Re: how is selective breeding similar to the evolutionary process and why?

Darwin claimed that he came to an understanding of natural selection (what we commonly call evolution) by analogy with artificial selection (or selective breeding). In fact, chapter one of On the Origin of Species is entitled "Variation under domestication" and deals with the breeding of pigeons (which Darwin himself enjoyed) and other animals.

Artificial selection and natural selection are the same in that, through both processes, only some members of a population survive to reproduce. Those individuals that reproduce are more likely to pass on the genes that allowed them to survive and reproduce, and subsequent generations will therefore be better adapted for survival and reproduction.

The major difference is that with natural selection, environmental conditions (weather, availability of food and mates, quality of parental care received, etc.) influence survival and reproduction. In artificial selection, human needs or whims are the most salient environmental conditions, and we determine which pup or colt or chick survives to reproduce based on a variety of aesthetic and practical considerations (is its coat too short or wiry? is it a good racer? does it lay an egg every day?). Because humans are in more or less complete control, artificial selection often takes a shorter time than natural selection.