Re: Eggs and skill differentials

[John Bois <jbois@umd5.umd.edu>]

Jeff wrote:  Species lay as many eggs as is needed to
keep the population stable under thier environmental conditions. 

John responded:
> >  It would be nice if this is the way populations worked.  Apparently
> >  though, _individuals_ work for their own selfish needs.  The needs of the
> >  group are "considered" only inasmuch as they forward the needs of the
> >  individual.  

NJPharris chimed in: 
> I'm not sure how this follows from Jeff's argument.  However, I think I will
> have to agree with Jeff here.  Any _individual_ that either wastes resources
> on huge numbers of eggs with no chance of survival or doesn't lay enough eggs
> that some survive will quickly be weeded out of the gene pool.

This is, of course, true.  I was merely responding to the appearance of
group selectionist ideas in Jeff's language.  Subsequent posts indicated
harmony in our positions.

 John wrote:
> >  That is birds ahve a skill differential (wings) between themselves and the
> >  mammals (for example). 

NJPharris replied:
> A number of birds (corvids, for example, and skuas) are nest predators over
> which the prey species have no skill differential.  Also, many bird nests are
> in trees, which leaves them open to predation from snakes and arboreal
> mammals as well.

Right.  Some birds rely on concealment.  Others rely on remote laying.
Some have a blend of the two.  Is it appropriate to say here that because
of their relatively large size and their relative lack of remote laying
ability, that non-avian dinosaurs were relatively less able to employ
these strategies.  They were, therefore, more likely to defend their
nests.  I am sure that many non-avian dinosaur species were
formidable defenders.