Final answer:
Intrasexual competition leads to evolutionary traits like body size dimorphism, canine size dimorphism, and sperm competition as males of many species compete for mating opportunities, leading to varied reproductive success.
Step-by-step explanation:
Intrasexual competition, such as male-male competition for access to mating opportunities, can lead to several biological phenomena. These include body size dimorphism, where there are differences in size between males and females of the same species, canine size dimorphism, where there are differences in canine tooth size typically used for fighting over mates, and sperm competition, which involves competition at the gametic level after mating has occurred. Examples of these phenomena include male lions battling for mating rights, where typically the strongest and most dominant males will mate, leading to differences in body and canine size. Similarly, sperm competition can be seen across various species where multiple males may mate with the same female, and the most competitive sperm succeed in fertilization.