Meeting Abstract

S11.1  Wednesday, Jan. 6  Introduction to the Symposium: Contemporary Approaches to the Study of the Evolution of Fish Body Plan and Fin Shape WALKER, J.A.; Univ. Southern Maine walker@maine.edu

The evolution of fish body shape is one of the central problems in vertebrate morphology. Because of the apparently obvious form-function mapping of fish body shape, comparisons of shape among fishes have been central to many recent studies in local adaptation, adaptive plasticity, competition, and evolutionary constraints. But comprehensive, well-tested models for body shape variation are wanting. The core of the problem is that fish body shape affects many, many functions, so asking “what is this body shape for” is a doomed approach, and that many different phenotype combinations can result in similar levels of performance. These problems are compounded by (1) the many other phenotypic traits that affect these functions and (2) the feedback across generations between selected traits and the genetic and developmental processes that build the body. No. 1 confounds attempts to build simple models of form-function mapping because of intertrait correlations, functional compensation or redundancy, and interaction effects. No. 2 suggests that any explanation of fish body shape diversity must take into account the genetic and developmental architecture of fish body shape. Explanations of form or variation in form, then, are complicated by the different levels of organization in biological design, the complexity of the causal mapping (or regulatory control) from lower to higher levels, and the feedback from higher to lower levels of organization. The speakers in this symposium were invited to specifically address the genetic, developmental, functional and ecological architecture of fish body shape and more generally address how their work facilitates the advancement of current models of the proximate and ultimate mechanisms regulating the development and evolution of fish body shape.