We propose a model describing the colonization process of empty ecological niches. The members of the population are characterized by a single trait (phenotype). The fitness of an individual is measured as the difference between the value of its trait and the optimal phenotype characterizing the...

A model of a system of populations (metapopulation) is presented in which a population is characterized by a mean phenotype (or equivalently a continuous character) averaged over all individuals belonging to the population. The populations interact by exchanging genetic information (gene flow)...

We introduce a model of a large, sexual, population in which partners for reproduction are chosen randomly, without any bias. This large population is composed of two groups of local populations living in different environments and being in contact. We propose a dynamic equation describing, like...