If Ray means ‘undirected’ as in ‘undirected by an intelligent force,’ he is correct. But if he means it as in ‘random,’ he is incorrect. Although mutation is random, natural selection is the nonrandom change in allele frequencies in a population, with time, as per environmental pressures on genetic configurations that make the organisms in that population either more or less able to survive and to compete for resources.
Species do of course change over time by adaptation and natural selection, but some disagree that this indicates Darwinian evolution. For example, in looking at the variety available within dogs—from the tiny
It is always interesting to see the process of dog breeding used as part of an argument against the evolutionary model, given how well it actually supports it. Dog breeding is a form of artificial selection. Based on the desirability of given traits, a breeder decides the size and nature of the contribution given dogs make to his or her small, segregated population. By doing so, this acts as a drastic environmental change. The effect is a rapid change in phenotype, relative to the usual timescales of speciation in the evolutionary model. Over the past few centuries, more than 400 breeds of domestic dogs have been created—displaying a vast array of phenotypic variation (Young & Bannasch, n.d.). Since the timescale is so small, the selection is predominantly acting on preexisting genotypic variation, rather than on new variation introduced by mutation. This is confirmed by the large genetic variation observed in these dog breeds (Parker, Sutter, & Ostrander, n.d.), and by the extremely small genetic difference between them and the grey wolves from which they recently diverged (Savolainen, n.d.; Leonard,
There are tremendous variations among humans—from Asian to African to Aboriginal to Caucasian— but all are within the same species, Homo sapiens.
Bringing up human genetic variation is ironic, considering how it runs contrary to what Ray wrote in his section on DNA similarities about comparative genetic research between chimpanzees and humans. As I mentioned in my response to that section, regardless of how comparatively high or low human genetic variation is, it is observed to be significantly lower than that of chimpanzees (Stone et al., 2002; Fischer et al., 2004; Chimpanzee Sequencing and Analysis Consortium, 2005); as much as four time less (Kaessmann, 1999).That Ray mentioned such inter-species variability here, yet remained previously silent on it demonstrates his inconsistency and ignorance of the subject.
Admittedly, this puts a tremendous responsibility on mutations to accidentally create complex new body parts, and on natural selection to recognize the benefit these new parts will eventually convey and make sure the creatures with those new parts survive. As Stephen J. Gould explains:
The essence of Darwinism lies in a single phrase: natural selection is the creative force of evolutionary change. No one denies that selection will play a negative role in eliminating the unfit. Darwinian theories require that it create the fit as well.34
Firstly, Ray’s assertion that mutations somehow randomly happen to “create complex new body parts,” and that natural selection merely insures their persistence in the populations upon somehow “[recognizing their] benefit” is so outlandish a misrepresentation of the evolutionary model, that it is hard to believe he has any real understanding of the information pertinent to the model that he reports in this introduction. The following portions of my response to similar assertions Ray has made in his sections on vestiges and
Proteins do more than just catalyze reactions in an organism—they bind and interact with many other proteins and chemicals, as well as provide much of the organism’s structure. Mutations in genes that code for these proteins change the way the proteins interact, the way they arrange into structures, and the way they catalyze reactions. As in the example above, a mutation can change the efficiency of an enzyme in binding to its substrates and its rate of catalyzation; but it can also cause the enzyme to bind with additional substrates or to different ones all together. Regardless of a given protein’s roll in the organism, mutation can either change or replace the way it interacts, reacts, or arranges.
When the replaced function is necessary, and when there is only one copy of the gene that codes for the protein, mutations are often detrimental. But when the gene is a duplicate, resulting from a duplication of chromosomal
So how does natural selection achieve such a feat? Well, all living organisms reproduce. They also pass on a large amount of the information that makes their configuration what it is to their offspring. The third critical trait of living things is that there is a consistent increase in variability caused by mutation from each generation to the next. And finally, living organisms exist in populations for finite amounts of time, and must stave off their demise while competing for limited resources. All of these principles together have an interesting result. As new variation is introduced by mutation, modifications to proteins, such as the way the catalyze reactions and configure to form anatomical structures, that allow for more efficient performance of tasks in the organisms’ environment, the organisms become either more or less able to both survive and compete for resources (thrive) in their environment. The measure of this efficiency is called fitness. Configurations that increase fitness make the organism more able—and thus more likely—to make significant contributions to their populations’ gene pools. This increases the frequencies of the alleles with those configurations, with time. Likewise, the frequencies of alleles with configurations that decrease fitness decrease, with time. This process is called natural selection. Since the differences between species are observed to be structural and functional modifications that increase fitness in the organisms’ environments, this is powerful evidence that these differences were the result of decent with modification caused by mutation and natural selection.
Secondly, Ray also shows that he doesn’t even understand the quotes he cites on evolutionary theory. That quote by Gould affirms that in the evolutionary model, natural selection is the primary creator of structural and functional change. That directly contradicts Ray’s misinformed assertion in the preceding sentence that this roll is filled by mutation, and that natural selection merely acts on the organs created ex nihilo by mutation.
Scientific advances since
This is true. It is also true that, as has been repeatedly shown, those advances thoroughly confirm that the effect of natural selection on preexisting and new mutational genetic variation accounts for biological change over time and causes the proliferation of life.
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Fischer, A., V. Wiebe, S. Paabo, and M. Przeworski. "Evidence for a Complex Demographic History of Chimpanzees." Molecular Biology and Evolution 21.5 (2004): 799-808. <http://mbe.oxfordjournals.org/cgi/content/full/21/5/799>.
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