Re: Nature magazine article- On niches and neutralities - a bit more

[John Kineman <***>]

Regarding agent based modeling using niche suitabilities:

JR:

> As far as I am able to follow this, I see no statements that concern me in
> terms of "RR's" ideas. By what definition do they use the word
> "suitability"????? Isn't the concept of function creeping in there? How do
> they explain the process by which a plant, say, "modifies its own
> suitability factors as it goes"? How do they explain the method by which a
> plant sets its suitability factors? And how do they justify the inclusion of
> a concept of function here and the exclusion of the same concept elsewhere
> in biology?
JJK:
This is what I am currently researching and trying to develop, so I'm
very much trying to build in the functional concepts. A niche is a
functional relationship in my view. It does not say: "the organism is 3
meters long and so it's niche is a 3-meter cave" i.e., a strictly
structural definition, it should properly say: "the functional
requirements and behaviors of the organism lead it to utilize resources
in this way." That is a better statement but still a rather static idea
of what the function does and how it interacts with the physical
variables. Functional complexity at best shows up as uncertainty in a
niche model. But by making it iterative I can also make its definition
adaptive to changes in function or conditions, and I can introduce the
"impredicative loop" between a map of suitable conditions and how the
organism modifies those conditions. It is a very small step toward true
complexity and is still a mechanistic simulation; but its the best I
know how to do right now. The key is to make it highly adaptable and
repeatable so that we can use it in a complex manner, as in adaptive
management. Then it is a tool that helps us track complexity, rather
than a model of complexity. This is my approach at the moment.

JR:

> "What if the niches are
> changing faster than evolutionary adaptation?" I think the organisms that,
> under those circumstances, have behavioral adaptiveness options in addition
> to their evolutionary model are likely to survive much better than ones that
> are stuck  with only their evolutionary model.

JJK
Yes, I fully agree, and its not unscientific at all. That's probably why
we evolved brains that amplify this functional relationship in real
time. It has more advantages than disadvantages (as we all know from
experience it has both).

JR:

> In other words, the organisms
> that could adapt their behavior to compensate for their model being
> "sub-optimal" for the new conditions were the ones that survived to evolve
> into the organisms of our current planetary ecosystem.
JJK:
You have just stated the main argument in James Mark Baldwin's "a new
factor in evolution" which became coined "The Baldwin Effect" and then
essentailly forgotten for 100 years.

JR:

> I believe that's
> exactly what happened with the last mass extinction. Some climatalogical
> insult (be it an asteroid or volcanic or whatever, in origin) caused an
> immediate period of extreme climate fluctuation/change before equilibrium
> set in again. Organisms that could move around, or send their seeds around
> could avoid certain dangers. Organisms that could go into "stasis"
> (hibernation) could wait it out. Organisms that could utilize alternate food
> sources without negative consequences or that could utilize alternate modes
> of reproduction (asexual or parthenogenetic forms) would keep their species'
> populations up and,thus, out-compete other less-gifted organisms for limited
> resources, etc. So those organisms would have an edge in such adverse
> environmental conditions. The same will be true if/when it happens again. In
> fact, I think it is already happening. What was that number Dan quoted for
> how many species are going extinct yearly now? The organisms with the most
> rigid requirements and the fewest options are the ones that can't survive
> change.
JJK:
I quoted 11,000 a year going extinct, a number I got from a recent
conference on the topic hosted by the Smithsonian.

On the extinction hypothesis -- You may recall from basic ecology the
idea of "R and K selection" from McArthur and Wilson's Island
Biogeography theory. R-selection is selection for generalists, which
maximize seed production and, while inefficient at using local
resources, are good at using a broad range of resources. K-selected
organisms are those that are specialists. Energy is put into specialized
use of resources, lower reproduction, etc. Specialists can usually
out-compete generalists if local conditions are stable, although
invasive species seem to fly in the face of this simple concept. Anyway,
my point is these are functional types based on life strategy. It also
applies to predator strategies, e.g., "sit and wait predators" vs.
"widely foraging predators" One conserves energy and toughs out the
famines, the other expends energy to go looking, but then has less time
to find something. Which strategy is best? Its a functional relationship
with the surroundings, the larger system and an example of functional
complexity.  Accordng to R-K selection theory, generalists will colonize
during times of change or disturbance, then gradually evolve into
specialists and migrate to the core of islands. So you should find
generalists at the edge and specialists at the core. Specialization to
stable conditions increases risk of extinction, so they calculated
extinction probabilities based on this idea. Mountain gorillas, for
exaple, are highly specialized creatures and now inhabit an area that is
less than 500 sq.km broken into two pieces and there are only 400 of
them left. Coyotes, on the other hand, are doing fine in many parts of
Los Angeles in addition to the wild (or perhaps that is the wild).
Unfortunately the theory never advanced beyond some simple mathematical
rate calculations and with the skepticism about competition theory
increasing, many have moved away from it. It is obviously true in many
cases, but much more needs to be considered and the foundation needs to
be re-examined in terms of a broader functional theory. But I am still
convinced they were on the right track. It was a case of then trying to
make it look like physics and putting the mathematical models first,
rather than fleshing out its own foundations.