ENVS200 Chapter Notes - Chapter 4: Directional Selection, Bank Vole, Antimicrobial Resistance
Document Summary
Changes in gene frequency within a population can occur through both natural selection and random processes such as genetic drift. In the previous sections of this chapter we have shown that phenotypic variation exists in natural populations, due to both environmental and genetic causes. Two scientists, george h. hardy and wilhelm weinberg, have shown independently that under a set of stringent conditions (e. g. , infinitely large populations, random mating, no selection), allelic variations in a gene will naturally be maintained within a population. This idea is called the hardy-weinberg principle, and serves as the starting point for a discussion of evolution. In this section, we will link our understanding of variation and heritability to two mechanisms of evolutionary change: natural selection and genetic drift. The basic concept of natural selection is that some heritable traits result in unequal fitness among individuals in a population.
