Wolfram Science Group
Phoenix, AZ USA
Registered: Aug 2003
Review article on NKS and Ecology
The journal Oikos had an article in July 2005 (volume 110, pages 203-207) that I recently ran across, by K. Rohde - an ecologist in Australia - entitled "Cellular Automata and Ecology". It was one of the best short overviews of NKS and open issues in bio I've seen, and made a number of points I had not seen before.
Here is its abstract, first, then a little discussion.
Abstract: "A fascinating and potentially very fertile new approach for solving various scientific problems in mathematics, physics, cosmology, chemistry, biology, psychology and economics, to mention only the most important ones, is that pioneered by Stephan Wolfram. In the following, I give a brief outline of his "NKS" (new kind of science") with emphasis on cellular automata; some of his conclusions concerning evolutionary biology; a comparison with other approaches; and an application of the method to some problems of ecology. The principles of NKS ("new kind of science") developed by Stephen Wolfram are discussed, with emphasis on cellular automata. Wolfram's conclusions concerning optimisation and the evolution of complexity in biological systems are outlined and compared with those from some other recent approaches. NKS is applied to some central problems of ecology, i.e. the possibility of establishing general ecological laws, the existence of vacant niches, the importance of interspecific competition and the causes of latitudinal gradients in species diversity."
(End abstract, begin my comments on the article)
The article is noteworthy first of all for getting right the position NKS takes on the role of natural selection within evolution. The author mentions a number of bits of evidence in support of the NKS position (which in a nutshell is that sampling a space of random programs accounts for most biological complexity, rather than optimizing natural selection doing so), some of them covered in the book or previously mentioned on this forum, some new.
The previously mentioned ones include early appearance of wide variety in the fossil record, populated parameter spaces of biological patterns and forms, wide differences in patterning for closely related species, the general formal weakness of random search optimization and its tendency to find only local extrema - among others. The new ones include ecological evidence cited by the author for the prevalence of empty niches (particularly strong for cases like parasites), the low prevalence of direct competition between species, and perhaps most striking the variation in species diversity with lattitude.
The last means simply the tendency of biological diversity to be highest in the tropics and much lower in the temperate zones. Ambient temperature is known to correlate with mutation rates, and the author speculates that regions of higher temperature are simply generating more random alerations to existing genetic programs, a high portion of which persist. Rather than a niche-pull model of diversity generation, it is an algorithmic randomness-push model, and he argues this fits the observed lattitude variation in diversity neatly and parsimoniously.
The author also spends some time on the implications of NKS for ecological method and the ability to find general laws for ecology, given the likelihood that most ecological systems are computationally irreducible. More than he emphasizes, I would argue this points to explicit computer simulation as a necessary method in ecology. We are only going to see how intricate relations in a given system typically interact if we carry out parallel computations to those the system itself actually performs over its history.
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