[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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