Making Behavioral and Phylogenetic Inferences from Hominid Fossils: Considering the Developmental Influence of Mechanical Forces

Fossils pose special problems for making phylogenetic and functional inferences about evolution. One reason is that bones have numerous functions and grow through a variety of processes, some of which are under strong genetic control, but many of which are highly influenced by external stimuli. Analyses of the angular kinetics, cross-sectional geometries, and microstructural properties of bones reveal information not only about the forces generated by habitual activities but also about osteogenic responses to such forces. Consequently, comparisons of osseous characters are at best an indirect and frequently misleading source of systematic information. By integrating functional and phylogenetic studies of the skeleton with analyses of how bones develop, we may find a useful solution to these problems.