Evolution and the levels of selection

The held works cite Okasha as a framework for evolutionary transitions in individuality and levels of selection. Watson et al. use it for the type-1/type-2 group selection distinction, for the need to separate selection at a new level from lower-level selection, and for the point that collective fitness can be a non-linear function of particle phenotypes even when it is a linear sum of particle fitnesses. They also cite it on suppressing within-group fitness differences. Krakauer et al. link it to long-lived aggregates becoming a target of selection.

Okasha (2006) points to the resolution. Specifically, even if collective fitness is a linear sum of particle fitnesses, collective fitness can nonetheless be a non-linear function of particle phenotypes.

Watson RA, Mills R, Buckley CL, Kouvaris K…, 2016 · Evolutionary Connectionism: Algorithmic Principles Underlying the… · open at passage 86

In order to identify natural selection at a new level of organisation we want to distinguish it from changes that are driven by natural selection at the existing (lower) level of organisation (Okasha 2006).

Watson RA, Mills R, Buckley CL, Kouvaris K…, 2016 · Evolutionary Connectionism: Algorithmic Principles Underlying the… · open at passage 84

This depends on whether we are modelling a type-1 or type-2 group selection process (Okasha 2006; Wilson 1989).

Watson RA, Mills R, Buckley CL, Kouvaris K…, 2016 · Evolutionary Connectionism: Algorithmic Principles Underlying the… · open at passage 94

It is fair to assume that long-lived aggregates could develop the capacity to replicate and become a significant target for selection and hence a bona fide level at which selection operates

Krakauer D, Bertschinger N, Olbrich E, Flack JC…, 2020 · The information theory of individuality · open at passage 73