Tim Tyler  wrote in
news:c2mel6$2hjk$1{at}darwin.ediacara.org: 

> Jim Menegay  wrote or quoted:
> 
>> The real question is whether a typical ecosystem, containing
>> organisms adapted under credible biophysical constraints, will
>> exhibit homeostasis. Clearly, every such ecosystem will not. [...]
 
 
> Lovelock suggested systems will spend a lot of time in a state
> of homeostasis - with *occasional* flips between states.  This
> seems sensible - since homeostasis represents the simplest type of 
> attractor that an ecosystem can fall onto.
 
> In /theory/ it would also be possible for an environment to get stuck
> in a stable feedback cycle - where it endlessly oscillated between
> some small fixed number of states.

> Lovelock's hypothesis is effectively betting that that is rare - and
> that simple homeostasis is the common case.  It seems like a fair bet
> to me - I also expect homeostasis to be the common situation - and
> what you would normally expect to see if you looked at the world on
> some randomly-chosen day.

I agree with Tim (except maybe on the stable oscillation cycle - I have 
to think some more about that) One of the hallmarks of stable ecosystems 
is that they maximize the rate of processing of energy into order. If the 
ecosystem is unstable, there is a significant energy source available for 
a new organism. If the new organism fits well with the other components 
of the ecosystem, then the ecosystem as a whole will increase in 
stability. If not, there are likely to be further changes in the 
community until the ecosystem self-destructs or becomes stable.  The 
point is that the more stable the ecosystem, the less room for invasion, 
so homeostasis will tend to "evolve".

Yours,

Bill Morse
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