| During the past decade, evolutionary biology, particularly research utilizing concepts of morphological function or adaptation, has come under increasing attack as non-scientific. The basis for this criticism is reviewed and analyzed, and it is concluded that there are fundamental problems with some aspects of evolutionary science; paleontologists have often not recognized the historical restrictions on causal explanations, functional morphologists have ignored biological limitations in overly reducing their explanatory mode to mechanical engineering, and a major analytic tool, allometric scaling, is an arbitrary technique for eliminating size-correlated variation, rather than a method for studying it.; Based on these conclusions, a new model for functional explanation in paleontology is presented, and the model is used to analyze data on the relationship between craniofacial morphology and diet in extant primates and Miocene hominoids. A series of measurements are taken on 253 specimens from 32 primate species. Partial correlation coefficients from a series of "causal model" multiple regression equations are used to select measurements that have a particular relationship to either phylogenetic, size, or dietary effects. These variables are then used to develop a series of "predictive model" regression equations that are used to infer the percentage of fruits, leaves, and insects in the diets of several Miocene hominoids. Proconsul africanus and Proconsul major may have been more folivorous than has been suggested recently by others, and Ramapithecus may have included a substantial frugivorous component in its diet. The results also bring into question a variety of additional assumptions concerning the relationship between statistical models and biological explanation. |
