Developmental processes and evolutionary diversity: some factors underlying form in primates

Abstract

Developmental biologists have shown, through experimental studies of embryos of a few species (especially the chick), that a small number of basic mechanisms underly the structural pattern of higher vertebrate limbs. Evolutionary biologists have shown, through morphometric studies of adults of many species (many mammals especially primates), that a small number of underlying factors are descriptive of the differences between the myriad of adult forms that exist through the process of evolution. In both areas very recent embryological experiments and morphometric observations point to the existence of yet further mechanisms and factors respectively. It is possible (a) that findings of the one type provide information predictive for the other and vice versa, and (b) that, as a result, a new conjunction is appearing between ontogenetic studies of changes in individuals within single species and phylogenetic investigations of differences between adults of many species within a family, an order, or even a class.