Short Communication "Extended Fitness" hypothesis: a link between individual and group selection

Abstract

ABSTRACT.What are the targets of natural selection remains a controversial issue in Biology. Here I propose the "Extended Fitness" hypothesis, in which extended phenotypes emerge as a link between individual and group selection. The basic premise of the extended fitness hypothesis is that extended phenotypes can be used by members of the same group since they are adapted to use them. Thus, extended phenotypes can also contribute to the fitness of members of the same species. Group selection emerges as a natural consequence of the shared use of extended phenotypes, which allow the evolutionary forces acting on individuals to become effective at the group level. The extended fitness hypothesis is supported by several observations found in nature. The hypothesis presented here provides a theoretical framework for the design of both modeling and experimental approaches to studying the role of extended phenotypes in group selection.

The Shared Use of Extended Phenotypes Increases the Fitness of Simulated Populations

“…Extended phenotypes have received significant interest since the original concept emerged in the early 80's (Dawkins, 1982), especially their indirect effects in other individuals or environments (Dawkins, 2004;Bailey, 2012;de Souza, 2013;Blamires et al, 2018;Fisher et al, 2019). Research in the field has been limited by the paucity of empirical models in which extended phenotypes can be manipulated and different evolutionary models be compared.…”

“…Extended phenotypes are described in all taxonomic kingdoms, from viruses (Hoover et al, 2011) to humans (Dixson, 2019). Although the widespread existence of extended phenotypes is clearly established in contemporaneous evolutionary biology (reviewed in Bailey, 2012), the degree and intensity of its effects are still controversial (Hunter, 2009;Bailey, 2012 Besides the obvious effect of the extended phenotypes in the fitness of the organism who generated it, many authors have discussed their indirect genetic effects (Laland, 2004;Wang et al, 2008;de Souza, 2013;Fisher et al, 2019). One type of indirect genetic effect is through social interactions mediated by extended phenotypes (Wang et al, 2008).…”

“…Extended phenotypes could also affect other parties' fitness through niche construction, as discussed by Laland (2004). A few years ago, the extended fitness hypothesis (EFH) had been proposed, which states that extended phenotypes serve as a link between individual and group selection (de Souza, 2013). Suppose the following scenario: a spider web is abandoned by the individual who built it.…”