The body of this book is broadly restricted to an allometric analysis of the balanced growth equation and its extensions. This equation provides a convenient framework upon which many diverse relations may be organized. However, the validity of the individual relations is not dependent on the concept of energetic balance, and not all allometric relations can be arranged in that context. For example, larger animals are less sensitive to high-frequency sounds (Heffner & Heffner 1980). I am prepared to believe that this has ecological implications and should be mentioned but I see no place for it in the balanced growth equation. The interest an equation holds is in no way diminished (and is arguably increased), because it bears little relation to the central theme of the balanced growth equation.

This chapter briefly examines the role of body size in three areas: animal behavior, ecological economics, and evolution. In general, these areas rarely use body size as an independent variable in interspecific comparisons, and a consideration of these topics carries me further from my area of expertise. Consequently, the discussions below are briefer and more speculative than many earlier arguments. I hope points raised here will be sufficiently interesting that more capable workers will pursue them, if only to offer falsifications.

Animal behavior

All patterns of animal behavior exist within the range of possibilities defined by physiology and ecology. Since these scale with size, the range of behavior must also do so.