(fwd) Re: ecosystems

Onar Aam (onar@HSR.NO)
Tue, 29 Aug 1995 12:16:23 +0100


forward to pcp

> I agree that ecosystems shows signs of organizational closure. In
> fact, Varela (one of the autopoiesis inventors) has theorized that
> autopoietic systems belong to a larger class which he calls
> "organizational closure". This broader term does not require a
> definite boundary nor component production. Ecosystems definitely fits
> into the category of organizational closure, but is there a definite
> boundary?

Usually there are no definit boundaries, there is alwaqys some
migration, etc

Component production? If there are then they certainly are
> not staring us in the eye. I have problems imagining an ecosystem
> having a clearcut boundary, and what are the components that the
> ecosystems supposedly produce?

The tric with ecosystems is that they do nothing [it is a concept,
rather arbitrary]. An ecosystem is a
bunch of populations with the physical-envirnment, etc etc. The
organisms do things. But of course there are matter-cycles, there
are energy-cycles or streams, there are interdependend niches, etc,
etc. I f anything would be self-produced, it could be found in the
discussions about resilience, stability, et6c. . See for instance
Pimms S L (1984) The complexity and stability of
ecosystems. Nature vol. 307 26 january, 321-
326.
Above the population level you could say that structure is produced,
in that sense that species fight back if you trie to destroy a
structure. Fighting back could mean that species adapt to changes,
etc [on a long timescale, when big organisms are concerned].
Or it could mean that open spaces will be inhabited again, or that
new niche -space created by the disturbance is filled, or that
species stay put if change brings them out of the conditions they
thrive in.
The big difference between organisms [they are different too,
compare a bactery with a tree with a dog] to and ecosystems is mainly
that organisms are reproduced in one blow: from one cell to a new
individual [but then again what about vegatitive reproduction with
plants].

The main thing I learn from this is that we have a lot of concepts
that thrive [nice word:-)] when they are connected to something we
can really see or experience, but that comparing them on theoretical
grounds is really hard: we constantly find exceptions, etc.

greetings,

These questions needs to be given good
> answers before ecosystems can be deemed autopoietic.
>
>
>
> But apart from this a strong case can be made for autopoiesis, even
> when it comes to the boundary. Ecologists have noted that more mature
> ecosystems are more resistent to colonization of new species than young
> ecosystems. This definitely resembles the organizational homeostasis of
> autopoiesis.
> The ecosystem may be seen to compensate for the deformations
> (invasion). I'm not sure, but I believe that the extension of an
> ecosystem in many cases is bounded (i.e. a forest, an island, a
> valley), either sharply or fuzzily. We may speculate that ecosystems
> need "help" from their physical environment in order to be able to
> create such a boundary. This, if true, suggests that some ecosystems
> that grow in "convenient" places will turn autopoietic, while other
> more openended ecosystems will remain just dissipative. (I'm all along
> assuming that the food-webs of ecosystems somehow make up the
> autopoietic component production network). This is all very
> complicated.
>
>
>
> Onar.
>

Theories come and go, the frog stays [F. Jacob]
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