Fellows lecture: Mary Jane West-Eberhard

Fellows lecture: Mary Jane West-Eberhard, Smithsonian Tropical Research Institute, Alternative developmental pathways and why they are so important in behavior and evolution. Sunday 8:45 -- 9:45 am

Abstract:

Understanding the origin of complexity and diversity in nature boils down to understanding the developmental organization of variation in phenotypes, or what we call the “traits” of organisms, and how that variation relates to natural selection and evolution. Phenotypic traits, including behavioral ones, are products of branching pathways during development. Every branch is response of a condition-sensitive organism to some new input, whether genomic or environmental; and the product of a particular branch is a modular aspect of the phenotype – a somewhat unitary trait. The alternative tactics of behavior and morphology so familiar to ethologists offer extreme examples of branching developmental pathways and how they structure development and the action of natural selection. By looking at how polyphenisms are organized it is possible to see why immediate behavioral responses are expected to take the lead in the evolution of behavioral complexity as well as the role of behavior in the evolution of physiological and morphological specialization. Organization by switch points, as in polyphenisms, also explains the interchangeability of genetic and environmental control of development, and provides concrete reasons to reject old dichotomies like nature vs nurture and instinct vs learning in discussions of animal behavior .