Re: Darwinian and non-Darwinian (was Re: RFEP & ID)

Date: Fri Sep 26 2003 - 13:06:34 EDT

  • Next message: Steve Petermann: "Re: Darwinian and non-Darwinian (was Re: RFEP & ID)"

    This distinction Jim makes is more or less correct, but ambiguity in use of
    the term "Darwinian" can lead to some false characterization of
    evolutionary theory.

    I don't think there is an evolutionary biologist alive who doesn't believe
    that natural selection is a significant (even the main) mechanism effecting
    evolution. Nearly every morphological, physiological, and behavioral
    feature that affects how an organism interacts with its environment owes
    its properties to the operation of selection. (I say "how the organims
    interacts with its environment" because I suppose one could name a number
    of features such as silent nucleotide substitutions that don't change the
    protein sequence coded as examples where selection is irrelevant to their
    fixation or loss in a population). Where people differ is whether and when
    other factors are significant alongside selection. For example drift is
    very significant in determining the likelihood that a variant will exist
    long enough in a population to be able to be selected, but no one really
    contends that natural selection is not important.

    I think to claim that there is such a wide distinction is a poor
    representation of the true consensus of evolutionary biologists.
    "Darwinian evolution" is a bad label because it has been used in both
    general and specific senses (General=evolution involving natural selection
    as a main mechanism. Specific =strong gradualism). This ambiguity of usage
    has its origin in evolutionary biology itself; however, the meanings are
    distinguished by context within the evolutionary biology discussions. In
    wider layperson discussion, the ambiguity adds to confusion, leading people
    to think that there isn't much of a consensus in evolutionary biology.


                        Schneider" To: <>, <>
                        <rjschn39@bellso cc:
              > Subject: Darwinian and non-Darwinian (was Re: RFEP & ID)
                        Sent by:
                        09/26/03 10:54

    Jim writes:

    > Generally, when we describe someone as a "Darwinian," we are saying that
    > they believe that gradualism and selection are the important features in
    > evolutionary process. It seems that ecologists tend to be hard-core
    > Darwinian.
    > Non-Darwinian biologists view drift, founder effects, macromutations
    > with multiple effects) and similar processes as the important mechanisms
    > an evolutionary pathway. S.J. Gould popularized this in the punctuated
    > equilibrium model.
    > Jim Behnke
    > Asbury College
    > Wilmore, KY 40390 859-858-3511 x 2232

    Thanks, Jim. I'm grateful for this statement. But a query. Do not such
    phenomena as gene flow, genetic drift, founder effect, etc., still depend
    some way on selection, as in the establishment of a new population in a new
    environment (e.g., migration to an island), even though the rate of
    evolutionary change may be much more than gradual? Help me out in
    understanding and clarifying this point.

    Bob Schneider
    (Berea College ex-patriate now in Boone, NC)

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