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Evolution: just a change in allele frequencies?

Published: 27 June 2015 (GMT+10)
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Creationists should learn to spot the fallacy of equivocation—where someone illegitimately switches the definition of a word in the middle an argument—because evolutionists often trade on this error. S.U. from the U.S. needed assistance answering one such evolutionist.

He first quotes the critic (in brown) and then follows with his request for help (in green):

Of course humans are still humans. By humans, I’m assuming you mean the Homo genus. You said 500 years, and we’re macroorganisms.

"No biological evolution"

As I’ve said before, evolution is a continuous process. Our subspecies has evolved since 500 years ago. As one example, take the changed prevalence of genetic diseases. As these are caused by alleles (and therefore the frequency of the relevant alleles has changed), and evolution is the change in allele frequencies in gene pools over generations, this is biological evolution.

Humans are apes. The tips of our phylogenetic tree are really not that hard to understand.

This is a response I got from a person that I’m talking with and I’m not sure how to respond to this. Allele frequencies aren’t something that I’ve been taught and so I’m not sure what to do. Can you help me respond to this?

CMI’s  replies:

Hi S.U.,

We’re glad to help.

Your critic really hasn’t provided any substantive evidence for microbes-to-man evolution. All he’s done is point to biological variations that creationists acknowledge (indeed, we expect those variations and more), and he’s failed to give examples of the more significant types of changes that Darwinian evolution requires—like the production of novel structures that are highly complex but specified.

This is a common evolutionary tactic, to point to examples of variation within one kind of organism (humans, in this case), and then to claim that this proves all living things must have arisen from a common ancestor (so humans are related to pumpkins and porcupines). But this is a textbook example of the logical fallacy called equivocation. See Don’t fall for the bait and switch and The evolution train’s a-comin’ (Sorry, a-goin’ in the wrong direction).

To help you understand what the critic is saying, let me explain his terminology. An allele is just a variant, or alternate form, of a particular gene. For example, a gene for eye color may come in different forms, or alleles—some people have the allele for blue eyes, and some have the allele for brown eyes. Frequency refers to how many people in the population have those alleles. So a population might have 30% brown-eyed people and 70% blue-eyed people. A change in frequencies would happen if, several generations later, the population was now 15% brown eyes and 85% blue eyes. This could easily happen if the blue-eyed people tended to marry each other and have more babies on average than the brown-eyed people.

Now, the critic has defined biological evolution as this type of change—"the change in allele frequencies". But this is only ‘evolution’ in the most trivial sense. Notice, in the example above, we started with blue and brown eyes, and ended with blue and brown eyes. The only thing that changed was the relative percentages of those alleles in the population. But you’ll never turn a fish into a philosopher by that process! The kind of evolution we deny—universal common ancestry—requires a mechanism that can do more than just shuffle alleles around within the group, or even introduce new alleles by breaking and damaging existing ones (see The Three Rs of Evolution and Can mutations create new information?). It requires a mechanism that can generate reams of new genetic information that is characterized by a high degree of specified complexity.

So don’t be intimidated by the big words. This critic’s alleged proof for evolution is hopelessly inadequate. If you familiarize yourself with the articles linked above, you should not have any trouble giving an answer.

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