Which of the following species is classified as a hominin?

The classification of species as hominins is based on their evolutionary relationship to modern humans. Hominins are part of the subfamily Homininae and include modern humans and their direct ancestors after the split from the common ancestor with chimpanzees (the genera Pan).

Australopithecus falls under this category as it represents an early group of hominins that lived several million years ago. They are significant in the study of human evolution as they exhibit characteristics that show a transition from arboreal to bipedal locomotion and other traits that eventually led to the development of the genus Homo, which includes modern humans.

In contrast, the other species listed are not classified as hominins. Pan troglodytes (chimpanzees) and Gorilla gorilla (gorillas) are both classified under the family Hominidae but are situated in separate genera. Canis lupus (the gray wolf) belongs to a completely different family, Canidae, and thus is not related to the evolutionary lineage of humans. This clear distinction emphasizes why Australopithecus is recognized as a hominin, highlighting its place within human evolution.