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Desert Diary


Sometimes biologists talk about an animal being preadapted for this, that, or the other thing. By this, they mean that, by happenstance, something turns out to be fit for circumstances it didn't evolve for. Such as wolves having evolved a social system that happened to fit in nicely with human systems, giving us, in time, the domestic dog. Or, less seriously, ears and noses, preadapted to holding eyeglasses in place.

Social systems and body form aren't the only kinds of preadaptation. The only wild animal that many city dwellers recognize is the familiar pigeon, technically known by ornithologists as Rock Doves. This bird was beautifully preadapted ecologically for city life. A native of the Old World, it nested in nooks and crannies of cliffs, safe from most terrestrial predators. Look around any of today's cities, and what are the tall buildings? Cliffs, that's what they are! Moreover, cliffs supplied with ledges that provide the perfect nesting places. Most city people consider them as pests, but perhaps they really should be thought of as exemplars of preadaptation.
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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.

Rock Dove

Rock Dove (Columba livia). Photograph by Dr. Lloyd Glenn Ingles, © California Academy of Sciences.



Strickberger, M. W. 2000. Evolution. Third edition, Jones and Bartlett Publishers, Sudbury, MA.