We introduce the Webworld model\ which links together the ecological modelling of food web structure with the evolutionary modelling of speciation and extinction events[ The model describes dynamics of ecological communities on an evolutionary time!scale[ Species are defined as sets of characteristic features\ and these features are used to determine interaction scores between species[ A simple rule is used to transfer resources from the external environment through the food web to each of the species\ and to determine mean population sizes[ A time step in the model represents a speciation event[ A new species is added with features similar to those of one of the existing species and a new food web structure is then calculated[ The new species may "i# add stably to the web\ "ii# become extinct immediately because it is poorly adapted\ or "iii# cause one or more other species to become extinct due to competition for resources[ We measure various properties of the model webs and compare these with data on real food webs[ These properties include the proportions of basal\ intermediate and top species\ the number of links per species and the number of trophic levels[ We also study the evolutionary dynamics of the model ecosystem by following the fluctuations in the total number of species in the web[ Extinction avalanches occur when novel organisms arise which are significantly better adapted than existing ones[ We discuss these results in relation to the observed extinction events in the fossil record and to the theory of self-organized criticality

Modelling coevolution in multispecies communities

Caldarelli G;
1998-01-01

Abstract

We introduce the Webworld model\ which links together the ecological modelling of food web structure with the evolutionary modelling of speciation and extinction events[ The model describes dynamics of ecological communities on an evolutionary time!scale[ Species are defined as sets of characteristic features\ and these features are used to determine interaction scores between species[ A simple rule is used to transfer resources from the external environment through the food web to each of the species\ and to determine mean population sizes[ A time step in the model represents a speciation event[ A new species is added with features similar to those of one of the existing species and a new food web structure is then calculated[ The new species may "i# add stably to the web\ "ii# become extinct immediately because it is poorly adapted\ or "iii# cause one or more other species to become extinct due to competition for resources[ We measure various properties of the model webs and compare these with data on real food webs[ These properties include the proportions of basal\ intermediate and top species\ the number of links per species and the number of trophic levels[ We also study the evolutionary dynamics of the model ecosystem by following the fluctuations in the total number of species in the web[ Extinction avalanches occur when novel organisms arise which are significantly better adapted than existing ones[ We discuss these results in relation to the observed extinction events in the fossil record and to the theory of self-organized criticality
File in questo prodotto:
File Dimensione Formato  
articleweb.pdf

non disponibili

Licenza: Non specificato
Dimensione 263.6 kB
Formato Adobe PDF
263.6 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11771/4204
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 166
social impact