From: bivalve (bivalve@mail.davidson.alumlink.com)
Date: Wed Aug 13 2003 - 13:29:01 EDT
>I agree that all of these (and ones offered by Terry) affect evolution, but I don't see most of them as alternatives to natural selection. For the most part they introduce variation and then natural selection filters out the ones that are not useful for survival. Catastrophic changes are an exception and certainly would represent a non-"Darwinian" effect.<
The intensity of natural selection is quite variable, both in time and space and in the particular characters affected. Overall, natural selection filters mainly features that are harmful to surival (under the selection pressures of the moment) rather than useless but harmless features. Also, in many cases (probably the vast majority) there is no one best solution. What is actualized is very much affected by the other factors, even though natural selection provides some boundaries.
Dr. David Campbell
Old Seashells
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Box 870345
Tuscaloosa, AL 35487-0345 USA
bivalve@mail.davidson.alumlink.com
That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa
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