Why is the important for a paleoanthropologist to know about all primate?

Anthropology is the scientific study of the origin, the behavior, and the physical, social, and cultural development of humans.

Paleoanthropology is the study of extinct members of the genus Homo Sapiens.

As Homo Sapiens and other primates are closely related and have a common ancestor it is necessary for paleoanthropologists to be familiar with the evolution of existing and extinct primates.