A simple model of large scale organization in evolution

A mathematical model of interacting species filling ecological niches left by the extinction of others is introduced. Species organize themselves into genera of all sizes. The size of a genus on average grows Linearly with it s age, confirming a general relation between Age and Area proposed by Willi s. The ecology exhibits punctuated equilibrium. Analytic and numerical resu lts show that the probability distribution of genera sizes, genera lifetime s, and extinction event sizes are the same power law P(x) similar to 1/x(2) consistent with paleontological data.