Sexual Selection as a Determinant of Certain Traits

Sexual Selection as a Determinant of Certain Traits

If you were a male would you rather have a beautiful, impressive, long tail that attracts a lot of women or would you rather have a shorter, less attractive tail that enables you to escape from predators more easily? Living out in the wild among many potential predators, a shorter tail would seem more logical since it would be a more useful trait than a good-looking one. Though the most logical choice, it is not always the case. In many species, traits that would normally be considered awkward or cumbersome are actually favorable. Hard to believe as it may be, these seemingly maladaptive traits can prove to be very useful to certain members of many different species as shown by Darwin’s Theory of Sexual Selection. They enhance the ability of the individual to obtain mates and are therefore very important in the reproductive and evolutionary success of many animals.

It is first necessary to understand the basics of Natural Selection before being able to show how Sexual Selection leads to extravagant traits. The main idea behind natural selection is that living organisms change and adapt in order to enhance their ability to survive and reproduce. Those animals that adapt will be more likely to survive and produce more offspring than other animals in the same environment that do not (Boyd and Silk 2000, p. 5), as maintained by Darwin’s second postulate. Phenotypes that are favored by Natural Selection include the ability to care for offspring, acquire resources, and avoid predators.

The correlation between Natural Selection and Sexual Selection is the next necessary step to understanding how Sexual Selection accounts for awkward traits. The later of the two can be considered a special category of natural selection. It involves selection for traits only concerned with increasing the probability of mating (Krebs and Davies, 1993, p. 89). It is expressed most strongly in the sex whose access to mates is most limited. In mammalian males, sexual selection tends to have a greater impact on behavior and morphology than does other forms of natural selection.

Due to the combination of females investing more in the care of the offspring and the one-to-one population sex ratio, males are usually the ones in competition for females. Male reproductive success also varies much more than that of the female.