One of the hardest concepts to get across to students is that living things don't evolve "because they need to in order to survive". If need was all that was required, over 99% of all the organisms that have ever lived wouldn't be extinct. The assumption is a reversion to the "magical thinking" that is so prevalent in our society and so inappropriate to science.
Science takes the approach that all natural processes, including
evolution, work solely through the workings of natural law. The fact that science has
proven again and again to be more useful in understanding the natural universe than any
other method of investigation shows conclusively that it's on the right track. Thus
evolution results in change, in survival or extinction, strictly according to
unfeeling, unchanging laws. The nonrandom processes of natural selection may lead to
survival—but may equally well lead to adaptations useful now but disastrous in the
long run. Needs and wants no more affect the course of evolution than the needs and
wants of several million players affect the outcome of the lottery.
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.