Biological Bases of Behavior Practice Test 2026 - Free Practice Questions and Study Guide

Natural selection is the process by which individuals with inherited traits that give them a survival or reproductive advantage are more likely to survive, reproduce, and pass those traits to their offspring. Over many generations, this differential success shifts which traits are common in a population, leading to adaptation to the environment. For example, if a certain trait helps individuals avoid predators or obtain more food, those individuals will leave more offspring, increasing the trait’s frequency in the gene pool.

Genetic drift is random change in trait frequencies, not driven by how advantageous the traits are. Mutation introduces new genetic variation, but it isn’t by itself a mechanism of differential survival. Migration changes allele frequencies by moving genes between populations, not by sorting existing variation based on fitness.