Size, Scaling, and the Evolution of Complex Life Cycles

Abstract

J.T. Bonner (1965) noted that the ultimate description of an organism is that of the life cycle. An organism is not the static representation of the adult we associate with taxonomic characterizations and most ecological theory, but the dynamic unfolding of the genome over ontogeny, and the consequent succession of life history stages or forms. The life cycle, of course, is also the fundamental unit of demographic analyses, and therefore a focus for considerations of ecological processes and their manifestation in evolutionary change. As Istock (1984) put it, every inference we make about the evolutionary process has some equivalent rendering within this demographic framework. Because the life cycle assumes a central position in the structure of biology, it is useful to order patterns in life cycle organization, and to ask what processes have shaped these patterns.