From: onar@hsr.no (Onar Aam)
Subject: Re: Microevolution and Macroevolution
Organization: Rogaland University Centre
Date: Wed, 7 Oct 1992 09:46:56 GMT

>>"Microevolution" and "macroevolution" were meaningless expressions before
>>creationists put the spotlight on them. To an evolutionist micro- and
>>macroevolution virtually were the same thing because it was generally believed
>>that they were driven by the same causes. But creationists pointed out that you
>>could nuke fruitflies forever and get wird fruitflies, fruitflies with three
>>eyes, or legs instead of eyes etc., but they would still be within the
>>specie of fruitflies. And today we know why. It is because micro- and
>>macroevolution are independent drives. Thus, the two expressions HAS become
>>meaningfull in evolutionary terms. Ironically, perhaps, because of the
>>creationists.
>
>When I first ran across the terms "microevolution" and "macroevolution"
>in a creationist diatribe, I scuttled over to my nearest evolutionary
>reference (Invertebrate Paleontology and Evolution, 2ed, can't remember
>the author/editor) and found the following definitions (paraphrased):
>
>Microevolution:  evolution driven by forces of selection acting on
>	individuals of a species.
>Macroevolution:  evolution driven by forces of selection acting on
>	entire species or groups of species (sometimes referred to as
>	"species selection", if I remember correctly).
>
>The text suggested that microevolution was the primary cause ofspeciation and adaptive evolution, and that macroevolution had a much
>lesser effect on these phenomena.
>
>Armed with these definitions, I went back to my creationist literature
>to read numerous quotes from "eminent" biologists who claimed that
>while microevolution was undeniable, macroevolution was questionable
>as an explanation for the development of life.  Which turns out to be
>exactly right, except that the creationists had cleverly re-defined the
>terms to refer to the scope of the changes in a given species (resulting
>in a nearly opposite meaning) before supplying the quotations for my
>consideration.
>
>So what is the current state of affairs?  Are evolutionary scientists
>now using the creationist definition of the terms, or do the above
>definitions still hold sway?
>

There is a huge mixup here. It is due to the defenition of scale. When
creationists talk of micro- and macro- they mean the MAGNITUDE of change of a
specie. The above defenitions, which also are correct, imply the SCALE upon which
evolution occurs (i.e. antnests are due to macroevolution).

These are separate topics in evolution. Let me clear things up a bit.

In the meaning of magnitude:


microevolution is the change which occurs within a specie. In short, diversity.

macroevolution is the change which "transforms" a specie into another. In short,
INCREASE in complexity.

What creationists also has pointed out: Evolutionary change, more often than not,
 occurs suddenly and in steps. Which is absolutely true. 


On the other hand I agree that it is a filthy trick from creationists to mix
these terms in quotes. (Unless, of course, they don't understand the meaning of
the terms which, when I think about, actually makes more sence.) 




Onar.

 


 
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