What is sexual selection?

 Sexual selection is a type of natural selection and a mechanism of evolution where individuals compete for access to mates and fertilization. However, a difference I found to easily distinguish the two is that natural selection favors traits that improve survival, but sexual selection focuses on traits that enhance the chances of mating. This concept explains how traits that normally might be disadvantageous -- such as bright feathers in birds -- can still be seen within a species. 

    There are two types of sexual selection: intersexual and intrasexual. Intersexual selection occurs when one sex competes to be chosen by the opposite sex for mating. An example of this can be seen in peacocks. Male peacocks have large and colorful tails, and these tails are seen as a sign of good health and genetic fitness, meaning the better the tails, the more likely they are to be chosen by females. 

    Intrasexual selection occurs when one sex competes directly with each other to access mates. This is typically in males, while intersexual selection is typically in females. In elephant seals, larger body size or greater strength helps males compete with the other males. The more dominant male typically wins, so they will have more opportunities to mate. 

    Surprisingly, in many species, males are often the focus of sexual selection. This is likely because females have to invest more energy into reproduction and parental care, so males have more free energy to spend by reproducing with multiple females. Males evolve more flashy traits or exhibit aggressive behaviors to either attract mates or fight against the competition.