Trait Group Selection

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Trait group selection, then, is an interesting combination of selection at the individual organism level and its physical traits and selection on trait groups. Trait groups are groups of organisms united by a certain trait. For an organism to be a member of a trait group, it must be affected, in some way, by all of the other organisms of the group in respect to the unifying trait. We consider the beaver dam example of a trait group (Sterelny and Griffiths 161). There are two types of beavers in our example. There are the freeloaders and the dam-builders. The dam-builder build the dam which benefits all beavers in the area, freeloaders and dam-builders. Freeloaders, as the name suggests, are those beavers who benefit from the dam who didn’t …show more content…

Crickets can only move between lily pads if they are paired up. Each cricket pair, which lasts only the time period that the pair moves between lily pads, is a trait group. For trait group selectionists, selection acts on this trait group. If cricket pairs are trait groups, then trait groups don’t have longer generations than individual organisms. Furthermore, since each cricket pair lasts only the duration of the lily pad journey, there are at least as many cricket pairs as individual crickets. Thus, the threat of within-group selection overpowering between-group selection disappears with respect to trait group selection. At this point, trait group selection is a very attractive view. In summary, trait group selection allows for the existence of genuine altruistic traits and avoids common problems associated with rates of selection typical to most group selection models. However, trait group selection requires selection on at least two levels: the individual organism level and the trait group level. The best competing view to trait group selection would be one that has the same explanatory upshot without admitting to selection on at least two separate levels. Broad individualism is this

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