Tangled Nature: A Model of Evolutionary Ecology

Abstract

We discuss a simple model of co-evolution. In order to emphasise the effect of interaction between individuals the entire population is subjected to the same physical environment. Species are emergent structures and extinction, origination and diversity are entirely a consequence of co-evolutionary interaction between individuals. For comparison we consider both asexual and sexually reproducing populations. We also study competition between asexual and sexual reproduction in a mixed population. In either case the system evolves through periods of hectic reorganisation separated by periods of coherent stable coexistence.

Network properties, species abundance and evolution in a model of evolutionary ecology

“…Their initial location in genotype space does not affect the dynamics. A two-phase switching dynamic is seen consisting of long periods of relatively stable configurations (quasi-Evolutionary Stable Strategies or q-ESSs) interrupted by brief spells of reorganization of occupancy which are terminated when a new q-ESS is found, as discussed in Christensen et al (2002).…”

Flicker Noise in a Model of Coevolving Biological Populations

“…Elements M IJ and M JI both positive represent symbiosis or mutualism, M IJ and M JI both negative represent competition, while M IJ and M JI of opposite signs represent predator-prey relationships. To concentrate on the effects of interspecies interactions, we follow [3,4] in taking M II = 0. As in [4], the offdiagonal elements of M IJ are randomly and uniformly distributed on [−1, 1].…”

“…However, in reality both mutations and natural selection act on individual organisms, and it is desirable to develop and study models in which this is the case. One such model was recently introduced by Hall, Christensen, and coworkers [3,4]. To enable very long Monte Carlo (MC) simulations of the evolutionary behavior, we have developed a simplified version of this model, for which we here present preliminary results.…”

<title>Fluctuations in models of biological macroevolution (Invited Paper)</title>

“…As a result, in recent years several new models have been proposed that are designed to span the disparate ecological and evolutionary timescales. These models include the Webworld model, 6,7,8 the Tangled-nature model, 9,10 and simplified versions of the latter. 11,12,13 In this paper I discuss and compare some of the properties of fluctuations in two simplified coevolution models: the model introduced in Ref.…”