[Extremal principles and goal functions of biocoenotic systems]

A review considers known in the ecology two alternative principles of maximizing or minimizing the diversity-entropy of biological systems, and shows the inadequacy of both extremal principles in application to natural biocoenotic assemblages. A necessary condition for the multispecific system's existence is not extremization any of their parameters, but optimization of the relations of their parameters (including those that uniquely determine the value of species diversity). Thus, the goal function, which tends to minimize any biocoenotic system in the course of succession and evolution, is a deviation from this optimal ratio.