Sexual selection, or non-random mating, is one of the five forces that can cause evolutionary change. Sexual selection can take the form of competition between members of the same sex (intrasexual selection) or selection of mates of the opposite sex (intersexual selection). Intrasexual selection typically involves conflicts between males, while intersexual selection most often involves female choice. Traits involved in sexual selection lead to sexual dimorphism, the difference between sexes beyond the sex characteristics. This simulation focuses on intersexual selection in the form of color brightness. Males in this fictional population exhibit variations in brightness, with brighter males more likely to have mating opportunities, but also more likely to be eaten by predators. For more, check out the Sexual Selection text and Sexual Selection Worksheet.