Competition—as well as cooperation—is a fact of life in nature as in human affairs. Unlike much of human competition, most organisms don't realize that they are competing, except possibly during the winning of mates.
Competition is most fierce within a species, for over the long term, only a relatively few of those conceived survive to produce the next generation. The next strongest competition tends to be between members of closely related species. Sharing a large part of their genetic makeup inherited from their common ancestor, they often require many of the same resources.
One result of competition between closely related species is the
dividing up of the landscape, the various species adapting to different ecological
aspects. For example, Deer Mice of the genus Peromyscus are common in the Chihuahuan
Desert. In the El Paso region, the Cactus Mouse chooses rocky slopes and sand dunes;
the Brush Mouse patches of oak and shrub; the Rock Mouse, mountain-top rocky slopes;
the White-footed Mouse, vegetation-choked arroyos; and the Deer Mouse whatever patch is
unoccupied by the other species.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.