evolution of 'atomic' instincts

Alan R. Rogers rogers at ANTHRO.UTAH.EDU
Thu Sep 19 09:36:25 EST 1991


> How is the evolution of 'atomic' instincts explained?
> By 'atomic' instinct, I mean a complex instinctual
> behaviour such as constructing a beehive.  The initial
> advantageous mutation must be how close to the fixed
> evolution-selected instinct?  Did the construction of 
> beehives start with a bee with a mutation that just
> caused it cough up a lump of wax?  An amorphous behavioural
> mutation too far from the finally selected stable instinct 
> seems unlikely to converge to the final instinct no matter
> how many generations pass.  It's clearly not magic or divine
> intervention that does it, but could there be some
> lamarckian channel that allows for accidentally performed
> proto-behaviours to be incorporated into the genome?????

This argument goes back at least as far as a 19th century book, Natural
Theology, by William Paley.  It is made most often with respect to the
vertebrate eye, which is claimed to be useless until fully developed.  That
argument is not convincing any more, because comparative morphologists have
discovered a whole series of functional eyes ranging from simple spots of
light sensitive pigment through eyes like yours and mine.  Another favorite
is the elephant's trunk.  What use is a 3 inch trunk?  The answer became
clear only after the elephant's ancestor was found to possess a shovel-like
lower jaw.  The trunk apparently began as an extension of the upper lip that
pushed food along this extended lower jaw into the mouth.  I don't know
anything about beehives, but I'd be willing to bet that some analogous
explanation applies there too.  Issues of this sort are discussed at length
in Doug Futuyma's excellent book SCIENCE ON TRIAL: THE CASE FOR EVOLUTION.




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