Russ,
I hope has been clear to everybody from the start that I am not a proper biologist. My degree is in psychology and my postdoctoral year was as an ethologist. I will leave it to Eric to tell you the same thing about himself.
If you ask me on my best days, I will say that what evolves are taxa. Nothing individual can evolve. To me, evolution is just the flexing of taxa to match the circumstances of their time. It is this that natural selection explains..
Nick
Nicholas S. Thompson
Emeritus Professor of Psychology and Biology
Clark University
http://home.earthlink.net/~nickthompson/naturaldesigns/
From: Russ Abbott [mailto:[hidden email]]
Sent: Monday, May 09, 2011 4:25 PM
To: FRIAM
Cc: Thompson, Nick; Eric Charles
Subject: What evolves?
I'm hoping you will help me think through this apparently simple question.
When we use the term evolution, we have something in mind that we all seem to understand. But I'd like to ask this question: what is it that evolves?
We generally mean more by evolution than just that change occurs--although that is one of the looser meaning of the term. We normally think in terms of a thing, perhaps abstract, e.g,. a species, that evolves. Of course that's not quite right since evolution also involves the creation of new species. Besides, the very notion of species is controversial. (But that's a different discussion.)
Is it appropriate to say that there is generally a thing, an entity, that evolves? The question is not just limited to biological evolution. I'm willing to consider broader answers. But in any context, is it reasonable to expect that the sentence "X evolves" will generally have a reasonably clear referent for its subject?
An alternative is to say that what we mean by "X evolves" is really "evolution occurs." Does that help? It's not clear to me that it does since the question then becomes what do we means by "evolution occurs" other than that change happens. Evolution is (intuitively) a specific kind of change. But can we characterize it more clearly?
I'm copying Nick and Eric explicitly because I'm especially interested in what biologists have to say about this.
-- Russ
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