| Biologists find it convenient to atomize organisms, speaking of "parts" and "traits", even though organisms are integrated wholes. Over ontogeny, the development and growth of the various parts of complex morphologies must be coordinated if an individual is to function and interact with the environment in a manner which facilitates survival and reproduction. Similarly, evolutionary transformations which alter form must do so in a manner that preserves the functional integrity of morphological systems. The coordination, or lack thereof, among component parts of morphological systems can studied by using statistical measures of association such as covariance and correlation. The central concern of the studies described herein has been the development and elaboration of a variety of analytical tools for exploring and quantifying patterns of morphological trait association, with the ultimate goal of providing a quantitative framework for studying how patterns of phenotypic covariation evolve.;Three major topics are considered from the perspective of phenotypic covariance: (i) analyses of organismal shape; (ii) the quantification and analysis of growth processes; and (iii) the characterization and description of patterns of morphological integration. Each chapter outlines a new approach for addressing one of these areas and demonstrates the method with application to a variety of different data sets. Turtles of the sub-order Cryptodira serve as the focal group for many of these studies. Each of the methods is used in an analysis of epidermal scute patterns on the plastron, the ventral portion of the turtle shell. Additional studies are included which address some biomechanical and functional aspects of turtle shell morphology. |
