ABSTRACT
The interest in human classification and evolution has been so great that it has produced a bewildering quantity and variety of terms and theories. This chapter argues that the principal groups of the living primates are adaptive and that the characters by which they have been recognized are structures which are closely related to the behavior of the groups. Emphasis on behavior does give a way of evaluating structure, and this can be illustrated by comparing three pairs of taxa which have often been classed as subfamilies: Galaginae and Lorisinae, Cercopithecinae and Colobinae, Hylobatinae and Ponginae. The many structural-behavioral similarities of the Old World monkeys suggest that a single family, divided into two sub-families to express the differing visceral adaptation, is appropriate. The emphasis on behavior may be defended on theoretical grounds. If the direction of evolution is due primarily to natural selection, the taxa which are recognized today should be the ends of adaptive radiations.
