Artificial Selection

This page is dedicated to explaining artificial selection.


Darwin proposed the mechanism of natural selection to explain the observable patterns of evolution. It is important to discuss the more familiar examples of selective breeding of domesticated plants and animals. Humans have modified other species over may generations by selecting and breeding individuals that possess desired traits, a process called artificial selection. As a result of artificial selection, crops, livestock, and pets now bear little resemblance to their wild ancestors.

A close examination of how humans have selectively bred and thus produced new species is essential to understanding evolution's impact on our lives.

Plants

Plants became a subject of artificial selection for aspiring horticulturalists, who select for different traits, from phenotypic variations like leaf size or flower sterility, and subsequently create, after enough generations, new species with new traits. An excellent example of this is wild mustard, which has been modified to create broccoli, cabbage, kale, cauliflower, and kohlrabi.

These different vegetables all originated from
one species of wild mustard after humans bred
selectively for different traits

The most helpful modifications of plants in recent history have evolved as a result of a more thorough understanding of genetics. Scientists modify plants' genes to select for resistance to pesticide, bugs, heat or water tolerance, production of food, and other variables.

This has revolutionized the food industry and farming, such that corn, for example now produces dramatically more food than 100 years ago.

This is how it works: farmers and scientists select a few individuals from the population that display resistance to heat, for example. Then only those individuals are allowed to reproduce so that the following generation contains entirely individuals that have a high resistance heat and drought.

Dogs

Man's best friend is an excellent example of artificial selection. From one common ancestor, Canis lupus (the gray wolf) there are now hundreds of different dog breeds of all shapes, sizes, and colors. The main point that should be understood is the astonishing power of domestication to not just change a species, but rapidly.

Descent of modern-day dogs

Connections

Artificial Selection represents what natural selection can do in the wild, as observed below by Darwin himself with the finches of the Galapagos Islands.

Darwin observed that the finches on the islands bore striking resemblance to their cousins in South America, yet had evolved into distinctly separate species, each specialized with different beak sizes and head shapes for eating different diets.

This is an example of natural selection in the wild, and by understanding artificial selection, an understanding of how such dramatic change is possible is obtained.