Evolution
Natural selection and the history of life.
Evolution
Genetic Drift Explained: Chance, Bottlenecks and Founder Effects
How random sampling changes allele frequencies in small populations, with bottleneck and founder effect examples and a size table.
EvolutionHow Natural Selection Works: Variation, Fitness and Adaptation
Natural selection explained: four requirements, directional, stabilizing and disruptive modes, and examples from finches and bacteria.