MATHEMATICAL-MODEL ALLOWING THE COEXISTENCE OF CLOSELY-RELATED COMPETITORS AT THE INITIAL-STAGE OF EVOLUTION

The mathematical model presented here aims to elucidate the essential mechanisms of coexistence of species, especially those of closely rela ted forms, as a result of competition in the same environment. It desc ribes a system where the fate of the competitors or mutants is observe d at the initial stage of evolution. The model encompasses both the ex ternal variables and the internal state of the competitors, which diff er only in one of the metabolic rate constants. Results of simulations , even with the simplified form of the model, show that stable coexist ence of closely related forms in a uniform environment is possible. In addition, the model allows the analysis of the limitations on the lev el of differences and similarities among the competitors for achieving a state of coexistence. The essential mechanisms for the coexistence of closely related competitors are proposed to be the involvement of t he metabolic network in allowing the same growth rate of competitors w hich have different internal states, and the interplay between the int ernal states of the competitors and the external variables of their en vironment.