Question

Consider the roles of different types of selective pressure.

Part A: Compare and contrast sexual selection, artificial selection, and natural selection.

Part B: Give examples of traits that may be favored in sexual selection, artificial selection, and natural selection. For each, explain if the trait would be favored by one type of selection but selected against by another type of selection.

Answer 1

Selection of a specific sex for a character is sexual selection.

Natural selection is selection of a trait because of an advantage to the surroundings.

Artificial selection is selection of a particular trait by humans due to some advantage or preference.

But all the three are selection processes resulting in changes in the frequency of the alleles in the population.

Part-B

In sexual selection, aggression is one trait that gets selected. Because the animal which can fight and win over other males will be able to mate and hence increase its numbers. Thats how selection of stronger males can result. Antlers in male are selected sexually because female mates with animals having huge antlers.

Natural selection selects traits that help an organism live successfully in a given environment. For example, dark brown coat for rabbits is the coat color that is selected by nature in the regions of volcanic eruption where the surroundings are dark colored. All types of selections can result in dark colored fur in animals if the surroundings are dark.

Artificial selection leads to selecting plants or animals with special agronomical traits such as a particular of the flower in plants or a specific fruit quality may be selected by humans.

Sexual selection can prefer animal with huge antlers because of which a male will be able to fight with more aggression. But such huge antlers may be heavy and it must be difficult to manage for the animal. But they are still present in certain male animals such as Alpine ibex. So, natural selection does not prefer huge horns.But sexual selection prefers huge horns or antlers.