Biology 1108 Human Origins & Evolution

Primate

an order of mammals, distinguished by a number of molecular and morphological features, including relatively large brains, nails rather than claws, front- facing eyes, and, in some species opposable thumbs

Hominin

A member of one of the many different species in the lineage that eventually resulted in humans after the split of that lineage from the one leading to chimpanzees about 7 million years ago

Ardi

A specimen of Ardipithecus ramidus, an early hominin, dating from about 4.4 million years ago.

Lucy

An unusually complete specimen of an early hominin fossil, Australopithecus afarensis, found in 1974 in Ethiopia and dating to 3.2 million years ago.

Bipedal

Habitually walking upright.

Neanderthal

Homo neanderthalensis, a species similar to humans, but with thicker bones and flatter heads; present in the fossil record 600,000–30,000 years ago.

Multiregional hypothesis

The idea that modern humans derive from the Homo ergaster populations that spread around the world starting 2 million years ago.

Out-of-Africa hypothesis

The idea that modern humans arose from Homo heidelbergensis descendants in Africa before dispersing beyond Africa around 60,000 years ago.

Mitochondrial DNA (mtDNA)

A small circle of DNA, about 17,000 base pairs long in humans, found in every mitochondrion.

Cro-Magnon

The first known population of Homo sapiens in Europe, named for the site in France where specimens were first described.

Ancient DNA

The analysis of DNA sequences from long-dead organisms.

Neoteny

The process in which the timing of development is altered so that a sexually mature organism retains the physical characteristics of the juvenile form.