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Re: Big = Old = Advanced?



John Bois wrote:
> I think we can make informed guesses from extant species.  Emus, and
> ostriches would seem to be germane at something like 7 weeks.  Bigger
> species would take longer of course. 

why?  Couldn't a larger species (than either emus or ostriches) afford
to carry the eggs till the eggs where in a very developed state, then
lay them with a very short incubation period?  Birds don't do this
because birds fly and even the ones that don't would still have the
mechanism to keep weight off the body by laying eggs at the earliest
possible time in the development cycle.  Why would dinosaurs need this
mechanism in the first place?  They never flew (DinoGeorge not
withstanding-dinosaurs were laying eggs before they <possibly> became
arborial)

> If this is true, I
> have not too much of an idea why turtles (as untended as they are) don't
> seem to have a problem with this.  

a lot of baby turtles die.  Some clutches have complete mortality.  Does
seem sort of suicidal and the species isn't doing to well.

> No, what I meant (but didn't express) was that it takes more to make
> a dinosaur than it does to make a turtle.  More complex motor programs and
> behavioral programs require more neuronal wiring.  

eh nope-genetically this doesn't make sense.  It takes the same parts to
make a chimp as a human, or nearly 98% identical parts.  Therefore 98%
of the embryonic development time is the same kind of mechanisms making
the same kind of parts-gestation is nearly identical between humans and
chimps.  This fancier mental system is DEVELOPED AFTER BIRTH in humans. 
So, genetically, these more complex systems do not have to be to be
developed while in the egg. (besides, in humans these develop with
stimulus, and there ain't a hell of a lot going on in an egg)
 
> > I would say that most dinosaurs I have heard of lay remarkably small eggs
> > in comparison to their body size.  In birds, the smallest egg in relation
> > to size belongs to the largest living bird, the ostrich, which may tell you
> > something, but I'm not sure what.
> 
> It could tell us that bigger eggs are relatively more expensive to make.

larger eggs take more material to make, not more necessarily more time
if given a larger laying species

-- 
           Betty Cunningham  
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