Evolution is a process, but this process relies on mechanisms to make it work. Some of the mechanisms which are claimed to make evolution “go” are natural selection, mutations, and a few others. These will be the topic of this discussion, “Are the mechanisms of evolution good enough to make evolution work?” Anticipating the argument that maybe we don’t know yet what the mechanisms were which brought about evolution, we must remember that if these mechanisms operated in the past and no longer operate today, there is no way of examining their usefulness for evolution, so they are outside the realm of scientific study. But many evolutionists will say that the following mechanisms are good enough for evolution, so we will examine them.
Natural selection
The importance of natural selection for evolution can be seen in the following quote, “The evolutionary drive towards complexity comes, in those lineages where it comes at all, not from any inherent propensity for increased complexity, and not from biased mutation. It comes from natural selection: the process which, as far as we know, is the only process ultimately capable of generating complexity out of simplicity” (Dawkins, 2006:150-151). Of course, there are other evolutionists who would put emphasis on mutations, but mutations will be examined a little lower.
Let us begin with a textbook definition for natural selection, “Here is a short definition: Natural selection is a process in which the differential adaptation of organisms to their environment selects those traits that will be passed on with greater frequency from one generation to the next” [emphasis in original] (Krogh, 2007:279). To restate, natural selection selects organisms that are better adapted to their environment so their genes get passed on, while poorly adapted organisms are eliminated along with their genes.
Natural selection is a simple principle, and quite observable in nature. Animals that cannot run as fast end up as lunch for their predators, so if they could not grow offspring before their death, their genes are eliminated from the gene pool. But here’s the crucial point, natural selection has nothing to select from to increase complexity and further evolution. Natural selection would be a fine mechanism working for evolution if there were another mechanism to produce the genetic changes necessary to make an organism better adapted for its environment. Then all natural selection would do is select these organisms. However, no such mechanism exists. Mutations might be credited with doing the job, but their credentials will be examined in the next section.
Another problem with natural selection is that it would actually work against evolution during the intermediate stages of an evolving organism. Søren Løvtrup explains, “And the reasons for rejecting Darwin’s proposal were many, but first of all that many innovations cannot possibly come into existence through accumulation of many small steps, and even if they can, natural selection cannot accomplish it, because incipient and intermediate stages are not advantageous” (Løvtrup, 1987:274-275). Now Løvtrup believes in evolution, but with macromutations, which is even more implausible and yet to be observed. But he made an excellent point, “incipient and intermediate stages are not advantageous.” For natural selection to select an organism, that organism would have to be well-adapted to its environment. Let us imagine this picture, an early reptile with fully functioning forelimbs begins to slowly evolve to having wings. The arms or legs, which were good at grasping or locomotion, are now changing into wings. Give it as many hundreds, thousands, or millions of years as you want, but there comes a point in time when these forelimbs would be useless for both their old function (grasping or locomotion) and their new function (flight). These forelimbs would not be as useful at grasping or locomotion when they begin to take the shape of a wing, and yet they wouldn’t be good enough for flight if they were still developing. So what does natural selection do? Natural selection eliminates this weird creature, because it is not well-adapted to its environment! Natural selection would actually prevent evolution on many occasions, not help it.
Mutations
We have seen that natural selection has nothing to select from, but evolutionists may object and say that mutations bring about the changes which natural selection selects. Mutations are said to be important for evolution, “The process of mutation is the only known source of the raw materials of genetic variability, and hence of evolution” (Dobzhansky, 1957:385). Now we will examine whether mutations have the necessary credentials to help evolution.
What are mutations? A biology textbook describes mutations as “accidental reorderings of DNA sequences” and “mistakes” (Krogh, 2007:211). Basically, mutations occur when some DNA code is reordered, deleted, or altered in some other way. Mutations can happen when code is improperly copied, or when chemicals or radiation alter the code, etc. So if mutations are mistakes which happen in DNA, how can they be useful for evolution? That is a good question! Evolutionists claim that sometimes these mistakes can actually help organisms adapt to their environment better, and these are the organisms that get selected by natural selection, and then the process repeats.
There are many problems with mutations not being good enough for evolution. To get down to the gist of the bigger argument, mutations are alterations to pre-existing genetic code. Mutations do not provide new genetic information, i.e., useful and functional code. Mistakes do not produce new functional code for new structures that would increase adaptability. So mutations are of no use to increase genetic information, and natural selection is still waiting for something to select.
An additional problem is that few mutations are of the right type for evolution. There are 3 types of mutations: beneficial, neutral, and harmful. Most mutations are of the neutral and harmful categories. John Sanford says, “I have seen estimates of the ratio of deleterious-to-beneficial mutations which range from one thousand to one, up to one million to one” (Sanford, 2005:24). Evolution would only benefit from beneficial mutations, but these are very rare. Here is one interesting explanation for the rarity of beneficial mutations, “In nature, new favourable mutations must be rare. This is because existing species are the result of past selection, which will have brought them close to the best obtainable adaptation to their surroundings, so that most mutations (changes) will decrease that adaptation” (Patterson, 1978:70-71). What Colin Patterson basically said is, “Everything has evolved just about as good as it gets, so today’s mutations have a hard time making things better.” Maybe Patterson is missing the alternative, perhaps everything was designed just about as good as it gets, so mutations (mistakes) are having a hard time making things better. And the whole argument shifts if we look not at the result of a mutation, but what the mutation itself does. Sure, it may benefit beetles on a windy island if they lose their wings so they can’t fly and be blown into the ocean, but the mutation itself was harmful. The beetles lost the code to make their wings function or grow! Mutations are mistakes, they alter previously functioning code, which makes their essence harmful. You won’t find mutations that help wingless beetles slowly develop wings to better adapt to other environments, and yet this is exactly what evolution needs.
A further problem with mutations is that only mutations in reproductive cells and organs get passed on to offspring (Patterson, 1978:57). Even if the arms of a reptile were mutated into wings and made that creature fly their whole life, that creature’s babies would not be born with wings! This would render the whole mutation mechanism useless for the evolution of that species. Only mutations in the sperm, egg, or related reproductive organs can influence what the offspring will be like. So not only are beneficial mutations rare, but they have to happen in the right place to make a positive difference for evolution.
Another difficulty for mutations is making any “selectable” difference. Most mutations only make small changes, but these changes cannot be selected or deleted by natural selection unless they clearly influence an organism’s adaptability to the environment. So most mutations, because they are harmful, will continue to collect up in an organism until they do make a difference, a difference for the worse (Baumgardner, 2008:5). This is the real price evolution would have to pay for using the “help” of mutations. Another way to see this problem is by comparison with photocopies, “When the mutation rate is very high, no living system can avoid the path to autodestruction. Each cycle increases the “noise” and erases crucial information, like a series of increasingly poor photocopies; ultimately, the text becomes illegible” (Denton, 1996:267).
No, mutations do not have what it takes to help evolution. In fact, they would most certainly hinder or stop evolution sooner than they would help it. Thus natural selection is still left hungry for some beneficial adaptations to select. So much for the main mechanisms of evolution!
Other mechanisms
Natural selection and mutations are the main mechanisms of evolution, but a few others will be examined for a more complete picture. Some of the other mechanisms for evolution are gene flow (movement of genes by migration) (Krogh, 2007:276), genetic drift (chance changes of the number of alleles) (Krogh, 2007:277), sexual selection (selection of mates influencing transfer of genes) (Krogh, 2007:279), and isolation (Krogh, 2007:294-295). But the problem with these mechanisms is that gene flow and genetic drift can hurt just as much as they can help evolution (Krogh, 2007:280), and sexual selection and isolation explain how genes get transferred or isolated but not how organisms adapt to their environment. The above mechanisms might be used in conjunction with natural selection and mutations to explain certain phenomena, but without natural selection and mutations these mechanisms are of no use to evolution. So the answer to the big question, “Are the mechanisms of evolution good enough to make evolution work?” is a clear “No.”
Works Cited
Baumgardner, John. “Exploring the Limitations of the Scientific Method.” Acts & Facts 37:3 (2008).
Dawkins, Richard. The God Delusion. Boston: Houghton Mifflin Company, 2006.
Denton, Michael. Evolution: A Theory in Crisis. (Paperback edition) Bethesda, MD: Adler & Adler Publishers Inc., 1996.
Dobzhansky, Theodosius. “On Methods of Evolutionary Biology and Anthropology.” American Scientist 45 (December 1957).
Krogh, David. Brief Guide to Biology with Physiology. Upper Saddle River, NJ: Pearson Prentice Hall, 2007.
Løvtrup, Søren. Darwinism: The Refutation of a Myth. London, New York, Sydney: Croom Helm, 1987.
Patterson, Colin. Evolution. Ithaca, NY: Cornell University Press, 1978.
Sanford, John C. Genetic Entropy & The Mystery of the Genome. Lima, New York: Ivan Press, 2005.