7.4 Population Genetics

Explain how random occurrences affect the genetic makeup of a population.

• Evolution is also driven by random occurrences.
  • i. Mutation is a random process that adds new genetic variation t o a population.
  • ii. Genetic drift is a change in allele frequencies attributable to a nons elective process occurring in small populations. iii.The bottleneck effect is a type of genetic drift that occur s when a population size is reduced to a small number of individuals for at least one generation. iv.The founder effect is a type of genetic drift that occur s when a population is separated from other members of the population. The frequency of genes and traits will shift based on the genes in this new founder population.
  • v. Migration can result in gene flow (the addition or remov al of alleles from a population).

Describe the role of random processes in the evolution of specific populations.

• Random processes can lead to changes in allele frequencies in a population.
  • i. Mutations result in genetic variation, which provides phenotypes on which natural selection acts.
  • ii. Genetic drift can allow a small population to diverge from other populations of the same species.
  • iii. Gene flow between two populations prevents them from diverging into separate species.

Describe the change in the genetic makeup of a population over time.

• Changes in allele frequencies provide evidence for the occurrence of evolution in a population.