This review begins by setting out the context and the scope of human evolution. Several classes of evidence,
morphological, molecular, and genetic, support a particularly close relationship between modern humans
and the species within the genus Pan, the chimpanzee. Thus human evolution is the study of the lineage, or
clade, comprising species more closely related to modern humans than to chimpanzees. Its stem species is
the so-called ‘common hominin ancestor’, and its only extant member is Homo sapiens. This clade contains
all the species more closely-related to modern humans than to any other living primate. Until recently, these
species were all subsumed into a family, Hominidae, but this group is now more usually recognised as a
tribe, the Hominini. The rest of the review sets out the formal nomenclature, history of discovery, and
information about the characteristic morphology, and its behavioural implications, of the species presently
included in the human clade. The taxa are considered within their assigned genera, beginning with the most
primitive and finishing with Homo. Within genera, species are presented in order of geological age. The
entries conclude with a list of the more important items of fossil evidence, and a summary of relevant
taxonomic issues.