What do selective breeding and natural selection have in common?
Both natural selection and selective breeding (sometimes called artificial selection) are forces that may influence the reproductive process. Natural selection is what occurs naturally (hence the name) to weed out less beneficial traits in a population and pass on those which are more beneficial to life in a particular environment. Artificial selection, on the other hand, involves human intervention to try and encourage a desired trait to be expressed more frequently in a population.
Let's consider two examples:
- Two bears mate in the wild. The parent bears both pass on half of their alleles to the cub.
- A dog breeder wants their white pet poodle to have white puppies. The breeder decides the dog should mate with another white poodle to increase the chances of having all-white puppies. The parent poodles mate and each passes on half their alleles to the puppies.
These two processes are essentially the same, but they differ in causation and desired end result. One might consider natural selection to be more "accidental" because the organisms mating do not have a desired outcome for their offspring. Many organisms, like plants, also mate quite accidentally — pollen is released and, if it sticks to another organism, lucky them! Artificial selection, on the other hand, is entirely influenced by the actions of a third-party to the reproductive process. It's very intentional.