© 1968 by The Society for Integrative and Comparative Biology
Animal Nutrition in Relation to Secondary Production
Department of Biology, Marquette University Milwaukee, Wisconsin 53233
The constant need to replenish dwindling energy resources compels the animal's day-to-day attack upon its food supply. Of the energy taken in through its food the animal loses a large percentage as non-productive energy while only a small fraction goes into the production of high-energy chemical compounds, some of which are retained as growth and the remainder discarded back to the environment. The non-productive energy is lost as wastes eliminated from the body, as respiration of symbionts and host, and as frictional heat. Energy flow through the individual organism is represented in a flow diagram which may serve as a model for relating future investigations. Several methods for evaluating the intake of food in natural populations are given, and factors which influence food-intake and feeding are discussed.
Energy flow through natural communities presents complex analytical problems because of the diversity and nutritional flexibility of the consumer species, factors important in maintaining community stability. For all the complexity, however, there appears to be a common pattern discernible in the trophic organization of different communities. A new model for representing energy flow through communities is presented and illustrated with the common pattern of community trophic organization.