Reports of the National Center for Science Education
Volume
17
No.
5
September-October
1997
Why Teach Evolution?
At first. the student asked if an "alternative assignment" could be arranged for her because of her feelings about evolution. Bruce considered having her withdraw from his biology class and take a physical science course instead. However, she insisted on the alternative assignment. Bruce discussed the issue with the girl's parents, and with his principal and counselors. Ultimately, the girl decided to stay in class. She agreed that it is better to learn about an issue before taking a stand against it — a very mature decision!
With his permission, we have reprinted Bruce's response to the videotape and the student's request.]
I am writing this letter in response to your recent request that I show the videotape of the Hoftmantown Baptist Church presentation on the creationism/evolution topic to my Biology I classes. I wanted to try to explain to you as clearly and as completely as possible why I have decided not to show this tape. As you may appreciate, for many people this is a tremendously emotional issue, when in fact, it should not be at all. In light of this emotional atmosphere, I hope to make you aware of the fact that my objections to showing the tape are based on rational thought and the desire to promote science.
My first, and perhaps greatest, area of concern is how the gentleman making the presentation gave his listeners a very grim set of consequences arising from making a choice between the two sets of ideas. I very strongly disagree with him that if one finds the ideas of evolution and natural selection acceptable, then it must follow that there is no God, no Heaven and no Hell. According to the speaker, acceptance of the ideas of biological evolution must ultimately lead one to conclude that life itself has no purpose! I find this effort to arouse fear in others completely unreasonable and even patently unfair. To start a presentation that purports to be objective with such an emotional outburst plays on the fears of people in an unacceptable and even cruel manner.
I have been teaching the basic tenets of evolutionary thought for twenty two years now, and I would never consider starting this unit with a statement demanding a choice be made between the two points of view on the basis of unreasonable fear! Demanding such a choice is diametrically opposed to the basic nature of science, which implores us to continually seek out evidence related to natural phenomena as a means of being able to explain these phenomena rationally.
My second area of deep concern regarding this presentation is that, along with presenting a fearful and agonizing choice to his audience, the speaker also dispenses gross misinformation. I will give the speaker the benefit of the doubt that these mistakes came from simple errors as he conducted his "research" on evolution in preparation for this presentation. I also believe that if he had a more thorough foundation in the biological sciences, these errors would likely not have been made at all.
One of the first errors is found in the speaker's account of the big bang theory. He mentions that a large quantity of dust and chemicals came together and formed a big bang. In fact, the events of the big bang actually formed the matter after the initial explosion. The speaker has mis-takenly reversed the sequence of the events. Curtis and Barnes, in the fifth edition of An Introduction to Biology, write on page 19 "Our universe began, according to current theory, with the 'big bang', a tremendous explosion that filled all space. Prior to this, all of the energy and matter of the present universe is thought to have existed in the form of pure energy, compressed into an infinitesimally small point. This energy was released by the 'big bang' and every particle of matter formed from the energy was hurled away from every other particle." The text goes on to explain how protons and neutrons were then formed as the temperatures cooled.
The speaker next talks about how the accretion of this matter into gas clouds which formed galaxies, planets and solar systems was all due to random chance. In fact, the laws of physics predict such an accumulation of matter, even accounting for the complex orbital and celestial mechanics of these systems!
The speaker then goes on to discuss how he has no problems with the evolutionary tenet of microevolution, which he presents as the biological mechanisms that enable a single animal or plant to change or adapt. Again, he is wrong. In their textbook, Biology, The Science of Life, Wallace, Sanders and Ferl state that microevolution, "is evolutionary change below the species level, including changes in gene frequencies, brought about by natural selection and random drift". The speaker also is in error when he states that a single organism is able to adapt. In fact, adaptation occurs at the level of the population and usually requires a great deal of time in which to occur.
The speaker also presents an interesting system to explain why mules are sterile. He states that God, in an effort to insure that organisms only breed within their "kind", has made the mule, the progeny of a horse and donkey mating, sterile. This idea simply has no basis in biological fact. In fact, Wallace, Sanders and Feri state that a mule, "is unable to reproduce successfully because abnormal meiosis in the hybrid produces abnormal gametes."
There are many more inaccuracies and inconsistencies in the presentation, such as the speaker's assertion that every major form of animal, such as elephants, has appeared in the fossil record quite suddenly. This is simply not based on any real evidence. In fact, there is a great deal of hard fossil evidence to the contrary.
Finally, when the speaker begins to cite the Second Law of Thermodynamics to refute the theory of evolution, I began to realize his "research" likely included only literature supplied to him by various creationist groups. I have long heard the arguments from creationists stating that all of the universe is running down, which of course, is quite true. The universe, ever since the "big bang", has been growing more and more random, or increasing in entropy. However, the laws of thermodynamics describe the behavior of matter and energy in what are referred to as "isolated systems", which are theoretical constructs developed by physicists. Isolated systems — those in which matter or energy cannot enter or leave — do not really exist, but are contrived as models by scientists who wish to test their ideas under hypothetical conditions that can be limited and controlled. In other words, isolated systems are closed systems, where there is no input or output of energy or matter. The living world, in contrast, exists in an open system, where there is a constant input of energy, ultimately from the sun. The result is that life is able to use vast quantities of energy through such mechanisms as photosynthesis to slow entropy, while your house, unless it is radically different in composition from mine, is not able to trap energy for its routine maintenance and upkeep!
The introduction of the Laws of Thermodynamics into the presentation of course led to the very dramatic and yet somehow sad demonstration where the speaker smashed an alarm clock to pieces and then facetiously waited for it to reassemble itseif. Of course, without the ability to capture energy from the environment, the result was a permanently compartmentalized alarm clock! I wish the speaker could have seen a similar demonstration I saw in my Invertebrate Zoology class at the University of New Mexico! Here, the professor took a small section of a live sponge and put it into a blender. He then pressed the button for a few seconds so that the sponge was reduced to a "puree" . He then set the mixture aside until the next class meeting a few days later. When we came in, the sponge had reassembled itself! The difference, of course, is that the living sponge is able to take in energy to power this re-assembly.
There is a great deal of highiy emotional dialog currently going on about teaching what are referred to as "alternative theories of evolution or creation" in science classes. I think that at some point teachers should be given credit for having some intelligence and sensitivity in this matter. They should be given credit for having enough intelligence and knowledge of subject matter in their teaching fields to be able to teach mainstream ideas in the limited time at their disposal. With the call from some quarters that alternative ideas about the origin of life be taught in high school biology classrooms, I am waiting for demands from these same individuals or others that geography teachers also teach the old flat earth theory. I am also expecting that chemistry teachers will soon be required to teach the outdated phlogiston theory to their students. Will physics teachers next be required to present alternatives to the laws of gravity?
At some point in this conflict, I believe biology teachers must state clearly and calmly that what they are teaching are ideas that have been carefully developed and expanded over many years of rigorous scientific endeavor. We are not attempting to warp young minds. What we are attempting to do is simply present an elegant construct of how life began on this planet and how it has come to be present in such bewildering and majestic abundance and diversity. I always make it a point to tell my students that the theory of evolution is a theory. To those ungrounded in the vocabulary of science, the term "theory" implies a largely untested set of ideas. In fact, Curtis and Barnes describe a theory as "a generalization based on many observations and experiments; a verified hypothesis". The mechanisms of evolution, such as natural selection, are regarded as scientific law. As we discuss the status of the theory of evolution, my students always want to know how I feel about the matter. At this point, I tell them that I personally and professionally regard the tenets of evolution as fact. However, I make it very clear that this is my own opimon and that they should listen to the ideas presented in class before they reach their own conclusions.
In conclusion, I do not plan to show this video tape to my Biology I students because it only offers emotional, irrational and erroneous attacks on an elegant and vibrant explanation for the marvelous complexity and diversity of life on this planet. People who insist on attacking evolutionary thought in this manner do so with an insulting air of ridicule and derision, with no hard evidence or facts of their own to offer. Our students deserve much better.
This version might differ slightly from the print publication.