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Desert Diary


In the interface between evolution and development, we're beginning to see that much of the difference between animals is, in a sense, similar to what we see going on in industry. Such products as automobiles are constructed out of modules—the motor module, the chassis module, the electrical module, and so on. In a new model year, some modules may be changed greatly while others remain unchanged. But even the most radically remodeled unit usually is based on earlier ones, consisting of the same components, but with the parts re-engineered.

Similarly, it appears that organisms are put together in genetic modules, the same components but drastically changed evolutionarily. The module guiding the development of the limb of a mammal, for example, is the same specifying that of a bird. It's just that the components of the module now do things slightly differently, the finger components in a bird reduced one way, those in a horse in another way. Just a switch-out of module components from the basic set of genes inherited from the common ancestor of birds and mammals.
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Listen to the Audio (mp3 format) as recorded by KTEP, National Public Radio for the Southwest.


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.