reproduction must be independent of genotypic influence. Since most aspects of reproduction are inextricably influenced by genotype, non-random reproduction must be considered the norm. Non-random, genotype-influenced reproduction causes natural selection to occur. Natural selection is a process in which individuals with genotypic traits of adaptive superiority are more likely to survive to reproduce while individuals that lack genotypic traits of adaptive superiority are less likely to survive to reproduce. Thus, natural selection is said to exert selection pressure on all populations in favor of individuals with the genotypic traits of adaptive superiority.
Because it is impossible for the gene pool of any population to meet all four conditions of stability as mandated by the Hardy-Weinberg Principle (especially with regard to the requirements of having no mutations and random reproduction), it can be said that the gene pool of a population can never be in complete equilibrium and, thus, that evolutionary change, based largely on natural selection and to a lesser extent on genetic drift, mutation pressure, and gene flow, must be a common part of the existence of all populations.
The Hardy-Weinberg Equilibrium can be expressed as an algebraic formula. The formula is useful in comparing the genotypic frequencies of one generation to another to determine if genetic equilibrium has been altered. For the consideration of the frequencies of two alleles, a binomial equation where p equals the frequency of the dominant allele and q equals the frequency of the
