An evolution theory in finite size systems

A new model of evolution is presented for finite size systems. Conditions u nder which a minority species can emerge, spread and stabilize to a macrosc opic size are studied. It is found that space organization is instrumental in addition to a qualitative advantage. Some peculiar topologies ensure the overcome of the initial majority species. However the probability of such local clusters is very small and depend strongly on the system size. A prob abilistic phase diagram is obtained for small sizes. It reduces to a trivia l situation in the thermodynamic limit, thus indicating the importance of d ealing with finite systems in evolution problems. Results are discussed wit h respect to both Darwin and punctuated equilibria theories.