Disruptive selection is said to occur when these organisms survive and those that do not lie at the extremes are eliminated. Directional selection is said to occur when one of the extremes of a trait distribution is eliminated. In nature, evolution takes place through a process called selection. In a group of organisms of the same species, differences occur in how prominent particular traits are. The offspring of organisms with traits that facilitate survival in the environment they are in have a higher chance of surviving. This process of selection gradually increases the number of organisms with particular traits and the species evolves.