Natural Selection

some populations are, or have been, very small and therefore mating is not always random. gene mutations also occur in populations. all of these factors will lead to changes in frequency of alleles of a particular gene in a population.
natural selection is one of the most important factors that can lead to a change in allele frequency. natural selection results from the differential fertility of organisms that,in turn, results from their genotype. the size of a population is limited by a number of environmental factors ie. animals compete for food and plants compete for space, water and access ...