EVOLUTION AND ECOLOGY

Erik Rauch, Justin Werfel, Daniel Rosenbloom, Hiroki Sayama, Marcus A. M. de Aguiar, Michel Baranger, Charles Goodnight, Les Kaufman, Yaneer Bar-Yam

A historical dispute in the conceptual underpinnings of evolution is the validity of the gene centered view of evolution. We transcend this debate by formalizing the gene centered view and establishing the limits on its applicability. We show that the gene-centered view is a dynamic version of the well known mean field approximation. It breaks down for trait divergence which corresponds to symmetry breaking in evolving populations.

Using this understanding, we study the role of spontaneous pattern formation in the creation and maintenance of biological diversity. Preliminary analysis and simulations demonstrate that spontaneous pattern formation in the presence of disruptive selection increases the generation and duration of genetic diversity. These patterns interact with boundary and internal barrier structure so as to generate counter-intuitive increases in diversity in patches with high perimeter-to-core ratios. This effect is increasingly pronounced for organisms that exhibit a restricted mating neighborhood.

The approach we use merges methodologies from statistical physics with models of evolutionary processes. The appearance of spontaneous pattern formation in spatially distributed populations is directly analogous to symmetry breaking and coarsening in conventional physics models, e.g. Ising models of magnets. Thus, our approach is an extension of the methods developed in the study of correlations in systems that undergo phase transitions through symmetry breaking.

This research has immediate implications for the design of protected habitats that can maintain or reverse the current dramatic decrease in biodiversity. Moreover, this approach may provide a new theory of both the origins of diversity and the mechanisms of sympatric speciation.

Papers:

E. M. Rauch and Y. Bar-Yam: PNAS 102, pp. 9826-9829, July 12, 2005. abstract PDF file

E. M. Rauch and Y. Bar-Yam: Nature 431, pp. 449-452, Sept. 23, 2004. PDF file

J. K. Werfel and Y. Bar-Yam: The evolution of reproductive restraint through social communication, PNAS 101, pp. 11019-11024, 2004. PDF file

M. A. M. de Aguiar, E. M. Rauch, and Y. Bar-Yam: Invasion and Extinction in the Mean Field Approximation for a Spatial Host-Pathogen Model, Journal of Statistical Physics 114, pp. 1417-1451, 2004. PDF file

M. A. M. de Aguiar, M. Baranger, Y. Bar-Yam, and H. Sayama: Robustness of spontaneous pattern formation in spatially distributed genetic populations, Brazilian Journal of Physics 33, 514, 2003.

H. Sayama, L. Kaufman, M. A. M. de Aguiar, E. Rauch, C. Goodnight, and Y. Bar-Yam: Breakdown of the gene-centered view: What is beyond Neo-Darwinian evolution?, Proceedings of the Fourth International Conference on Complex Systems, Perseus Books / InterJournal, to appear.

E. M. Rauch, M. A. M. de Aguiar, and Y. Bar-Yam, Mean Field Approximation To a Spatial Host-Pathogen Model, Phys. Rev. E 67, 047102, 2003. PDF file

H. Sayama, M. A. M. de Aguiar, Y. Bar-Yam, and M. Baranger, Interplay between Turing pattern formation and domain coarsening in spatially extended population models, FORMA, SciPress, Tokyo, Japan, 2003 (in press). PDF file

H. Sayama, L. Kaufman, and Y. Bar-Yam: Spontaneous pattern formation and genetic diversity in habitats with irregular geographical features, Conservation Biology 17, 893, 2003.

E. M. Rauch, H. Sayama, and Y. Bar-Yam, Dynamics and genealogy of strains in spatially extended host pathogen models, J. Theor. Biol. 221, 655-664 (2003). PDF file

M. A.M. de Aguiar, H. Sayama, E. Rauch, Y. Bar-Yam, and M. Baranger, Stability and Instability of Polymorphic Populations and the Role of Multiple Breeding Seasons in Phase III of Wright's Shifting Balance Theory, Phys. Rev. E 65, 031909 (2002). PDF file

E. Rauch, H. Sayama, and Y. Bar-Yam, Relationship between measures of fitness and time scale in evolution, Phys. Rev. Lett. 88, 228101 (2002). PDF file

H. Sayama, M.A.M. de Aguiar, Y. Bar-Yam and M. Baranger, Spontaneous pattern formation and genetic invasion in locally mating and competing populations, Phys. Rev. E 65, 051919 (2002). PDF file

H. Sayama and Y. Bar-Yam: The gene centered view of evolution and symmetry breaking and pattern formation in spatially distributed evolutionary processes, Nonlinear Dynamics in the Life and Social Sciences, W. Sulis and I. Trofimova, eds., NATO Science Series A/320, pp.360-368, 2001, IOS Press. PDF file

H. Sayama, Self-Replicating Worms That Increase Structural Complexity through Gene Transmission, Artificial Life, M. A. Bedau, J. S. McCaskill, N. H. Packard and S. Rasmussen, eds., pp.21-30, 2000, MIT Press. PDF file PostScript (gzipped)

H. Sayama, L. Kaufman and Y. Bar-Yam: Symmetry breaking and coarsening in spatially distributed evolutionary processes including sexual reproduction and disruptive selection, Physical Review E 62, pp.7065-7069 (2000). PDF file (Also available in other formats at Los Alamos arXiv)

Y. Bar-Yam, Formalizing the gene centered view of evolution, Advances in Complex Systems 2, pp.277-281 (1999). PDF file (Also available in other formats at Los Alamos arXiv) article

H. Sayama, A new structurally dissolvable self-reproducing loop evolving in a simple cellular automata space, Artificial Life 5:4, pp.343-365 (1999). Full text (PDF file)

H. Sayama, L. Kaufman and Y. Bar-Yam, The role of spontaneous pattern formation in the creation and maintenance of biological diversity, InterJournal, Brief Article 417, submitted.

Y. Bar-Yam and H. Sayama, Formalizing the gene centered view of evolution, InterJournal, Brief Article 385, accepted.

H. Sayama, Spontaneous evolution of self-reproducing loops on cellular automata, InterJournal, Brief Article 236, accepted.

Back to NECSI Research page