Re: Life's complexity: self-organization, evolution or both?

On Tue, 18 Sep 2007 01:59:24 GMT, Bill Morse
<wdNOSPAmorse@xxxxxxxxxxxxxxxx> wrote:

r norman wrote:

On Mon, 17 Sep 2007 03:03:43 GMT, Bill Morse
<wdNOSPAmorse@xxxxxxxxxxxxxxxx> wrote:

Perplexed in Peoria wrote:



(snip)

That may well be true, but organism complexity and ecosystem
complexity are completely different animals. NS (i.e. reproduction
and genetic inheritance) is central in explaining organism complexity.
But NS isn't much involved in explaining ecosystem complexity.

Arguable. One doesn't ordinarily think of ecosystems as having excess
reproduction. But they might be considered to have heritable fitness. I
don't think one should completely dismiss the idea of ecosystems
competing.

Ecosystems are MUCH simpler than organisms, and their evolution is
something even a physicist can understand.

This seems extraordinarily unlikely on the face of it. Ecosystems are
composed of a large number of organisms. All our experience with other
systems tells us that aggregations of large numbers of subunits results in
greater complexity than that exhibited by any of the subunits.

It depends on how you count "number of subunits". Also, the patterns
of interaction between units within an organism are quite intense
whereas those between units within an ecosystem are rather weaker.
Yes, if somebody catches and eats you, that might be considered
intense from your point of view. But you have to look at the
population and the probability of being eaten. The nervous and
hormonal control systems, not to mention the genetic regulatory
control systems, within an organism and within a cell are much more
deterministic.

While I grant that there is a difference in intensity of interaction, the
definition is not all that clear. How does one treat endosymbionts? Are
they part of the larger organism or are they and the larger organism part
of a mini-ecosystem? And how does one treat eusocial insects, remembering
that ants comprise a huge fraction of the organisms in many terrestrial
ecosystems?

My initial thought in support of Pip's idea that ecosystems might be simpler
than organisms was that organisms in ecosystems might behave
statistically - I think this is in line with your argument that
interactions between units within an ecosystem are relatively weak. But in
reflecting on real ecosystems, I just don't see that statistical methods
capture much of what goes on. For instance,I'm unaware of any statistical
treatment that captures the importance of capstone species.

<snip section on "evolution of ecosystems", covered in a separate
post>

It is quite true that the notion of an "individual" is quite fuzzy,
especially when dealing with obligatory symbiosis. A lichen (algae
plus fungus) is a good example. There are many colonial organisms,
perhaps the Portuguese Man-of-War being the best known. And the
notion of "individuality" in social insects is another real issue.
Complexity arises at all levels of organization and the close
interaction between the components of a complex system blurs the
distinction between the levels. You can say similar things about the
relationship between macromolecules and cell organelles, or between
cells and tissues and organs. Exactly what is the "functional unit"
when the function is distributed across levels?

I do think the important aspect making a "system" an entity distinct
from its environment is that the patterns of connection and
interaction between the components of the system are distinctly
stronger than between the system and external elements (the
environment). Biology is filled with such systems at all levels of
organization. I would rather not get involved in a pissing contest
deciding which is "better" or "more complex" or "more important".
They are all very interesting and worthy of study and are all part of
biology.


.

Relevant Pages

  • Re: Lifes complexity: self-organization, evolution or both?
    ... complexity are completely different animals. ... I don't think one should completely dismiss the idea of ecosystems ... of interaction between units within an organism are quite intense ... It seems to me instead that succession as well as such ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... complexity are completely different animals. ... I don't think one should completely dismiss the idea of ecosystems ... of interaction between units within an organism are quite intense ... there was for instance a natural succession of ecosystems ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... and genetic inheritance) is central in explaining organism complexity. ... But NS isn't much involved in explaining ecosystem complexity. ... One doesn't ordinarily think of ecosystems as having excess ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... and genetic inheritance) is central in explaining organism complexity. ... But NS isn't much involved in explaining ecosystem complexity. ... One doesn't ordinarily think of ecosystems as having excess ...
    (talk.origins)
  • Re: Lifes complexity: self-organization, evolution or both?
    ... I don't think one should completely dismiss the idea of ecosystems ... of interaction between units within an organism are quite intense ... statistical treatment that captures the importance of capstone species. ... there was for instance a natural succession of ecosystems ...
    (talk.origins)