Sympatric Speciation Through Assortative Mating in a Long-Range Cellular Automaton

  • Franco Bagnoli
  • Carlo Guardiani
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3305)


A probabilistic cellular automaton is developed to study the combined effect of competition and assortativity on the speciation process in the absence of geographical barriers. The model is studied in the case of long-range coupling. A simulated annealing technique was used in order to find the stationary distribution in reasonably short simulation times. Two components of fitness are considered: a static one that describes adaptation to environmental factors not related to the population itself, and a dynamic one that accounts for interactions between organisms such as competition. The simulations show that both in the case of flat and steep static fitness landscape, competition and assortativity do exert a synergistic effect on speciation. We also show that competition acts as a stabilizing force preventing the random sampling effects to drive one of the newborn populations to extinction. Finally, the variance of the frequency distribution is plotted as a function of competition and assortativity, obtaining a surface that shows a sharp transition from a very low (single species state) to a very high (multiple species state) level, therefore featuring as a phase transition diagram. Examination of the contour plots of the phase diagram graphycally highlights the synergetic effect.


Contour Plot Cellular Automaton Assortative Mating Sympatric Speciation Phenotypic Distance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Schlieven, U., Tautz, D., Pääbo, S.: Sympatric speciation suggested by monophyly of crater lake cichlids. Nature 368, 629–632 (1994)CrossRefGoogle Scholar
  2. 2.
    Kondrashov, A., Kondrashov, F.: Interactions amon quantitative quantitative traits in the course of sympatric speciation. Nature 400, 351–354 (1999)CrossRefGoogle Scholar
  3. 3.
    Dieckmann, U., Doebeli, M.: Evolutionary branching and sympatric speciation caused by different types of ecological interactions (2000); IIASA Interim Report IR-00-040 (July 2000)Google Scholar
  4. 4.
    Dieckmann, U., Doebeli, M.: On the origin of species by sympatric speciation. Nature 400, 354–357 (1999)CrossRefGoogle Scholar
  5. 5.
    Falconer, D., Mackay, T.: Introduction to Quantitative Genetics, 4th edn. Addison-Wesley Publishing Company, Reading (1996)Google Scholar
  6. 6.
    Doebeli, M.: A quantitative genetic competition model for sympatric speciation. Journal of evolutionary biology 9, 893–909 (1996)CrossRefGoogle Scholar
  7. 7.
    Fisher, R.: The genetical theory of natural selection. Clarendon Press, Oxford (1930)zbMATHGoogle Scholar
  8. 8.
    Holland, J.: Adaptation in natural and artificial systems. MIT Press, Cambridge (1975)Google Scholar
  9. 9.
    Price, G.: Fisher’s fundamental theorem made clear. Annals of human genetics 36, 129–140 (1972)CrossRefMathSciNetGoogle Scholar
  10. 10.
    Ewens, W.: An interpratation and proof of the fundamental theorem of natural selection. Theoretical population biology 36, 167–180 (1989)zbMATHCrossRefMathSciNetGoogle Scholar
  11. 11.
    Bagnoli, F., Bezzi, M.: Speciation as pattern formation by competition in a smooth fitness landscape. Physical Review Letters 79, 3302 (1997)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Franco Bagnoli
    • 1
    • 2
    • 3
  • Carlo Guardiani
    • 3
  1. 1.Dipartimento di EnergeticaUniversità di FirenzeFirenzeItaly
  2. 2.INFN, sez.Firenze
  3. 3.Centro Interdipartimentale per lo Studio delle Dinamiche ComplesseUniversità di FirenzeSesto FiorentinoItaly

Personalised recommendations