Darwin proposed the theory of natural selection to explain evolution. Natural selection is the process by which organisms better adapted to their environment are more likely to survive and reproduce, passing on favorable traits. Darwin identified key components of natural selection: overproduction of offspring, variation among individuals, and competition for limited resources. Those individuals possessing variations that increase chances of survival will be selected through surviving and reproducing, passing on their beneficial traits. Over many generations, this process can lead to changes in a species.