Distribution of species:
There is a recent article (A Theoretician Ponders what Physics Has to Offer Ecology, Aaron Clauset NATURE vol. 465 no. 7295 May 13, 2010 page 139) which describes work by James O’Dwyer and Jessica Green of the University of Oregon that successfully describe the distribution of species using, get this, a model from the mathematics of quantum field theory. You may not feel intimidated, but I do. Quantum mechanics, or course, depends on systematically describing inherently random events. So there is a random (sexy word: “stochastic”) underpinning to the model. My own computer model, with which I am still not completely content, also has a random function. But it is on the order of “thus many chances out of thus many each generation at these sites that there will be a change.” It is a far cry from modeling spherical harmonics, which is where the distribution of charge likelihood around a nucleus is coming from. My patient organic chemistry professor once spent about twenty minutes going through a single quantum equation for us, and for about two minutes I really thought I understood it.
Still and all, it is a purely random formula that appears to explain decades of field work and resolve apparent conflicts in observations of species density in given areas. That much we can claim in common; my model even in its present imperfect state also describes a lot of field work.
My interest is of course in population size and fertility. These people are talking about speciation. But it is sort of like peering over to see what’s going on in the next pew. Not really polite, but you feel like you ought to know. If I had the courage I would write the bold physicists and see if we could understand each other. But I can’t really say what I’d ask. I just have this feeling that there is a common thread.
Another article (Matters of Scale, Brian J. MeGill SCIENCE vol. 328 no. 5978 April 30, 2010 page 575) also concerns itself with recent work on the distribution of species. It turns out to be scale dependant; different processes affect the number of species on different scales. In fact it turns out that competition between individuals affects the frequency of species on a country wide scale.
Then there is the matter of the distribution and frequency of individuals within a species. It turns out that habitat is not important in determining what species live where but competition is. Really … ? Lets have that again. It does not matter just what the environment is like but it matters what the competition is. But should not competition be competition FOR the resources of the environment? No wonder people are surprised.
I just have to believe that in order to understand that differences in the distribution of a species one must understand the scale of the distribution of the components of that species. In other words, like villages scattered among farming landscapes and bands of nomads moving about in the same wilderness populations of wild animals are not randomly mating gene pools. There is a maximum size of such a pool, and it is not very large. They consist of little knots, demes if you will, with mating vastly more common within rather than between groups. It must be that this looks like competition but is not. They are not all poised on the brink of starvation. Wild animals usually look fit but seldom look emaciated. They are just avoiding each other. And any group that outgrows its numerical ceiling pays a penalty, perhaps a fatal penalty, in fertility.
Furthermore competition appears to be important on scales of a few hundred kilometers but not on a scale of one thousand kilometers. It is pointed out in the article that this cutoff is remarkable in its precision. When something in the biology of a population is so precise as to be uncanny, I smell infertility. We have seen how often that has been the case.
So I think what I am offering here, fertility decreases as gene pool size increases (always excluding intense inbreeding), has effects not only upon individuals but upon the entire population.
Again, I feel the urge to rush letters off. But to say I smell the effect is not to say I can see it clearly. I do not know exactly how this would be related to the effects now being published. But with anything like luck they will never need my help. They will work this out as it were from the other side, running down the roots of the things they are observing and ultimately coming to the same conclusion. Besides, I don’t have proper addresses.
At least they are working on it.
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