The phenomenon occurring when a population is founded by a small sample of the entire species, perhaps just a handful of individuals. Chance dictates that these founder members will be genetically unrepresentative of the species as a whole, and that the genetic make-up of the new population will differ markedly from the main species population. The founder effect thus increases the likelihood of evolutionary divergence from the main species, and eventually the formation of a new species. See peripatric speciation.