Function, Symbiosis, Parasitism

["Tim Gwinn" <***>]

I have been somewhat incapacitated this last week, but am finally feeling
better. During my forced rest, I tried to further some earlier thoughts on
symbiosis & parasitism. Mainly I was wondering about the question of
"improving" our (human) interaction with the biosphere; loosely, "how do we
become more symbiotic and less parasitic?", along the lines of an earlier
remark by Judith. Of course, that leads to asking what "more
symbiotic"/"less parasitic" means.

This has proved more difficult than I expected. Ultimately, notions like
'symbiosis' and 'parasitism' characterize certain functional relations
between organisms(i.e., no creature is a symbiote or parasite in isolation).
Further, if we move from discussing individuals to discussing generations of
individuals, then the notions of fitness, adaptive behavior, and so on,
changes. There seems to be little in the way of first principles or
absolutes to rely upon; instead, all these notions are relative to some
context.

If we look at two individuals of two species of organisms as systems, S1 and
S2, then we can ask: what happens when S1 interacts with S2? Or, in the case
of  two organisms sharing one environment or ecosystem (E), then we can ask:
what happens when S1 and S2 both interact simultaneously with E?

In a Newtonian universe, we could say that systems S1 & S2 & E are
individually described by some fixed mathematical description f & g & h,
respectively. Further, in this mechanistic universe, we can in principle
describe the systems along with the interactions between these three systems
(S1 + S2 + E) by some larger mathematical description j. In doing so, we
have assembled everything together into one large mechanical system. The
individual systems (organisms), now swallowed into the mathematical
description j, have lost their identity and accordingly, there is no longer
any need to think in terms of any notions of "function" occuring between
those individuals. Instead, we can talk in terms of state descriptions of
the larger system. Or, we can retain the individual systems as distinct, and
just assume that it is entirely valid to describe the interactions between
S1, S2 and E via mathematical descriptions. (In this case, j is tacit, and
any failures in the mathematical descriptions are always considered fixable
by some "better" model, yet to be discovered).

However, if S1, S2, E are complex in the Rosennean sense, then the complex
systems cannot be described by some fixed mathematical description.
Therefore, the interactions between the complex systems will be complex.This
further means that there can be no overarching mathematical description j
which describes (S1 + S2 + E). In this case, we have to take those systems
and the interactions or relations between the systems as irreducible.

But what makes those relations "functions"? As Rosen describes in Life
Itself, "function" is a way of describing a part of a system: remove the
part from the system, and the discrepancy in behaviors of the system between
when the part is removed and when it is present characterizes that part's
(or "component's") "function".[LI 115-116]

In other words, 'function' is not merely about the mechanics of the
interaction, but instead it is about the interaction in the context of some
larger system - in this case (S1 + S2 + E). So, to say that "species P & Q
are in a predator-prey functional relation" is to really say: "in the system
(P + Q + E), species P & Q are in a predator-prey functional relation". (For
example, think of an alternate ecosystem E' where the "prey" Q occupy areas
also occupied by another species R (as part of this ecosystem E') which
would be fierce predators of P, and therefore "predator" P does not hunt
"prey" Q in E'.)

So, if we ask about two species X and Y as symbiotes, we are asking about a
functional relation between X and Y via environmental interaction. So that
means we are asking about functional components X and Y as symbiotes in a
given ecosystem E. That is, is X performing a symbiotic function with
respect to Y, and is Y performing a symbiotic function with respect to X, in
the context of a certain E?

Of course, there has to be a way to characterize the term "symbiotic", and
Rosen does this in general mathematical terms in 'Cooperation and Chimera'
in EL. Similarly, parasitic relations can be described in general terms as
he does in AS. (Both of these roughly follow the commonsense meanings of
these terms.)

There are so many questions at this point, so many possible directions to
go. For example, suppose X & Y form some strong symbiotic relation. Suppose
also that Y is in a parasitic relation with Z, that may ultimately lead to
the demise of Y. In this case, X's survival may also be in jeopardy if it
depends too strongly on Y. In such a situation, there is nothing inherent
about components E, X, Y or Z that is "bad", it is simply a result of their
contextual relationships. (In the spirit of Hamlet: "there is nothing either
good or bad in a functional component, but the contextual relationships make
it so.")

Importantly, there is nothing inherently good or bad about the specific
behavioral *mechanisms* that a species might have. What is important is how
the species performs in a functional role. There may be many possible
mechanisms that will lead to a similar functional role.(Rosen discusses
this, if I recall correctly, in relation to evolution in AS.)

When we expand into thousands and thousands of species, it seems
mind-boggling: they are all interacting indirectly via the environment (to
one degree or another), and in so doing they are *cultivating* that
environment, making changes in some cases to it, and in other cases
providing some kinds of stabilizing effects. Some species may also be
interacting directly. How do we begin to describe this? (Recall that systems
in isolation do not provide the information needed - they need to be
observed in their functional context.)

And if we shift from individuals in species to an evolutionary perspective,
considering the generational trail of a species as the "individual" under
study, then relationships that appeared symbiotic may now appear parasitic,
particularly if the species have widely different generational timeframes.
And in this evolutionary perspective, it would be unusual if E had no
notable changes, which in turn will affect the species in that ecosystem,
etc.

When are we humans guilty of wiping out a species? When it is a passenger
pigeon, Tasmanian tiger, etc.
When are we humans "successful" at wiping out a species? When it is polio or
SARS.(At least, that is our goal.)

How do we characterize this value judgement? And, how do we then make policy
generally about the biosphere, and our place in it, given these kinds of
considerations?

Regards,
Tim



> -----Original Message-----
> From: ROSEN Forum [mailto:*** Behalf Of Tim
> Gwinn
> Sent: Monday, June 23, 2003 2:49 PM
> To: ***
> Subject: Re: Anticipatory behavior
>
>
> Yes, but in the that word "health" resides the real difficulty.
> Healthy for
> who? Healthy in what way? And so on. In particular, he discussed
> the ways in
> which fitness of adaptations on an individual level and adaptations on a
> evolutionary scale, even within the context of a single species, diverges:
> "Conceptual difficulties with evolution have always grown from
> the fact that
> the two need not coincide." (EL p. 322)
>
> I imagine that if we were to promote one kind of relationship in
> a way that
> we could measure as being more symbiotic than parasitic, then it is likely
> that the resulting increase in symbiosis will have some deleterious effect
> on some other organism. Even worse is that the biosphere at large
> is, by its
> nature (no pun intended), home to constantly evolving (on differing
> timescales) organisms such that the overall system - the one which we want
> to become more symbiotic with (using predictive models and anticipatory
> behavior) - is ever-shifting.
>
> I don't think this makes any attempt to live more symbiotically
> impossible,
> but it does make the criteria for 'success' in that regard much more
> difficult to gauge, in my view. Specifically, I have always been reluctant
> to consider such symbiotic success to be measured as the degree
> to which an
> ecosystem remains unchanged, primarily because an unchanged
> ecosystem is, in
> my view, a kind of short-term parasitic timescale view, rather than a
> longer-term global (evolutionary) timescale.
>
> In the global evolutionary timescale view, an altering of an
> ecosystem seems
> to me unavoidable unless we deny all evolutionary capacity of the
> organisms
> therein (and nearby). But I do not think most ecologists would favor this
> view, although it seems inevitable to me.
>
> Regards,
> Tim
>