Which statement about sexual selection best describes its role in evolution?

Which statement about sexual selection best describes its role in evolution?

• A. They can spread even if they reduce survival.
• B. They always increase survival.
• C. They only affect genetic drift.
• D. They have no effect on populations.

Answer: (A)

Sexual selection focuses on traits that boost mating success rather than survival. A trait can become common if it helps an individual attract mates and produce more offspring, even if it reduces survival. In evolution, fitness equals reproductive success plus survival, so a trait that increases the number of offspring can spread despite higher costs like predation or energy use. That’s why traits such as elaborate plumage or courtship displays can spread even when they shorten lifespan. The other ideas miss the core idea: sexual selection can change allele frequencies by enhancing mating success, not just by affecting survival, and it clearly has population-level effects.