Abstract :
Presented is a simple model, based on computer simulations, of a population colonizing an adjacent habitat with different living conditions. Members of the population are characterized (apart from their positions on the lattice) by a single feature—a qualitative trait (phenotype). Its agreement with the optimum, determining the external conditions, relates to the survival probability. The process is influenced by three factors—selection pressure, fecundity, gene flow and mutation rate. The last is less important and only a combination of the first three factors determines whether an expansion is successful or not.