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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004><FONT
color=#800000>You are assuming, of course, that the penis size is regulated by a
standalone gene. Penis size could easily be caused by genes that share control
with other features as well. Butts could be the same way. Not every phenotype
has to have it's own selection pressure. Many complex traits have phenotypes
which can ride along with others since they are all sharing various alleles.
These combinations can create situations where certain phenotypes appear in
conjunction with other phenotypes on a fairly regular basis. As long as
their cost does not outweigh the benefit of other features that come with
it, the frequency of that phenotype will increase.</FONT> </SPAN></FONT></DIV>
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class=851074504-01122004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>Kevin
Freels</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=851074504-01122004></SPAN></FONT> </DIV></SPAN></FONT></DIV>
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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>Take
the penis. (No, not THAT definition of take, dammit, pay
attention.)</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>Its
survival cost to benefit ratio Rs is surely larger than 1. But
its</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=851074504-01122004>mating attractiveness cost to benefit ratio
Ra is less than 1. So</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>we
can multiply the two ratios together to get an overall
evolutionary</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>cost
</SPAN></FONT><FONT face=Arial color=#0000ff size=2><SPAN
class=851074504-01122004>to benefit ratio. If that overall ratio is
greater than 1,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851074504-01122004>we
might expect that structure to evolve smaller.</SPAN></FONT></DIV>
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