African continent.David Begun says that these primates flourished in Eurasia and that the lineage leading to the African apes and humans including Dryopithecus migrated south from Europe or Western Asia into Africa. The surviving tropical population, which is seen most completely in the upper Eocene and lowermost Oligocene fossil beds of the Fayum depression southwest of Cairo, gave rise to all living primates lemurse of Madagascar, lorises of Southeast Asia, galagose or "bush babies" of Africa, and the antropoides; platyrrhines or New World monkeys, and catarrhines or Old World monkeys and the great apes and humans.
The earliest known catarrhine is kemoyapithecus from uppermost Oligocene at Eragaleit in the northern Kenya Rift Valley, dated to 24 million years ago. Its ancestry is generally thought to be species related to Propleopithacus, and parapithecus from the Fayum, at around 35 million years ago.In 2010, Saadanius was described as a close relative of the last common ancestor of the crown catarrhines, and tentatively dated to 29–28 million years ago, helping to fill an 11-million-year gap in the fossil record.In the early Miocene, about 22 million years ago, the many kinds of arboreally adapted primitive catarrhines from East Africa suggest a long history of prior diversification. Fossils at 20 million years ago include fragments attributed to Victoriapithacus, the earliest Old World Monkey. Among the genera thought to be in the ape lineage leading up to 13 million years ago are Proconsul, Rangwapithacus, Dendropithacus, Limnopithecus, Nacholapithacus, Equatorius, Nyanzapithecus, Afropithacus, Heliopithecus, and Kynyapithecus, all from East Africa. The presence of other generalized non-cercopithecids of middle Miocene age from sites far distant Otavipithecus from cave deposits in Namibia, and Pierolapithacus and from France, Spain and Austria is evidence of a wide diversity of forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the early and middle Miocene. The youngest of the Miocene hominoids, Dryopithecus Oreopithacus, is from 9 million year old coal beds in Italy.Molecular evidence indicates that the lineage of gibbons became distinct from Great Apes between 18 and 12 million years ago, and that of Orungutans (subfamily Ponginae) became distinct from the other Great Apes at about 12 million years; there are no fossils that clearly document the ancestry of gibbons, which may have originated in a so-far-unknown South East Asian hominoid population, but fossil proto-orangutans may be represented by from India and Griphopithacus from Turkey, dated to around 10 million years ago.
