Science Tests Truth, Falsity of Evolution Theories
by Carl Bajema
Guest Commentary by Dr. Carl Bajema, Professor of Biology,
Grand Valley State University
Grand Rapids Press, 25 January 2001, p. A13
The January 1 guest column by Jerry Popiel on the subject “Theory of Evolution Disproven Regularly” is riddled with erroneous statements and requires a response. I will address four of the numerous blatantly erroneous statements that Jerry Popiel made in his guest editorial column.
(1)Mr. Popeil makes the erroneous statement that evolution can only occur by chance. He contends that evolutionary scientists teach students “to believe they have descended by pure chance from pond scum.”
Evolution (genetic change in a population) is scientifically understood as a two-step process that is repeated every generation. Evolution involves the generation of new genetic variation which is due in large part to chance processes such as mutation and sampling error (genetic drift). Natural selection operates on genetic variation each generation. Darwinian selection is the anti-chance ecological process that produces adaptive evolution rather than just random genetic change.
Selection operating in nature does far more than just subtract harmful genes and accumulate those mutant genes that are beneficial. Selection is a powerful process that produces exponential genetic change by (1) multiplying genes and by (2) selective recombination, that is, by selective mating which produces new individual organisms having new coalitions of adaptive genes by combining the adaptive successes from many ancestors.
This “speedy strongman” version of Darwinian selection theory stands in stark contrast to the “weak strawman” version which only allows selection to merely perform the negative task of weeding out harmful mutations.
(2) Mr. Popeil makes the erroneous statement that all of the evolution going on now (evolution of antibiotic resistance, etc.) involves the net loss of genetic information and therefore mutations are always the exact opposite of what is needed for evolution to take place. Scientists have identified a number of processes whereby genetic information can increase. Mr. Popeil has presented the Press readers with a very inadequate understanding of mutations which fits his religious beliefs but which misrepresents what goes on in living organisms.
Scientists have identified a number of natural processes that add DNA which results in a net increase in genetic information. Duplicated genes can be produced in at least two ways: Unequal crossing over between DNA on adjacent chromosomes; and the natural processes that produce polyploidy. These duplicated genes which can undergo further mutations provide the net increase in raw genetic information material for selection to operate on.
(3) Mr. Popeil makes the erroneous statement that scientists have never found a fossil of a transitional form. Paleontologists have found numerous hominid fossils that have transitional characteristics with respect to the size of the cranium (brain), size and shape of the face, teeth, etc. Numerous transitional fossils have also been found with respect to reptiles and mammals.
(4) Mr. Popeil contends that secularists are afraid of the truth. Science is our secular way for attempting to ascertain the truth or falsity of a statement. Scientists continue to construct and test theories concerning both past evolution and ongoing evolution. The discovery of Mendelian genetic inheritance patterns, the molecular structure of genes, and the existence as well as movement of continental plates have provided major scientific tests of Charles Darwin’s “descent with modification” by selection theory in the last century. We scientists are not afraid of the truth as Mr. Popeil contends. The scientific strategy for testing claims about what has happened or or what is happening in nature is a powerful strategy for learning about the accuracy of claims made about living organisms.
We human beings are more than just a very interesting end product of evolutionary processes that operated in the past. Evolution by selection operates on mutations within each one of us keeping us alive (the adaptive evolution of antibody producing cells) and frequently killing us (cancer).
Darwinian selection operating on heritable variations is the scientific theory that unifies biology. Students and other citizens need a better scientific understanding of the natural processes involved in producing ongoing as well as past evolution.
Dr. Carl Bajema is Professor of Biology at Grand Valley State University where he has been a member of the faculty since 1964. Professor Bajema is the author of the model Michigan Science Education Guideline for the teaching of evolution which was adopted unanimously by the State Board of Education in August, 1995.
