Question

It is quite common for species that are exposed to sexual selection to be sexually dimorphic. What best explains why the males of diverse species like the lion, elephant seal, and elk are so much larger than the females?

a) Large males are better able to defend their offspring; therefore, they make better mates.

b) Large males have superior predator avoidance skills; therefore, they make better mates.

c) Only large, robust males survive long enough to reach the age of sexual maturity.

d) In these populations, the males fight one another for the privilege of breeding; therefore, larger males are more likely to be successful.

Answer 1

The explanation for the larger size of males in certain species is that sexual selection favors males that are able to compete successfully for matings, often through direct competition or being selected by females, leading to sexual dimorphism.

Step-by-step explanation:

The best explanation for why males in species such as lions, elephant seals, and elk are larger than females is d) In these populations, the males fight one another for the privilege of breeding; therefore, larger males are more likely to be successful. This is a result of sexual selection, where there is significant variance in male reproductive success within a population. Larger, stronger, or more decorated males tend to win more matings, either by fighting off rivals or being chosen by females, leading to sexual dimorphism. Over time, these selection pressures result in the evolution of bigger body sizes and elaborate ornaments in males. Meanwhile, females may have more uniform reproductive success and thus often select the most desirable males based on these traits.

It's important to note that sexual selection sometimes leads to traits that are counterintuitive to survival. For example, the peacock's large tail is not practical and increases visibility to predators, but it is favored by females due to the handicap principle, which suggests that males able to survive with such traits must be very fit. This illustrates the powerful influence of sexual selection in shaping the physical characteristics of species.