Why Evolution is Wrong, post 2 of 10: An Example of Evolution.

     About half way through his book Why Evolution is True Jerry Coyne describes an instance of natural selection that is similar to the gypsy moth example that I gave in my last post.  He uses the example of coat color in wild mice to explain how natural selection dictates a different habitat for each variety of mouse.  Here is an excerpt of his description:

            Over time, due to the differential predation, lighter mice would have left more copies of their light genes     (they have a higher chance of surviving to reproduce) and as this process continued for generation after        generation, the population of beach mice would have evolved from black to light.

            Notice how he uses the world “evolve” to describe the change from dark colored mice to light colored mice.  I am sure that he did not do this by accident.  Word’s have meanings, and letters in a book are not usually the result of random, unintended keystrokes.  Coyne is implying that we see examples of modern day evolution occurring all around us every time we witness natural selection in action.  But as I implied in my last post, both evolutionists and young earth creationists believe in natural selection. The sticking point is where the genetic information displayed by the mice originally came from.  If he is correct that the genes in question originally evolved through a series of mutations that can be traced all the way back to the primordial soup, then yes, these are examples of evolution.  However, since Coyne does not attempt in this specific case to prove that these particular genes came about as the result of a mutation or series of mutation, his statement that this is evolution is an assumption, not a conclusion based on evidence.

            Evolution, however, doesn’t always need to be assumed.  Natural selection acting upon random mutations happens in real life, and we can prove it. The problem for evolutionists is that the kind of evolution that we witness today is completely incapable of explaining the origin of species.  Perhaps that is why evolutionists prefer to talk primarily about cases such as the one above where the mutation element is missing.

            One the best-known examples of evolution occurring in humans today is a disease called sickle cell anemia. It is a horrible condition caused by a simple point mutation*. As many of my readers already know, our DNA is actually a code that tells our bodies how to make proteins.  Proteins, the “building blocks” of our bodies, are long, stringy chemicals assembled by attaching amino acids together in a chain.  There are only a limited number of different kinds of amino acids our body uses, but these can be placed in many different arrangements to produce a great variety of proteins.  It’s kind of like building a sentence out of letters.  One kind of mutation (there are several kinds) is called a “point” mutation that happens when the DNA is copied wrong and ultimately produces one wrong “letter” in the protein “sentence.” This difference of one amino acid in the protein chain does not necessarily destroy the function of the polypeptide. It turns out that hemoglobin, the very complicated chemical that binds oxygen in blood, is one of these proteins which is manufactured from our DNA. A single point mutation at just the right location in our DNA produces a slightly different form of hemoglobin that is responsible for causing sickle cell anemia. This new version of hemoglobin is defective. It does not bind with oxygen as well as normal hemoglobin. People who have this condition are very unfortunate. If someone is born with a single set of sickle cell genes they will probably not experience the disease too badly, but if they are born with both sets of this gene, they will lead a painful life which may very well result in a premature death.

            At first this does not appear to be an example of evolution. Evolution, after all, is not the result of random mutations acting alone any more than it is the result of natural selection acting alone: the two parts must work together. An “evolutionary” gene, therefore, must be one that is naturally selected to survive. This is exactly what happens in sickle cell anemia.  The genetic change that produces sickle cell hemoglobin is actually a “good” mutation. Yes, it may cause premature death in some people, but in certain parts of the world it actually saves more lives than it destroys.  It turns out that the sickle-cell condition as a positive result: it makes the body immune to the effects of malaria. Therefore people who are born with one set of sickle cell genes and one set of unaltered genes can lead a relatively normal life unhindered by sickle cell anemia on the one hand, while at the same time possessing a valuable protection against malaria.  Since more people have one copy of the gene than two, natural selection “chooses” sickle-cell children to survive in many places where the threat of malaria is extremely high, such as in parts of Africa. Sickle cell anemia, therefore, is as much a result of natural selection as it is of mutation. If it wasn’t for its “positive” effects it probably wouldn’t have survived in humans.

            Tomorrow we will discuss the implications that this has for evolution.

*This example is found in Michael Behe’s book The Edge of Evolution.

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