Human Evolution

The evolutionary tree shows the relationship between humans and the great apes. All great apes, including baboons, gibbons, orangutans, gorillas, chimpanzees, humans, and human ancestors, belong in the superfamily Hominoidea. Of these great apes, all but baboons and gibbons belong in the family Hominidae. Gorillas, chimpanzees, humans, and human ancestors belong in the subfamily Homininae. Humans and their direct ancestors belong in the tribe Hominini.
Hominin phylogeny. This chart shows evolutionary relationship among Hominins and hypothesized relation to modern humans. (*still debated phylogeny position). Source: OpenStax Biology 2e

OpenStax Biology 2e

The family Hominidae of order Primates includes the hominoids: the great apes and humans. Evidence from the fossil record and from a comparison of human and chimpanzee DNA suggests that humans and chimpanzees diverged from a common hominoid ancestor approximately six million years ago. Several species evolved from the evolutionary branch that includes humans, although our species is the only surviving member. The term hominin is used to refer to those species that evolved after this split of the primate line, thereby designating species that are more closely related to humans than to chimpanzees. A number of marker features differentiate humans from the other hominoids, including bipedalism or upright posture, increase in the size of the brain, and a fully opposable thumb that can touch the little finger. Bipedal hominins include several groups that were probably part of the modern human lineage—AustralopithecusHomo habilis, and Homo erectus—and several non-ancestral groups that can be considered “cousins” of modern humans, such as Neanderthals and Denisovans.

Determining the true lines of descent in hominins is difficult. In years past, when relatively few hominin fossils had been recovered, some scientists believed that considering them in order, from oldest to youngest, would demonstrate the course of evolution from early hominins to modern humans. In the past several years, however, many new fossils have been found, and it is clear that there was often more than one species alive at any one time and that many of the fossils found (and species named) represent hominin species that died out and are not ancestral to modern humans.


Clark, M., Douglas, M., Choi, J. Biology 2e. Houston, Texas: OpenStax. Access for free at:


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