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Human evolution as a scientific field has a long and sometimes controversial history, however, since the mid- 1990s, there has been a remarkable convergence of views about how humans have evolved. This convergence includes paleoanthropologists, geneticists, and molecular biologists and is the subject of books such as Steve Olson's Mapping Human History ( 2002). This modern synthesis is also remarkable for its specificity. For example, there is strong scientific evidence supporting these conclusions:- around 2 to 2.5 million years ago, the genus Homo first appeared; (see, for example Cradle of Humankind)
- about 7,500 generations have passed since the appearance of modern humans;
- every person alive today is descended from a relatively small group of individuals living in Africa sometime between 100,000 and 200,000 years ago;
- mitochondrial Eve lived about 150,000 years ago;
- Y-chromosomal Adam lived between 35,000 and 90,000 years ago.
The role of language in the story of human evolution remains largely a matter of speculation, but recent discoveries about the FOXP2 gene, "the first gene known to be involved in the development of speech and language"¹, suggest new lines of inquiry and raise hopes about progress in understanding the origins of speech and language.
1 The Homo genus
Anthropologists generally recognize three speciesThis article discusses biological species. Also see combinatorial species for the mathematical meaning of the term. Species is also a movie by Roger Donaldson. In English "species" is both singular and plural. The word " specie" is unrelated and is used t of Homo:
- Homo habilisHomo habilis ("handy man") is a species of the genus Homo which lived from approximately 2. 5 million to 2. 0 million years ago. The definition of this species goes back to Louis Leakey who found fossils in Tanzania, East Africa, in 1964. Homo habilis is, from about 2.4 to 1.5 million years ago (MYA)
- Homo erectusHomo erectus ("upright man") is a hominid species that is believed to be an ancestor of modern humans. The species is found from the middle Pleistocene onwards. It had fairly modern human features, with a larger cranial capacity than that of Homo habilis', from about 1.8 (including ergasterHomo ergaster ("workman man") is an extinct hominid species (or subspecies, according to some authorities) which arose in Africa some 1. 9 million years ago. ergaster is sometimes categorized as a subspecies of Homo erectus''. It is currently in contentio) or from about 1.25 (excluding ergaster) to 0.07 MYA
- Homo sapiens, from about 200 thousand years ago (TYA) to the present
A number of other species have been proposed, including:
- Homo cepranensis
- Homo rudolfensisThe species Homo rudolfensis was originally proposed in 1986 by V. Alexeev for the specimen KNM ER 1470. Originally thought to be a member of the species Homo habilis much debate surrounded the fossil and its species assignment. It was thought that 2 mill
- Homo rhodesiensis (Rhodesian Man) from about 2.5 to about 1.75 MYA. Also proposed as Homo sapiens rhodesiensis
- Homo ergasterHomo ergaster ("workman man") is an extinct hominid species (or subspecies, according to some authorities) which arose in Africa some 1. 9 million years ago. ergaster is sometimes categorized as a subspecies of Homo erectus''. It is currently in contentio from about 1.8 to about 1.25 MYA. Also proposed as Homo erectus ergasterHomo erectus ("upright man") is a hominid species that is believed to be an ancestor of modern humans. The species is found from the middle Pleistocene onwards. It had fairly modern human features, with a larger cranial capacity than that of Homo habilis'
- Homo georgicus, about 1.8 MYA
- Homo antecessor from about 0.8 MYA
- Homo heidelbergensis (Heidelberg Man) from about 500 TYA to about 300 TYA. Also proposed as Homo sapiens heidelbergensis and Homo sapiens paleohungaricus.
- Homo neanderthalensis (Neanderthal Man) from about 250 to 30 TYA. Also proposed as Homo sapiens neanderthalensis.
- Homo sapiens idaltu from about 160 TYA (proposed subspecies).
- Homo floresiensis from about 12 TYA (announced 2004). Nicknamed hobbit for its small size.
There is not yet consensus as to which of these groups should count as separate species and which as subspecies of another species. In some cases this is due to the paucity of fossils, in others due to the very slight differences used to distinguish species in the Homo genus.
