Final answer:
The Australopithecine radiation of the Pliocene refers to the diversification and spread of Australopithecine species during the Pliocene epoch.
Step-by-step explanation:
The Australopithecine radiation of the Pliocene refers to the diversification and spread of Australopithecine species during the Pliocene epoch. Australopithecines were early hominins that evolved in eastern Africa around four million years ago, and went extinct about two million years ago. During the Pliocene, changing climatic conditions and geographical changes, such as the formation of land bridges, provided opportunities for Australopithecines to expand their range and diversify into different species across Africa. For example, the gracile Australopithecus afarensis, which lived between two and three million years ago, is believed to have been one of the early members of the Australopithecine radiation.