This is one of Stephen Jone's tagline quotations:
>--------------------------------------------------------------------------
>"The changes within a population have been termed microevolution, and
>they can indeed be accepted as a consequence of shifting gene frequencies.
>Changes above the species level-involving the origin of new species and the
>establishment of higher taxonomic patterns- are known as macroevolution.
>The central question of the Chicago conference was whether the
>mechanisms underlying microevolution can be extrapolated to explain the
>phenomena of macroevolution. At the risk of doing violence to the
>positions of some of the people at the meeting, the answer can be given as
>a clear, No." (Lewin R., "Evolutionary-Theory Under Fire: An historic
>conference in Chicago challenges the four-decade long dominance of the
>Modern Synthesis," Science, Vol. 210, pp.883-887, 21 November 1980,
>p.883).
Regardless, the empirical fact is that, genetically and morphologically,
many species differ from each other in ways that amount to collections of
microevolutionary changes, in the same kinds of ways we'd expect them to
differ if one species evolved via microevolutionary steps from the other
(or from a close common ancestor). This does not *prove* microevolution, of
course. It just makes ID theory pointless until there is some *positive*
evidence that macroevolution is not simply another word for multiple
microevolutionary steps. In short, it has to be shown that the idea of
macroevolution can be *relevantly* distinguished from microevolution. So
far, all we have are *assertions* to this effect. If macroevolution simply
*is* microevolution repeated a few times, ID theory loses its primary
alleged reason for being.
Since repeated (*cumulative*) microevolution is readily observable in the
lab and in Nature, just what *is* the point of ID theory? Are ID folk
claiming that there is some *limit* on the number of times microevolution
can occur on one genetic subtree? If so, what is the *evidence* that there
is any such limit, and just how many times *can* a genetic subtree exhibit
microevolution before microevolution comes to a halt? And just what is it
that forcibly prevents *further* steps of microevolution from occurring?
What *keeps* populations of one species from evolving into other species if
environmental conditions are favorable to such evolution? Why don't we see
horrendous and insurmountable *stoppages* of further genetic variations as
microevolutionary steps accumulate, and *regardless* of the biological
advantages that such further steps would provide for the organism and the
genomes involved? Why were humans able to breed (mostly by chance) broccoli
*and* cauliflower *and* brussels sprouts *and* cabbage from the same
initial plant? Why didn't the limitation on microevolutionary steps prevent
this from happening?
And, of course, if this can happen simply because people in different
places and times preferred to grow plants with more of some features and
less of others, why can't similar "selection" occur in nature, via climate,
predation, nutrient availability, and so on? Since pleiotropism and genetic
cross-linkages are obviously not enough stop microevolution in its tracks,
just what *does* prevent microevolution from going that one more step and
becoming macroevolution?
Without strong answers to the core questions here (such as what evidence
there is that there *is* a real limit on microevolutionary steps), ID
remains just another scientifically superfluous crackpot theory promoted
almost entirely for religious reasons.
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