Understand that selection pressures acting on the gene pool change allele frequencies in the population, including:

- stabilising selection maintaining continuity in a population
- disruptive selection leading to changes or speciation.

Understand that sometimes changes in allele frequencies can be the result of chance and not selection, including genetic drift.

Understand that allele frequencies can be influenced by:

- population bottlenecks
- founder effect.

Understand how the Hardy-Weinberg equation can be used to monitor changes in the allele frequencies in a population.