[[Challenging environments are needed for mutualistic relationships]] Compare to societies, that are made up of individuals of only one species. - symbiosis - mutualism - Pachepsky, E., Taylor, T., and Jones, S. (2002). Mutualism promotes diversity and stability in a simple artificial ecosystem. _Artif. Life_ 8, 5–24. doi:10.1162/106454602753694747 - parasitism An ecological simulation differs from a genetic algorithm in that there is no continuous objective function, only living or not, or reproducing or not. This means pseudo-gradient techniques like REINFORCE, CMA-ES or Differential Evolution are not easily applied. [[An ecology is non-stationary]]. ## Alife references: - [ ] Watson, R., Reil, T., and Pollack, J. B. (2000). “Mutualism, parasitism, and evolutionary adaptation,” in _Artificial Life VII: Proceedings of the Seventh International Conference on Artificial Life_, eds M. Bedau, J. McCaskill, N. Packard, and S. Rasmussen (Cambridge, MA: MIT Press), 170–178. - [ ] Froese, T., Ikegami, T., and Virgo, N. (2012a). “The behavior-based hypercycle: from parasitic reaction to symbiotic behavior,” in _Artificial Life 13: Proceedings of the Thirteenth International Conference on the Simulation and Synthesis of Living Systems_, eds C. Adami, D. M. Bryson, C. Ofria, and R. T. Pennock (Cambridge, MA: MIT Press), 457–464. - [ ] Pattern-Oriented Modeling of Agent-Based Complex Systems: Lessons from Ecology, Grimm 2005, Science.