The action of the environment, as opposed to the actions of man, on individual organisms such that those possessing genotypes better suited to the environment will survive and reproduce more successfully than those with less favourable genotypes, which will eventually die out. By this process the characteristics of a population will change according to the nature of the environmental pressures acting on them. Over a number of generations the population may diverge into a number of distinct groups each adapted to a particular microenvironment. This process will be hastened if there are barriers to gene flow between the groups (see reproductive isolation). The concept of natural selection is the cornerstone in Darwin's theory of evolution (see Darwinism). |
