Re: Peppered Moths - in black and white (part 2 of 2)

Kevin O'Brien (
Wed, 31 Mar 1999 18:11:56 -0700

>How can variation be evolution? Variation is just bouncing around within
>determined limits.

No, it's not. Variation is not a verb, it's a noun; it specifies the
totallity of traits within a population, not the change in those traits.
Creationists have co-opted variation and turned it into a verb in an attempt
to invalidate so-called "microevolution" as proof of the validity of
evolution as a whole, but what they refer to as "variation" -- the change in
frequency of one or more traits within a population -- is by definition

>Evolution is something beyond this. Evolution is
>irreversible; the moth phenomenon is reversible; therefore, the
>phenomenon is not an instance of evolution. I don't think I'm making
>idiosyncratic definitions here.

As a matter of fact you are, but it is understandable. You have accepted as
true the creationist claim that "macroevolution" is the only true form of
evolution. Since "macroevolution" does involve more or less irreversible
change, it is natural for you to assume that evolution as a whole requires
irreversible change. However, "microevolution" is also evolution, even
though changes here are not always irreversible. What is important is that
evolution is a change in variation; it doesn't matter whether that change is
reversible or not.

Kevin L. O'Brien