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Re: harmony in nature...what I meant



> "David Marjanovic" wrote [offlist... never mind]:
>
>  > "No, I can't. Please explain. :-) What do you mean by harmony in
nature? What exactly do you mean by ecological niches?"
>
> What I mean by "harmony in nature" is basically the way things go. Not
that there is a certain "plan", but rather the way things go are the way
they go, and I think eco niches exist because of the animals which are
there. A wolf in Yellowstone serves a very important niche to keep down deer
populations. We know that specifically because when we took the wolf out,
the deer overpopulated.

yep

> That is what I mean by harmony. The wolf is "needed" to fill the niche.

Hm. When there are big plant eaters, and animals that can evolve into big
meat eaters, then the latter will probably happen sooner or later. But it
isn't actually forced to happen, just the possibility that it happens is
high.
        Look at Mauritius -- did the dodo have any "natural enemies"?
There's another way to keep population sizes constant: to evolve K-strategy,
e. g. to lay only one big egg each rare time rather than 12 every few
months.
        Look at elephants. Since the saber-toothed cats died out, hardly
anyone eats them. No problem, elephants only get one young at most every 2
years.

> [...] I'm saying that, if you take out a valuable element to an ecosystem,
you will obviously have consequences.

But if it has never been there...

> That is why animals are needed. That is why they are important.

I can easily imagine a world without _any_ animals... there were none for
most of Earth's history :-)

> Isn't that what evolution is about?

Nope. Evolution is the almost circular outcome of 2 facts:
1. Mutations occur.
2. Those that get more surviving offspring, due to whatever mutations, get
more surviving offspring. The next generation will to a greater part be
composed of offspring of those that got more surviving offspring. This is
already the simplest form of natural selection. :-) Now kill off some (a
more usual form of natural selection), and with a considerable probability
only offspring of those that had more surviving offspring will survive.
        Usually it gets much more complicated (what if the less
effectively-fertile ones are much better at hiding from predators...), but
at the simplest level, evolution is _amazingly trivial_.

> Given time, I am sure another predator would fill the boots of the wolf,
but not without the system experiencing problems.

Well then the system _does_ experience problems. (Up to a mass extinction,
theoretically at least.) Who cares? :-)

> That is what I am saying. It really isn't that difficult to fathom.

It is, its bottom isn't stable. :-)