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Emergent multilevel selection in a simple spatial model of the evolution of altruism

Theories on the evolutionary origins of altruistic behavior have a long history and have become a canonical part of the theory of evolution. Nevertheless, the mechanisms that allow altruism to appear and persist are still incompletely understood. It is well known, however, that the spatial structure...

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Autor principal: Hermsen, Rutger
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9595567/
https://www.ncbi.nlm.nih.gov/pubmed/36282807
http://dx.doi.org/10.1371/journal.pcbi.1010612
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author Hermsen, Rutger
author_facet Hermsen, Rutger
author_sort Hermsen, Rutger
collection PubMed
description Theories on the evolutionary origins of altruistic behavior have a long history and have become a canonical part of the theory of evolution. Nevertheless, the mechanisms that allow altruism to appear and persist are still incompletely understood. It is well known, however, that the spatial structure of populations is an important determinant. In both theoretical and experimental studies, much attention has been devoted to populations that are subdivided into discrete groups. Such studies typically imposed the structure and dynamics of the groups by hand. Here, we instead present a simple individual-based model in which altruistic organisms spontaneously self-organize into spatially separated colonies that themselves reproduce by binary fission and hence behave as Darwinian entities in their own right. Using software to automatically track the rise and fall of colonies, we are able to apply formal theory on multilevel selection and thus quantify the within- and among-group dynamics. This reveals that individual colonies inevitably succumb to defectors in a within-colony “tragedy of the commons”. Even so, altruism persists in the population because more altruistic colonies reproduce more frequently and drive less altruistic ones to extinction. Evidently, the colonies promote the selection of altruism but in turn depend on altruism for their existence; the selection of altruism hence involves a kind of evolutionary bootstrapping. The emergence of the colonies also depends crucially on the length scales of motility, altruism, and competition. This reconfirms the general relevance of these scales for social evolution, but also stresses that their impact can only be understood fully in the light of the emergent eco-evolutionary spatial patterns. The results also suggest that emergent spatial population patterns can function as a starting point for transitions of individuality.
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spelling pubmed-95955672022-10-26 Emergent multilevel selection in a simple spatial model of the evolution of altruism Hermsen, Rutger PLoS Comput Biol Research Article Theories on the evolutionary origins of altruistic behavior have a long history and have become a canonical part of the theory of evolution. Nevertheless, the mechanisms that allow altruism to appear and persist are still incompletely understood. It is well known, however, that the spatial structure of populations is an important determinant. In both theoretical and experimental studies, much attention has been devoted to populations that are subdivided into discrete groups. Such studies typically imposed the structure and dynamics of the groups by hand. Here, we instead present a simple individual-based model in which altruistic organisms spontaneously self-organize into spatially separated colonies that themselves reproduce by binary fission and hence behave as Darwinian entities in their own right. Using software to automatically track the rise and fall of colonies, we are able to apply formal theory on multilevel selection and thus quantify the within- and among-group dynamics. This reveals that individual colonies inevitably succumb to defectors in a within-colony “tragedy of the commons”. Even so, altruism persists in the population because more altruistic colonies reproduce more frequently and drive less altruistic ones to extinction. Evidently, the colonies promote the selection of altruism but in turn depend on altruism for their existence; the selection of altruism hence involves a kind of evolutionary bootstrapping. The emergence of the colonies also depends crucially on the length scales of motility, altruism, and competition. This reconfirms the general relevance of these scales for social evolution, but also stresses that their impact can only be understood fully in the light of the emergent eco-evolutionary spatial patterns. The results also suggest that emergent spatial population patterns can function as a starting point for transitions of individuality. Public Library of Science 2022-10-25 /pmc/articles/PMC9595567/ /pubmed/36282807 http://dx.doi.org/10.1371/journal.pcbi.1010612 Text en © 2022 Rutger Hermsen https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Hermsen, Rutger
Emergent multilevel selection in a simple spatial model of the evolution of altruism
title Emergent multilevel selection in a simple spatial model of the evolution of altruism
title_full Emergent multilevel selection in a simple spatial model of the evolution of altruism
title_fullStr Emergent multilevel selection in a simple spatial model of the evolution of altruism
title_full_unstemmed Emergent multilevel selection in a simple spatial model of the evolution of altruism
title_short Emergent multilevel selection in a simple spatial model of the evolution of altruism
title_sort emergent multilevel selection in a simple spatial model of the evolution of altruism
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9595567/
https://www.ncbi.nlm.nih.gov/pubmed/36282807
http://dx.doi.org/10.1371/journal.pcbi.1010612
work_keys_str_mv AT hermsenrutger emergentmultilevelselectioninasimplespatialmodeloftheevolutionofaltruism