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Desert Diary


Some people have the impression that Mother Nature follows the rule of "waste not, want not". Unfortunately, that's not the case and one of the better reasons to believe that life blindly follows natural law. A good example is natural selection. This evolutionary force for adaptation works because only a portion of potential offspring manage to survive to reproduce. On average, those survive because they are better fit for their environment than are those who don't make it.

All successful organisms produce far more potential offspring over time than can possibly survive. Darwin knew this, and even calculated that one of the slowest breeders, elephants, would end up with nearly 19 million descendants from a single pair after only some 750 years were all to live out their potential life span. Nineteen million elephants isn't enough? Run it through another 750 years starting with those 19 million, and the resulting 180,500,000 elephants should be sufficient for anyone. The point is, that in the long run, only a few of the potential survive--waste on a massive scale!
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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.

African Elephant

African Elephant with young, photograph by Gary M. Stolz, courtesy of the U.S. Fish and Wildlife Service. rule


Ridley, M. 1993. Evolution. Blackwell Scientific Publications, Boston.

Web Resources

Elephant Calculator. Corrects Darwin's poor math and has a calculator that allows one to automatically calculate the number of elephants after any period of time. rule