Blue-footed boobies have (unsurprisingly) blue, webbed feet. These colorful limbs help males attract females for mating. However, these feet also make boobies comically clumsy when they walk on land. What does this tell you about adaptations and natural selection? These feet are not an adaptation because it does not help the boobies to survive. Sexual selection is not a type of natural selection. Natural selection can allow adaptations to evolve, even if the characteristic was never in a population's gene pool. An adaptation may be helpful in certain cases, but it can also be harmful in other cases.