Character displacement

Character displacement is the evolutionary pattern in which similar species living in the same region become more different from each other where their ranges overlap, but more similar where they do not, driven by competition between them. The underlying logic is the competitive exclusion principle: two species competing for the same resources can coexist stably only if they come to occupy distinct ecological niches, since otherwise one species eventually eliminates the other. William L. Brown Jr. and E. O. Wilson formally described the phenomenon in 1956, distinguishing reproductive character displacement, which reinforces barriers to interbreeding, from ecological character displacement, which is driven by competition for resources. The clearest illustration comes from the Galapagos finches: where two finch species occur together, their beak sizes and depths diverge sharply so each can exploit a different range of seeds, while on islands where only one of the two species is present, its beak size settles at an intermediate value closer to that of the other species. Character displacement has since been documented across many different groups of organisms and is considered an important force in both speciation and the structuring of ecological communities. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/