Introduction
Body size is an important factor in many ecological interactions. For example, the rate at which an animal loses heat to the environment is determined in part by size. Specifically, heat loss is a function of surface area whereas heat production is proportional to the volume of the animal. Surface area increases as the square of the linear dimension; volume increases as the cube of the animal’s linear dimension. As a result, large organisms have a large volume relative to the surface area. Allometry, meaning different measures, is the relative scaling of different features of an organism. Figure 16.14 shows the relationship between surface area and heat loss.
Learning Goals
After reading your text and completing this exercise, you should be able to:
- Understand the phenomenon of allometry.
- Understand the difference between positive and negative allometry.
Figure 16.14 Surface area, volume, and heat loss. The allometric relationship between surface area, volume, and heat loss. Heat is produced as a function of the mass of the organism (which is related to its volume). Heat is lost as a function of surface area. The surface area of a small sphere is larger compared to its volume than that of a large sphere.