Essay on Evolution There are many mechanisms that lead to evolutionary change. One of the most important mechanism in evolution is natural selection which is the differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Natural selection occurs when a environment makes a individual adapt to that certain environment by variations that arise by mutation and genetic recombination. Also it favors certain traits in a individual than other traits so that these favored traits will be presented in the next generation. Another mechanism of evolution is genetic drift. Genetic drift is a random change in a small gene pool