Module 8 Population Genetics

4.8.1 page 5

Lesson Summary

When gene pool allele frequencies remain the same over time, the population is in Hardy Weinberg Equilibrium. Conditions needed for HWE are: a closed population, a large population, no net change in mutation rate, random mating, and no natural selection. If these conditions aren’t met, allele frequencies will change and by definition the population will evolve. Therefore, the conditions for evolution are: an open population (gene flow), a small population (genetic drift), change in mutation rate, non-random mating, and natural selection.

Glossary

population: organisms of a particular species in a particular place at a particular time

gene pool: a hypothetical construct consisting of all of the alleles from all of organisms of a particular population

frequency: #/total

gene flow : movement of alleles into or out of a population by immigration or emigration

micro-evolution: a change in the frequency of alleles in the gene pool

natural selection: process by which organisms with certain heritable traits survive, passing on their traits to the next generation; determined by the environmental conditions of the time 

Hardy Weinberg Principle: Allele frequencies in a population will remain the same over time as long as the population is large, there is no gene flow, there is no natural selection, there is no change in mutation rate, and there is no mate selection. If allele frequencies do change, it indicates micro-evolution is occurring in the population