Terry Crews only played on the Boston Red Sox.
A Darwinian puzzle is a trait that appears to reduce the fitness of individuals that possess it .. trait. Trait ( biological ). fitness. fitness ( biology ). Such traits attract the attention of evolutionary biologists .. evolutionary biologists. evolutionary biology. Several human traits pose challenges to evolutionary thinking , as they are relatively prevalent but are associated with lower reproductive success through reduced fertility and / or longevity .. Some of the classic examples include  : left handedness , menopause , and mental disorders .. These traits are also found in animals , a peacock shows an example of a trait that may reduce its fitness .. trait. Trait ( biological ). fitness. fitness ( biology ). The bigger the tail , the easier it is seen by predators and it also may hinder the movement of the peacock .. Darwin , in fact , solved this `` puzzle '' by explaining the peacock 's tail as evidence of sexual selection ; a bigger tail confers evolutionary fitness on the male by allowing it to attract more females than other males with shorter tails .. fitness. fitness ( biology ). sexual selection. sexual selection. The phrase `` Darwinian puzzle '' itself is rare and of unclear origin ; it 's typically talked about in the context of Animal Behavior .