The Measure of Things: Pattern, Process and Morphometry
Paul O’Higgins is Chair of Anatomy at the University of York, UK, and Head of the Centre for Anatomical and Human Sciences, Hull York Medical School. His principal interests concern the links between skeletal morphological variation, phylogeny, function and ontogeny. His earliest work concerned the post natal growth of the skull and spine in mice and apes and contributed to the development of an important new class of statistical and graphical methods for the analysis of form differences in biology, Geometric Morphometrics. A key feature of O’Higgins’ research has been the statistical analysis of structure in addressing the biological significance of skeletal variation. One of his most important contributions has been the publication of widely used software for the full three-dimensional modeling and analysis of shape variations using these techniques. His studies of craniofacial evolution have shown how growth variations contribute to craniofacial variations among adult primates. These have related remodeling, ontogenetic shape changes and phylogeny to each other and have provided important new insights into the ontogeny of differences among sexes, subspecies and species.
Abstract: What leads us to measure the form of things? In biology, the morphometrician’s concern is to understand how structures vary in form and how patterns of variation relate to the processes that generate or influence them, such as development, evolution or function. A sophisticated battery of approaches has grown up for analysis and with it a large literature addressing the pros and cons of diverse approaches. How and what we measure, the first step of any morphometric analysis has received less recent attention, despite the fact that it underpins the whole morphometric task. While morphometrics has a diversity of methods for measurement, the analysis of the form of a configuration of landmark coordinates is now a common approach. Thus, in geometric morphometrics sophisticated algorithms allow us to extend landmarks to curves and surfaces, and a robust statistical understanding of the shape space for Procrustes registered landmark configurations underpins subsequent analysis. However, beyond the choice of measurement method is the question of how to apply it, of what to measure. What do landmark configurations mean? What information do they bring to the analysis and to what extent do they allow us to link pattern to process? This lecture will consider these questions in the context of studies of form and function in the primate skeleton with the aim of clarifying the measure of things in relation to pattern, process and morphometry.
Professor O’Higgins is the recipient of the 2013 Rohlf Medal for Excellence in Morphometric Methods and Applications, which was established in 2006 to mark the 70th birthday of F. James Rohlf, Distinguished Professor of Ecology and Evolution and longtime Stony Brook University faculty member. The medal is presented every two years.