Fastest Gene Frequency Change: Evolutionary Force

Correct Answer: Selection

From the notes: Selection changes gene frequency the fastest among all evolutionary forces, as it directly acts on phenotypes and can dramatically shift allele frequencies within a single generation.

Comparative Speed of Gene Frequency Change (from notes)

• Fastest: Selection ✔ — directly removes or favours alleles based on fitness
• Moderate: Migration — depends on proportion and gene frequency of migrants
• Moderate: Genetic drift — random in direction; significant only in small populations
• Slowest: Mutation — mutation rate is extremely low (~10⁻⁵ per locus per generation)

Fitness and Selection (from notes)

• Fitness (F) = 1 − S, where S is the coefficient of selection
• Example: If S = 0.1, then Fitness = 1 − 0.1 = 0.9
• Fitness = Adaptive value = Selective value = contribution of offspring to the next generation