In practice, plant and animal breeders understood natural selection before Darwin did; they just didn’t know that they understood it. Farmers bred crops for maximum yield, and dog, horse, and pigeon fanciers selectively bred the animals with their favorite traits to produce more and more of the offspring with more and more exaggerated versions of those traits.
The process used by animal breeders and farmers is called artificial selection, but the underlying genetic process does not differ from natural selection, because the three conditions are satisfied. Artificial selection is considered a special case of natural selection, however, because the differential reproductive success is being determined by humans rather than by nature. Apple growers, for example, use artificial selection to produce the wide variety of apples now available. What is important is that it is still differential reproductive success, and the results are no different. It was a stroke of genius for Darwin to recognize that the same process farmers were using to develop new and better crop varieties is occurring naturally in every population on earth, and always has been.
Animal breeders and farmers are making use of natural selection when they modify their animals and crops through selective breeding, because the three conditions for natural selection are satisfied. Since the differential reproductive success is determined by humans rather than by nature, this type of natural selection is also called artificial selection.
Dog, horse, and pigeon breeds are produced through artificial selection. How many more examples can you think of?
342