Dan writes:
> I am not an expert on evolution (far from it) but I have a
> hunch that relates to Hutchinson's quote and analogy about
> "the evolutionary play in the ecological theater".
Let me say that you can do no wrong by reading and memorizing G. Evelyn
Hutchinson, and especially his student, Robert MacArthur.
The metaphor I tend to use however invokes a different art form, that of a
movie. The study of ecology, which entails investigations into the totality of
the biotic interactions we find on earth, is like the last, current frame of a
movie that has been running at 24 frames per second for the last several
hundred years.
When we do ecology, we're looking only at the last frame of the movie.
Ecology is evolution in "now" time, captured in the current frame, but no
matter how
intricately we tease apart the ecological physics of those interactions in
this last frame, the interactions will never make complete sense unless they
are
examined over the course of the entire movie.
The "ghosts of competitions past," where pronghorn antelope run at high speed
from a cheetah that's no longer present on the North American plains, is as
good an example as we have of the necessity of imposing time into our studies,
making Hutchinson's "the evolutionary play in the ecological theater" phrase
all the more relevant.
Why are developing these metaphors important? On one hand, saying all of this
is obvious. On the other, these discussions have almost no practical value
when you're in the field, taking detailed measurements. But "science" doesn't
mean "data." The mathematician Henri Poincare wrote, "Science is built of facts
the way a house is built of bricks, but an accumulation of facts is no more
science than a pile of bricks is a house."
"Science" literally means "understanding," and without developing these
perspectives, we really don't understand much of anything. Evolving truly
accurate
mental metaphors and models is fundamental to doing science, of any stripe.
Saying this, what then of the idea of the "evolutionary algorithm"? In that
regard, you write:
> My hunch combined with your analogy below of "evolution as
> algorithm" might be considered "ecology as operating system".
> This focuses on ecology at the ecosystem and biosphere level.
> Your description of the algorithm seems to explain and
> characterize selection well, but it does not seem to account
> for 1) generation of novelty, other than via random or
> error-related mutation, 2) feedbacks that result when the
> organisms and communities/ecosystems alter the environment
> and then have to adapt to their own alterations (as studied
> in "niche construction" and "ecosystem engineers") and
> 3) the infrastructure and maintenance of elements, energy,
> materials that make the instantiation or materialization of
> new forms ("actors") possible, participates in juxtaposing
> them in new "plays" and "cleans up the mess" after the "play"
> (i.e. decomposition and recycling) so that the "theater" is
> not cluttered from past performances. I could convert these
> to algorithm or application/program vs operating system
> examples relation to hardware realizations, memory and/or
> disk space/clutter.
>
> Algorithms are great, but for them to work one needs an
> operating system that can continue to "run" and allow many
> "programs" to "run" and that is robust and does not itself
> "crash". There is also work by folks following up on Robert
> Rosen that suggests that much of the essence of life process
> is non-computable, not algorithmic and non-mechanistic. Some
> of the work here focuses on ambiguity and circularity, both
> of which algorithms do not handle well but life seems
> accustomed to.
I previously wrote the evolutionary algorithm as:
"Given self-reproduction, Darwinian evolution is composed of only these five
components:
o a bounded arena
o a replicating population which must eventually expand beyond the
bounds of the arena
o thermodynamically inescapable replicative error, guaranteeing
variation within the reproducing population
o competition for space in that arena among the inevitable variants
o the consequential competitive exclusion of the lesser fit"
But it's important to note that Darwin probably would have said the same
thing, if the word "algorithm" had been in use 150 years ago. What he did
write,
in the final paragraph of his last chapter in "The Origin of Species," was this:
"It is interesting to contemplate an entangled bank, clothed with many
plants of many kinds, with birds singing on the bushes, with various insects
flitting about, and with worms crawling through the damp earth, and to reflect
that these elaborately constructed forms, so different from each other, and
dependent on each other in so complex a manner, have all been produced by laws
acting around us. These laws, taken in the largest sense, being Growth with
Reproduction; inheritance which is almost implied by reproduction; Variability
from the indirect and direct action of the external conditions of life, and
from
use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life,
and as a consequence to Natural Selection, entailing Divergence of Character
and the Extinction of less-improved forms. Thus, from the war of nature, from
famine and death, the most exalted object which we are capable of conceiving,
namely, the production of the higher animals, directly follows. There is
grandeur in this view of life, with its several powers, having been originally
breathed into a few forms or into one; and that, whilst this planet has gone
cycling on according to the fixed law of gravity, from so simple a beginning
endless forms most beautiful and most wonderful have been, and are being,
evolved."
This is one of the most quoted paragraphs in all of biology, but the feeling
I get when I see it repeated is that most people are using it merely as a
poetic description of his ideas. I don't believe Darwin meant it to be taken
that
way.
If you're going to read Darwin, you must first understand that beyond his
being a superior observationist, he was a hard-nosed mechanist, as much as any
physicist or engineer. He wanted to understand process and mechanism, and in
doing so, gave evolutionary theory for the very first time a very clearly
defined
physics.
I've written before here that we're not doing ourselves any favors by saying
that "ecology has no laws." More than that, I believe the sentiment to be
nonsense. When I look at nature, I see nothing but rules, where Darwin's
physics
merges seamlessly into the ecological physics of competitive exclusions,
carrying capacities, faunal relaxations and the like.
If Darwin lived today, in a modern world of bullet-pointed PowerPoint slides,
his last paragraph would probably look like this:
o Growth and Reproduction, and by consequence, Inheritance
o Variability in form
o Ratio of Increase leading to a Struggle for Existence
o Natural Selection as a consequence
o Leading to Divergence of Character
o And the Extinction of less-improved forms
This is the Darwinian algorithm, as explicitly outlined by Darwin himself.
If this is truly an algorithm, who or what then is doing the processing?
Nature, of course. Given self-reproducing entities, the Darwinian algorithm is
the
inescapable consequence of reproduction in a positively entropic, bounded
universe.
Finally, as long as we're on this paragraph, let me speak to one other,
unrelated item, one that deals with Darwin's phrase, "There is a grandeur in
this
view of life," a sentence which is also often quoted.
My own idiosyncratic reading of these last few sentences is that he was
speaking primarily to himself, trying to salve his conscience for the physics
he
was proposing, a physics built on death, disease, famine, pestilence and
predation. To do that, he wrote an extremely uncomfortable truth: "Thus, from
the war
of nature, from famine and death, the most exalted object which we are
capable of conceiving, namely, the production of the higher animals, directly
follows."
I personally feel the same way. In any universe that I would build, there
would be no death, no aging, no sickness or war. The only rub is that I have no
idea how such a world could either come into being or how it could be
maintained. In Darwin's alternate universe of death and famine, we
unfortunately have a
simple, easy-to-understand mechanism, one that does eventually builds the
most exalted objects which we are capable of conceiving, the production of the
higher animals.
Wirt Atmar
