Genetic Specialization Charles Darwin's discovery of the Law of Natural Selection was momentous. Actually, though, the law itself is quite simple. If there is a variation of expressed traits in an interbreeding population and if there is a survival advantage of some of the traits over the others, then those traits with the greater survival value will tend to spread throughout the population to the exclusion of the others. Thus, he did not understand how variation of traits was dependent upon and limited by the genetic options already available within a gene pool. The important thing is that Darwin understood at a superficial level the principles of selection but did not understand the actual mechanism taking place in the genes and chromosomes.
Natural selection is basically a specialization process.
It simply selects for those genes that are most efficient and effective within the options available from the gene pool. As it selects for the most effective options, the lesser options eventually disappear. Examples of controlled selection are with dog-breeders, where the goal is to get uniformity from generation to generation. When a new breed of dog is created, it does so at the cost of losing the genetic information contained in the undesired genes which are bred out. In nature it is generally desirable to have a fair amount of variation available so that as environmental conditions change, a species has the ability to respond to those changes using options that are already available from within its gene pool.