In Darwin's natural selection, which process leads to advantageous traits becoming more common in a population?

• A. Heritable traits that increase survival and reproduction
• B. Genetic drift randomizes trait frequencies
• C. Cultural transmission drives trait adoption
• D. Mutation without selection occurs

Answer: (A)

The key idea is that advantageous traits spread because they are heritable and boost an organism’s chances of surviving and reproducing. In Darwin’s natural selection, variation exists among individuals; those with traits that improve fitness leave more offspring, and since these traits are inherited, their frequency increases in the next generation and continues to rise over many generations. This differential reproductive success is what drives the evolutionary increase of beneficial traits.

Genetic drift could change trait frequencies by chance rather than because of their adaptive value. Cultural transmission involves the spread of learned behaviors rather than biological inheritance, so it isn’t the mechanism by which biological traits become more common. Mutation introduces new variation, but without selection to favor certain traits, those mutations don’t systematically become more common.