Final answer:
Sexual selection leads to the evolution of secondary sexual characteristics that enhance reproductive success in males and females, often resulting in sexual dimorphism. Males may develop elaborate adornments to attract females, while females tend to select mates that demonstrate genetic fitness
Step-by-step explanation:
The reproductive strategies of males and females lead to sexual selection, a special case of natural selection identified by Charles Darwin. Sexual selection is the process by which certain traits become more prevalent within a population due to differences in reproductive success between individuals.
For males, the pressure to successfully mate often results in the development of striking secondary sexual characteristics like colorful plumage or large body size. These traits, while potentially detrimental to survival (due to increased visibility to predators or other costs), may enhance males' chances to attract females or outcompete other males, hence ensuring greater reproductive success.
Females generally have different selective pressures. They usually have less variance in reproductive success and tend to be choosier about their mates. They opt for those who show signs of strong genetic fitness, which might be indicated by the very characteristics that males develop under sexual selection pressure.
Sexual dimorphism often results from the various strategies of sexual selection, with intersexual selection (mate choice) and intrasexual selection (competition among the same sex) contributing to the evolution of distinct differences between the sexes beyond just reproductive organs. In many cases, features such as the peacock's tail have become larger or more colorful in males due to these mechanisms despite their potential survival costs, an idea known as the handicap principle.