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Re: crocs eating hadrosaurs (was Gr. 9 sci proj)
Tony Canning wrote:
> > Since mammals don't have the same fecundity problems as
> > dinos (after all, they only have to have one offspring to maintain
> > populations)...
> Unless I've misunderstood what John is saying, this seems to be looking
> at mammalian fecundity the wrong way round - surely mammals don't
> have small numbers of young because that is sufficient to maintain
> the population; this sounds like group selection theory which is impossible
> to justify. Mammals have small numbers of young because of the obligate
> parental investment required, both before and after birth.
Tony, I'm sorry, this is my second attempt to clear this up. What I
_said_ does sound group selectionist. What I _meant_ was that predation
levels are so low that low fecundity is sufficient to keep populations at
carrying capacity. A dinosaur, on the other hand, possibly had to
produce more offspring in order for an equivalent number to survive in a
similar niche. I suppose both of these strategies are valid (but see my
response to Bruce Thompson).