Evolutionary Dynamics of a Food Web with Recursive Branching and Extinction

Hiroshi Ito1 and Takashi Ikegami2

Department of General Systems Sciences, The Graduate School of Arts and Sciences,
University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 Japan
1itoh9@dolphin.c.u-tokyo.ac.jp
2ikeg@sacral.c.u-tokyo.ac.jp

Abstract:

  A dynamic systems approach to evolutionary branching and its development in an artificial food web is presented. Predator-prey  interaction among trophic species with two traits generates a variety of evolutionary branching patterns, depending on interaction strengths and mutation rates. Studying branching patterns in a phenotypic space reveals three branching patterns: prey-bifurcation, predator-bifurcation, and net-bifurcation. In particular, a complex food web network emerges through net-bifurcation. A relationship between biomass  and the number of species is analysed by changing the interaction strength. We report that the branching and extinction rates of trophic species reaches a maximum when the number of species, but not the entire biomass, reaches a maximum.



Russell Standish
2002-11-13