Table 1.

Invasion criteria for a mutant allele. The quantity ΔS = S* − S is the entropy differential, with S and S* the entropy of the incumbent and the variant type, respectively. The quantity N denotes population size

Ecological constraints	Demographic condition	Selection outcome
(I) Constant but limited resource condition	ΔS > 0	Mutant invades almost surely (a.s.).
	ΔS < 0	Mutant becomes extinct a.s.
(II) Variable resource condition
(a) Large population size	ΔS < 0	Mutant invades a.s.
	ΔS > 0	Mutant becomes extinct a.s.
(b) Small population size	ΔS > 0	Mutant invades with a probability increasing with N.
	ΔS > 0	Mutant becomes extinct with a probability increasing with N.