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Desert Diary


Just as all other things, organisms are controlled by the laws of physics. This is both a blessing and a curse. A blessing in that natural selection uses these laws for survival; a curse in that natural selection is strictly bound by them.

As we evolved an active life style in the hot, open plains of Africa, shedding body heat was a must. We've used the laws of physics to reduce our body heat by evaporation, conduction, and radiation. We have evolved to be perhaps the sweatiest animals on the face of the earth, using evaporative cooling efficiently. We've lost most of the fur ubiquitous among our relatives, allowing the air next to our skin that's been heated by conduction to carry away that heat on currents of air. Under heat stress, the blood vessels of our skin dilate, bringing near the surface hot blood that radiates out heat. On a hot summer day, we may complain bitterly about the stresses brought on by our desert heat. Quit your griping—just concentrate on being sweaty, conductive, and radiant!
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Listen to the Audio (mp3 format) as recorded by KTEP, 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.