Human taxonomy

Human taxonomy is the classification of the human species (systematic name Homo sapiens, Latin: 'wise man') within zoological taxonomy. The systematic genus, Homo, is designed to include both anatomically modern humans and extinct varieties of archaic humans. Current humans have been designated as subspecies Homo sapiens sapiens, differentiated from the direct ancestor, Homo sapiens idaltu. Since the introduction of systematic names in the 18th century, knowledge of human evolution has increased drastically, and a number of intermediate taxa have been proposed in the 20th to early 21st century. The most widely accepted taxonomy groups takes the genus Homo as originating between two and three million years ago, divided into at least two species, archaic Homo erectus and modern Homo sapiens, with about a dozen further suggestions for species without universal recognition. The genus Homo is placed in the tribe Hominini alongside Pan (chimpanzees). The two genera are estimated to have diverged over an extended time of hybridization spanning roughly 10 to 6 million years ago, with possible admixture as late as 4 million years ago. A subtribe of uncertain validity, grouping archaic 'pre-human' or 'para-human' species younger than the Homo-Pan split is Australopithecina (proposed in 1939). A proposal by Wood and Richmond (2000) would introduce Hominina as a subtribe alongside Australopithecina, with Homo the only known genus within Hominina. Alternatively, following Cela-Conde and Ayala (2003), the 'pre-human' or 'proto-human' genera of Australopithecus, Ardipithecus, Praeanthropus, and possibly Sahelanthropus may be placed on equal footing alongside the genus Homo. An even more radical view rejects the division of Pan and Homo as separate genera, which based on the Principle of Priority would imply the re-classification of chimpanzees as Homo paniscus (or similar). Prior to the current scientific classification of humans, philosophers and scientists have made various attempts to classify humans. They offered definitions of the human being and schemes for classifying types of humans. Biologists once classified races as subspecies, but today anthropologists reject the concept of race and view humanity as an interrelated genetic continuum. Taxonomy of the hominins continues to evolve. Human taxonomy on one hand involves the placement of humans within the Taxonomy of the hominids (great apes), and on the other the division of archaic and modern humans into species and, if applicable, subspecies. Modern zoological taxonomy was developed by Carl Linnaeus during the 1730s to 1750s. He named the human species as Homo sapiens in 1758, as the only member species of the genus Homo, divided into several subspecies corresponding to the great races. The Latin noun homō (genitive hominis) means 'human being'. The systematic name Hominidae for the family of the great apes was introduced by John Edward Gray (1825). Gray also supplied Hominini as the name of the tribe including both chimpanzees (genus Pan) and humans (genus Homo). The discovery of the first extinct archaic human species from the fossil record dates to the mid 19th century, Homo neanderthalensis, classified in 1864. Since then, a number of other archaic species have been named, but there is no universal consensus as to their exact number. After the discovery of H. neanderthalensis, which even if 'archaic' is recognizable as clearly human, late 19th to early 20th century anthropology for a time was occupied with finding the supposedly 'missing link' between Homo and Pan. The 'Piltdown Man' hoax of 1912 was the fraudulent presentation of such a transitional species. Since the mid-20th century, knowledge of the development of Hominini has become much more detailed, and taxonomical terminology has been altered a number of times to reflect this. The introduction of Australopithecus as a third genus, alongside Homo and Pan, in the Hominini tribe is due to Raymond Dart (1925). Australopithecina as a subtribe containing Australopithecus as well as Paranthropus (Broom 1938) is a proposal by Gregory & Hellman (1939). More recently proposed additions to the Australopithecina subtribe include Ardipithecus (1995) and Kenyanthropus (2001). The position of Sahelanthropus (2002) relative to Australopithecina within Hominini is unclear. Cela-Conde and Ayala (2003) propose the recognition of Australopithecus, Ardipithecus, Praeanthropus, and Sahelanthropus (the latter incertae sedis) as separate genera.