Re: RM&NS and the whale (was But is it science)

From: Stephen E. Jones (
Date: Thu Oct 19 2000 - 09:38:25 EDT

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    Subject: Re: RM&NS and the whale (was But is it science)

    On Fri, 13 Oct 2000 01:32:10 -0500, Chris Cogan wrote:

    >SJ>In the case of 1. if a "roach" survives after Susan sprayed it with
    >>insecticide, how does Susan "see" that it did not survive because she
    >>did not spray it properly? Also how does Susan "see" that the "roach"
    >>does not die later without offspring?

    >CC>You've inverted selection. Organisms are selected *out* of the population,
    >not *into* it.

    I have not "inverted" anything. Natural selection can be looked
    at both as: 1) selecting for a desired trait; or 2) selecting
    out undesired traits.

    Usually it is the selecting for meaning is what is meant. Even
    the selecting out is implicitly selecting for what is left.

    CC>If roaches are sprayed and some die, they are selected out.

    See above. Selecting out and selecting for are two sides of
    the same coin. But usually it is the *survivors* who are
    spoken of having been naturally selected.

    But not being selected is a form of selection.

    CC>It really doesn't matter if she sprayed "properly" or not.

    Of course it does. The cockroach might have survived because not enough
    pesticide contacted it, not because it had a favourable allele which
    conferred resistance.

    CC>We know that
    >many roaches *are* killed by the poisons, and that some are not.

    This is a fallacy. That "many roaches *are* killed by the poisons" shows
    they are not resistant to it. But that "some are not" is not necessarily that
    they are "resistant to it". It might simply be that not enough pesticide
    contacted them.

    One would need either a carefully controlled experiment to see if those
    roaches that are surviving are doing so because they have become resistant
    to any particular insecticide.

    CC>In nature,
    >selection is not determined on the basis of whether some poison is
    >"properly" applied.

    It is if Chris is claiming that roaches in "nature" are becoming
    resistant to insecticide due to alleles that confer resistance to it
    being naturally `selected'.


    "How do new species arise? Darwin's original idea, that new species arise
    gradually from the action of natural selection over time, is now seriously in
    doubt. In fact Darwin was disappointingly vague and inexplicit about the
    actual mechanics of speciation (despite the title of his magnum opus). The
    events which lead to the 'creation' of new species are still largely a puzzle.
    Is selection alone strong enough to bring about new, distinct sexually
    isolated species in the wild? Is this process necessarily a gradual one, or
    may new species arise quite abruptly? The results of thousands of
    experiments and observations from nature are ambiguous natural selection
    may be strong enough to create adaptations, but some recent experiments
    suggest that selection may actually be irrelevant in the origin of species.
    There is also a wrangle over the speed at which new species are formed-the
    latest results implying that this may be sudden rather than gradual." (Leith
    B., "The Descent of Darwin: A Handbook of Doubts about Darwinism,"
    Collins: London, 1982, pp.22-23)
    Stephen E. Jones | Ph. +61 8 9448 7439 |

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