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RE: Dinosaurs to birds



John Bois wrote...
< Randomness and selection are close to antonymns.  Would you agree that 
artificial selection is not random?  Then on what basis is natural
selection random?  Is it just because we are too thick to perceive the
patterns?>

     Mutations that provide the raw material for evolution are random.  Changes 
in environmental circumstances (extinction of competitors, evolution of 
predators, climate changes) that result in selection pressures are random for 
all practical purposes because a species's genes have no way to predict how 
they will change.  Natural selection is a non-random process that acts on and 
is dictated by these random processes.  
     For example, imagine that in the middle of July a freak winter storm   
that you would never have dreamed possible dumps ten inches of snow and 
temperatures drop below freezing; for your purposes, a random, unpredictable 
event that needs to be dealt with.  You take all the clothes out of your closet 
and dump them on the floor; you have before you summer clothes, formal clothes, 
winter clothes, lingerie etc... a random assemblage.  However, your selection 
of which clothes you will wear is not random.
      Evolution is called a random, unpredictable process because the mutations 
and environmental circumstances that, to a large extent, determine evolution, 
are random and unpredictable, and don't always allow selection to act in what 
may seem like the most logical and predictable way.  For example, what if your 
closet has no winter clothes?  You may have to just pile on a bunch of summer 
clothes.  Evolutionary history is full of such ad hoc solutions.  Selection has 
to work with the mutations that are available to choose from, which may not 
necessarily be ideal; just good enough to survive, exploit a new niche, or 
whatever.
 
LN Jeff