What is required for evolution?

• A. Genetic drift alone
• B. Mutation only
• C. Overproduction, competition, and variation
• D. Migration only

Answer: (C)

Evolution happens when heritable differences exist and those differences affect which individuals survive and reproduce. Overproduction means more offspring are produced than the environment can support, so there is a struggle for resources. Variation among individuals provides different traits for natural selection to act on. If individuals with certain traits leave more offspring, those traits become more common over generations, changing the population. This combination—having more offspring than can survive, variation in traits, and differential reproduction—is what drives evolution. While mutation, genetic drift, or migration can influence patterns of evolution, they don’t by themselves guarantee evolution without the variation and the pressure of competition and differential success. That’s why the option that includes overproduction, competition, and variation is the best answer.