[Taxacom] barcode of life: PS

Curtis Clark lists at curtisclark.org
Mon Jul 5 09:41:27 CDT 2010


On 7/4/2010 9:37 PM, Stephen Thorpe wrote:
> The point is that IF the human height frequency distribution was flat 
> (which it isn't), then the concept of short/average/tall would have 
> less "reality" than it actually does, and could only be purely arbitrary.
I agree that it would have less "reality". I agree that it would be 
"arbitrary". Where I disagree is the idea that the actual perception of 
the actual distribution is not arbitrary. I pointed out a reason why I 
think a bell curve causes us to perceive the tails of the distribution 
as exceptional.
> On the other hand, if everybody were to die out except for a narrow 
> band around the average and at each extreme, then the 
> short/average/tall distinction would be far more real than it actually 
> is.
Of course.
> As it is, it is not completely arbitrary, but not that good either.
We evidently disagree on "how it is".
> So, similarly, the reality of species distinctions depends on what is 
> out there in the world. If reproductive isolation is mostly either all 
> or nothing, then species are very "real". If it is mostly 50% (or 
> random) then species do not represent reality very well at all. I say 
> it is pretty good. Rich seems to disagree, and says things which 
> sometimes suggest complete arbitrariness (like shortness on a flat 
> height distribution) ...
Perception is based on phenotype, which responds not only to gene flow 
but also to selection. And, as I've pointed out, perception does not 
always reflect "reality".

-- 
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Director, I&IT Web Development                   +1 909 979 6371
University Web Coordinator, Cal Poly Pomona





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