dkomo wrote:
> Tim Tyler wrote:
> 
>>Another quotable bit:
>>
>>``Darwinian selection remains the only explanation for adaptive
>>  evolution - and it is arguable (I would argue) that most if not
>>  all the evolutionary changes we actually see in the macroscopic
>>  world (as opposed to those concealed among the molecules) are
>>  adaptive and Darwinian.'' - A Devil's Chaplain, p.85.
>>
>>I'm not sure about the "all" but I'm inclined to agree
with the "most".
>>
>>Drift may have something to say about small populations on islands
>>around speciation events - but it's probably a bit player in most
>>other places - as far as the *features* of organisms go (as opposed
>>to the makeup of their genes).
> 
> 
> Really?  You mean the fact that people have brown, green, or blue
> eyes, are short or tall, fat or skinny, beautiful or ugly, have red,
> black or blonde hair, are prone to get different diseases in old age,
> have different reactions to medications, have different physical
> abilities like being able to run for long distances, sing very well,
> be really strong, and so on and so on -- these are all the result of
> adaptations and natural selection?
> 
Why not?  Their ancestors have experienced different environments, so 
hte selective pressures will be different.  Add into the mix variation 
in the environment (which can help maintain polymorphism), and 
disruptive selection, we have plenty of adaptive explanations for the 
diversity we see.

Of course, drift may also be an explanation, but I believe that we can 
only separate out the contributions of the different causes empirically.

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
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