The first person to initially discover the method of selective breeding was Charles Darwin. His ideas are shown in the book the Origin Of Species. This produced the introduction of the theory of natural selection. Selctive breeding is the process of breeding animals in ways that are beneficial to humans, it is often not beneficial to the life of the animal. However, there are many desireable results of selective breeding high crop yields, resistance to disease, high growth rate and many other phenotypical characteristics that will benefit the organism and species in the long term.

http://www.fao.org/docrep/field/009/v8720e/V8720E25.gif
http://www.fao.org/docrep/field/009/v8720e/V8720E25.gif