Re: Earth's Carrying Capacity
From: Sander Vesik (sander_at_haldjas.folklore.ee)
Date: 08/27/04
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Date: Fri, 27 Aug 2004 20:15:10 +0000 (UTC)
In sci.space.policy Fred K. <freddo411@yahoo.com> wrote:
> "Pete Lynn" <pete@peterlynnkites.com> wrote in message news:<1092958526.881712@kyle.snap.net.nz>...
> > "Fred K." <freddo411@yahoo.com> wrote in message
> > news:a3485e71.0408191235.3ca7d77@posting.google.com...
> > >
> > > For example, consider North American 20 million years ago vs.
> > > NA 500 years ago. NA @2000K BC had saber-toothed tigers,
> > > woolly mammoths, and other land animals that became extinct by
> > > NA 1500 AD. One state of the ecosystem was replaced by a
> > > different state. Consider; which state was better or worse? Why?
> > > What criteria would one use to decide?
> > >
> >
> > Arhh, I thought these extinctions, (mammoths, lions, saber-toothed
> > tigers, cheetah? large sloth?), occurred some 11000-8000 years back,
> > coinciding with the significant arrival of man. Not that I disagree
> > with your point, but I suspect you might have picked a better example.
> >
> > Pete.
>
> Thanks for the correction. I should have said 20000 BC not 20 million
> BC.
>
> I don't know if the conventional wisdom favors a) human hunting, b)
> climate changes or c) introduction of eurasian species as the dominate
> cause of the extinctions. I'm open to suggestions.
IIRC, the mammoths survived on Wrangel as long as at least 3000 BC,
possibly longer.
>
> For some purposes, I think it would be good to have as an example an
> ecosystem that differs significantly from era to era that definitely
> didn't have humans as a factor. This might be more compeling in
> getting the point across that ecosystem change is a usual, natural
> thing.
>
> On the other hand, North America's natural history is well known
> enough that it makes a handy example. Having pre-industrial humans
> involved can be a plus as it shows they are part of the ecosystem.
Or not. There are good examples in Australia of species that were
definitely kileld off by such with the use f hunting and fire.
-- Sander +++ Out of cheese error +++
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