Re: what comes next-the chicken or the fox?

From: David Campbell (bivalve@mailserv0.isis.unc.edu)
Date: Fri Jan 14 2000 - 12:35:41 EST

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    >Much knowledge that portents to have "scientific" basis has support from
    >rigorous laboratory testing. I like to call this "hard science" and
    >maybee there is a better term but I want to differentiate this from
    >"forensic science" is this is important. The differentiation is
    >significant because those who want science to be our beacon want
    >"forensic science" to have the same standing as "hard science."
    >
    >HS can be tested by an experiment. The experiment is quantitative and
    >can be repeated by many researchers over many generations. At some
    >point, it can be accepted as truth but the underlying issue is always
    >that the next generation should extend, test, and re-think.

    However, there is a forsenic component. I cannot experimentally determine
    whether you performed an experiment. Instead, I have to rely on the
    evidence that an experiment took place in the past. If a minor mutation in
    coelacanths produces toes like those of early amphibians, genetically
    related to the method of producing toes in modern tetrapods, it seems
    reasonable to suggest that was probably the mechanism by which they
    evolved, just as my replicating an experiment from your lab suggests that
    we did things the same way.

    >However(oops), the counter to this (and Carl Sagan tells of this in one
    >of his books) is the crazy little fruit fly. Dawg gone it. They have
    >raised millions and millions of these little bugs and put all kinds of
    >evolutionary stress on them and they just will not evolve( at least
    >according to Sagan).

    Given that geneticists do not want them to evolve into new kinds, this is
    not exactly surprising. Assuming there were some use to having antennae
    growing out of its head, eyes all over, or other bizzare mutations that
    have been produced in the lab, it seems likely that they would develop into
    very different kinds of organisms under natural conditions, and in fact the
    hundreds of kinds of fruit flies in Hawaii, the stalk-eyed flies of New
    Guinea, and the flightless bat commensals of New Zealand show that fruit
    flies can evolve into all sorts of things. However, geneticists want their
    flies to interbreed so they can study the genes. A new species goes into
    the trash, not into publication.

    Under particular selective regimes, the fruit flies have evolved. For
    example, when males were artificially bred so that female success did not
    affect them, they evolved ways of outcompeting other males that were also
    disadvantageous to the females.

    In other words, Sagan is not a biologist.

    David C.



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