Compositional Evolution: The Impact of Sex, Symbiosis, And Modularity on the Gradualist Framework of Evolution

by Richard A. Watson

A study of evolutionary processes that involve the combination of systems of semi-independently preadapted genetic material rather than the linear or sequential accumulation of slight modifications; with computational models that illustrate these mechanisms. No biological concept has had greater impact on the way we view ourselves and the world around us than the theory of evolution by natural selection. Darwin's masterful contribution was to provide an algorithmic model (a formal step-by-step procedure) of how adaptation may take place in biological systems. However, the simple process of linear incremental improvement that he described is only one algorithmic possibility, and certain biological phenomena provide the possibility of implementing alternative processes. In Compositional Evolution , Richard Watson uses the tools of computer science and computational biology to show that certain mechanisms of genetic variation (such as sex, gene transfer, and symbiosis) allowing the combination of preadapted genetic material enable an evolutionary process, compositional evolution, that is algorithmically distinct from the Darwinian gradualist framework. After reviewing the gradualist framework of evolution and outlining the analogous principles at work in evolutionary computation, Watson describes the compositional mechanisms of evolutionary biology and provides computational models that illustrate his argument. He uses models such as the genetic algorithm as well as novel models to explore different evolutionary scenarios, comparing evolution based on spontaneous point mutation, sexual recombination, and symbiotic encapsulation. He shows that the models of sex and symbiosis are algorithmically distinct from simpler stochastic optimization methods based on gradual processes. Finally, Watson discusses the impact of compositional evolution on our understanding of natural evolution and, similarly, the utility of evolutionary computation methods for problem solving and design.

324 pages, Hardcover

First published January 1, 2006

About the author

Richard Watson is a recognized and pre-eminent Cartesian scholar and until his retirement was a professor of philosophy at Washington University in St. Louis. He now lives in Missoula, Montana.

Reviews

[Rif A. Saurous · Rating 4 out of 5]

In Darwin's original conception (largely echoed by Dawkins as I understand it), evolution was the accumulation of small gradual changes (because large random changes were far too likely to be bad). Mainstream biology, thanks to the pioneering work of Lynn Margulis (see also Maynard-Smith and Szathmáry on Major Evolutionary Transitions), now accepts that large changes are possible --- for example, the symbiotic acquisition of mitochondria by early eukaryotic cells.

In this 2006 book, Watson (no relation to Watson of Watson & Crick) links evolutionary biology and work in evolutionary computation by building (highly abstracted) computational models of recombination and symbiogenesis. The primary contributions are a family of "modular" problems that are effectively impossible for hill-climbing mutators to solve, and recombination and symbiosis algorithms that solve these problems. In the process, Watson usefully clarifies a number of confusions in evolutionary computation.

This book represents real progress for its time and is genuinely thought provoking. Watson has gone on to do great additional work (in paper, not book form) which I'm now diving into. The book is a little dated, and is a little long in terms of both long-winded phrasings and lots of repetitions, but is still worth reading for those interested in the subject.

[Rohan · Rating 4 out of 5]

Good if not necessarily relevant to real biology. Certainly interesting, though.