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arXiv · 1403.7865

Path integral calculation for emergence of rapid evolution from demographic stochasticity

Hong-Yan Shih·Nigel Goldenfeld
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Abstract

Genetic variation in a population can sometimes arise so fast as to modify ecosystem dynamics. Such phenomena have been observed in natural predator-prey systems, and characterized in the laboratory as showing unusual phase relationships in population dynamics, including a $\pi$ phase shift between predator and prey (evolutionary cycles) and even undetectable prey oscillations compared to those of the predator (cryptic cycles). Here we present a generic individual-level stochastic model of interacting populations that includes a subpopulation of low nutritional value to the predator. Using a master equation formalism, and by mapping to a coherent state path integral solved by a system-size expansion, we show that evolutionary and cryptic quasicycles can emerge generically from the combination of intrinsic demographic fluctuations and clonal mutations alone, without additional biological mechanisms.

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Hong-Yan Shih, Nigel Goldenfeld. 2014-03-31. Path integral calculation for emergence of rapid evolution from demographic stochasticity. https://doi.org/10.1103/physreve.90.050702

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