Final answer:
Sexual dimorphism is the term that describes when males and females of a population exhibit different physical traits or behaviors, often due to sexual selection.
Step-by-step explanation:
The trait where males and females of a population display differences in appearance or behavior is known as sexual dimorphism. This phenomenon arises due to sexual selection, where one sex typically has more reproductive success than the other. For instance, male peacocks have elaborate tail feathers to attract female mates, showcasing sexual dimorphism where physical traits are conspicuously different between the sexes. Sexual selection leads to such differences because it puts varying selective pressures on males and females.