evolution of 'atomic' instincts

John Donald Collier jcollier at ariel.ucs.unimelb.edu.au
Thu Sep 19 10:30:54 EST 1991


Jean Piaget describes an interesting case. Shelless snails
in lakes in Switzerland generally are found in an elongated
form in placid waters. They are capable of taking on a rounded
form when moved to turbulent waters. This behavioural modification
allows them to survive better in the turbulent water. According to
Piaget, they then tend to produce offspring that have a genetically
fixed rounded from (over numerous generations). He argues that this
is a sort of neo-Lamarckian evolution, though of course it does not
violate any particular doctrine of neo-Darwinian orthodoxy. The
significant fact in this case is that it is the behavioural
plasticity, and the change in behaviour resulting from the change
in environment that permits the selection of the rounded form. So
in this case the excercise of the behaviour is causally relevant
to the genetic fixation of the rounded type.

Classical Lamarckianism it isn't.

-- 
John Collier 				Email: Collier at HPS.unimelb.edu.au
HPS -- University of Melbourne		  jcollier at ariel.ucs.unimelb.edu.au
Parkville, Victoria, AUSTRALIA 3052	Fax:   61+3 344 7959



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