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Desert Diary


There are lots of terms to describe the interrelationships between different species of organisms. Everyone knows competition, where two different species vie for the same, limited resource. It might be noted, though, that the praising of competition by our capitalist system may mask the fact that it's harmful to the competitors no matter how good for the consumer—neither gets everything it wants.

Most people also recognize mutualism, though possibly not under that name. This is where two species interact in such a way that both benefit. Bats of the Chihuahuan Desert that feed on nectar and pollen while at the same time transferring pollen from plant to plant is a good example.

In some ways perhaps, the saddest interaction is amensalism. This is the case where the individuals of one species are harmed while those of the other species are neither harmed nor benefited. Streamside vegetation, for example, frequently is trampled by animals coming to drink. Those animals gain nothing from the trampling, but pity the poor plant under the hoof of an 800-pound cow!
pen and ink


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.