From: Ray Recchia (rrecchia@mail.clarityconnect.com)
Date: Sat 03 May 2003 - 13:34:36 GMT
I'm reading "Darwin's Cathedral" by David Sloan Wilson and I have a general 
evolution question.  Suppose a species initially evolves under 
circumstances where there is an advantage to having a drab grey color to 
provide circumstances.  Then suppose circumstances change so that spot 
provide more of an advantage.  Over time the species evolves an elaborate 
biochemical mechanism for spots that allows the species to survive 
effectively in this new environment.  Next suppose the environment changes 
back so that drab grey is now more effective.  Organisms can go back to 
drab without unevolving the entire mechanism for spots.  Instead they can 
just have point mutations that disable the spots.  Then if the environment 
changes again so that spots are better, instead of re-evolving the whole 
spot system again, all that is necessary is that a few individuals lose the 
point mutations preventing spots from being expressed.  This means that 
spots can reappear much more quickly the second time than they did the 
first time.
So my question is, are there any real examples of this occurring in 
nature?  Is there a term that is used to describe this phenomenon? 
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