Subject: Re: Pigs could flya - Reply   
Date: Sat, 25 May 1996 22:04:57 -0400 (EDT)


> The key word in what I said was intrinsic. I would agree that most of the
> time that one can find a simple physico-chemical reason for certain
> features, it would probably be the case that they did not arise adaptively.
> I see no reason, however, why that should be a hard and fast rule.

I see what you mean.  I wasn't proposing it as a hard and fast rule.
It's a question of balancing the contributions of various factors that
constrain evolutionary change.  Why invoke adaptation if a simpler
explanation exists?  Why invoke adaptation if there's no way to falsify
your assertion that the feature is an adaptation?  And a characteristic
can't be selected for or against if it doesn't exist, or can't exist.
  
> 
> I also think these ideas are very important, and are probably given less
> attention than they deserve. Please give us your definition/explanation of
> species selection. Lisa has categorically stated that there is no such
> thing as group selection of any kind.

I should have stopped by
the library before answering this, but on the other hand the problem here -
certainly with Lisa Rogers - isn't a lack of access to the literature,
but a disagreement with it.  If I remember correctly, species selection
is the theory that the differential survival of species sometimes depends
not on the fitness of individuals, but on characteristics of the species
as a whole: for example, the longevity of the species, or its distribution,
or the rate at which it gives rise to daughter species.  It's unrelated
to the fitness of individuals.  It isn't a form of group selection, as far 
as I know.

Paul


     --- from list marxism2-AT-lists.village.virginia.edu ---