Final answer:
Selective breeding, or artificial selection, involves breeding animals or plants for specific traits. While it has positive aspects like improving certain desirable characteristics, it can also lead to health issues due to limited genetic diversity and the problems associated with inbreeding.
Step-by-step explanation:
Selective Breeding in Animals
Selective breeding, also known as artificial selection, is a process where humans choose specific animals to breed based on desired traits. This practice has been pivotal in developing various animal breeds, particularly in agriculture and pet ownership. However, it often comes with a cost to the animal's health. For example, the trend of breeding English bulldogs for certain physical traits has resulted in a high percentage of births requiring cesarean sections. The pursuit of aesthetic features like neotony can also lead to a reduction in genetic diversity, making animals more susceptible to hereditary health issues.
Breeders strive to avoid inbreeding as it can result in diversifying selection, which is counterproductive to maintaining the desired traits. Moreover, inbred populations can accumulate harmful genetic mutations. Consequently, responsible breeders practice selective mating to ensure the health and vitality of the animals' gene pool.
The importance of selective breeding can also be appreciated in the context of historical examples, such as Darwin's observations on finches, which illustrate how a single species can diversify into many through selective pressures. In domestication, the selection process has dramatically altered species, as evidenced in a study showing changes in crops like corn and peaches over 9,000 years of breeding.