Re: Big = Old = Advanced?

[Jeffrey Martz <martz@holly.ColoState.EDU>]

> >      What makes you think it is?  Species lay as many eggs as is needed to
> > keep the population stable under thier environmental conditions.  What
> > makes you think the dinosaurs were not laying exactly as many eggs as they
> > needed to make up the difference?
> 
> 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.  

     If the individual lives in an environment with high predation, it
will "selfishly" produce more eggs to compensate for the loss to get its
own genes passed on.  But, if the number of progeny produced is too large,
the population size exceeds what the environment can support.  It does
little good to get your genes passed on if your progeny all die off from 
starvation in the next generation.  Consequently, a certain balance is
needed.  Also, each species livingh in its own environmental conditions
may have a most effective balance between number of progeny and degree of
development &/or degree of care of the progeny, and exceeding that balance
in one direction or the other may place an unrealistic strain on the
parent's resources.  Producing both LARGE and NUMEROUS offspring
require an unrealistically  large investment from the parent, either in
time or resources.   Obviously, producing a FEW, SMALL
offspring would place them at great risk, so again there needs to be a
balanace between what the parent can feasibly produce and protect, and
what can survive.    
     
> >      I'm afraid I don't know what "skill differential" means.  I have been
> > out of the loop for a while and this discussion may have gone in new
> > directions.  Could you please explain a little more?
> 
> Birds can fly away to places of reduced predator density (and swamp the
> few predators that are there).  Dinosaurs had no particular skill
> differential which would enable them to put such huge distances between
> themselves and those other dinosaurs which would eat them.

     Clams live in a predator rich environment, and needless to say
aren't going anywhere.  They compensate for this by producing a HUGE
volume of eggs.  Sea turtle hatchlings deal with devastating predation
both on the beach and in the water.  Escaping to areas of reduced
predator density is not an option for numerous animal species, and high r
reproductive strategies are an effective way of dealing with it.

LN Jeff
O-