The authors declare that they have no competing interests. Accepted Apr This article has been cited by other articles in PMC. Abstract Kin selection and multilevel selection are two major frameworks in evolutionary biology that aim at explaining the evolution of social behaviors.
Image courtesy of Urban Advertisement Want to start a brawl at an evolution conference? Just bring up the concept of group selection: By the s, however, selection at the group level was on the outs. Instead, he claims, selection operates on genes—the individual is the embodiment of the selection of thousands of selfish genes, each trying to perpetuate itself.
In the past few decades, however, group selection has made a quiet comeback among evolutionary theorists. Wilson of Harvard University and David Sloan Wilson no relation of Binghamton University are trying to give group selection full-fledged respectability.
They are rebranding it as multilevel selection theory: And how do you figure the sum of those selections in any real-world circumstance? Pseudomonas fluorescens bacteria quickly suck all the dissolved oxygen out of a liquid habitat, leaving a thin habitable layer near the surface. But some bacteria spontaneously develop a beneficial mutation.
These group-saving individuals secrete a polymer that enables bunches of individuals to form floating mats. As a mat, all the bacteria survive, even though most of them expend no metabolic energy producing the polymer.
But if the freeloaders get greedy and reproduce too many of their kind, the mat sinks and everybody dies, altruists and freeloaders alike. Among these bacteria, then, groups that maintain enough altruists to float outcompete groups with fewer altruists than that minimum number.
The former groups survive, grow and split up into daughter groups. Thus, altruistic individuals can prosper, despite the disadvantage of expending precious resources to produce the polymer. Perhaps the biggest change that group selection brings to evolutionary theory is its implication for so-called kin selection.
What looks like group selection, some theorists argue, can actually be understood as genetic relatedness.
Haldane pithily explained kin selection: Turning that argument on its head, the Wilsons assert that kin selection is a special case of group selection. And that diversity between groups presents clearer choices for group selection. Kinship thus accentuates the importance of selection at the group level as compared with individual selection within the group.
Altruistic groups beat selfish groups.The distinction between kin and group selection is arbitrary Because kin selection theory often encourages emphasis of the interaction structure to the exclusion of the mating structure, a.
In order for kin selection to be important, the related kin have to be in groups that preferentially confer altruistic behaviors on each other. In order for group selection to operate, the members of a group have to be closer kin than they are to other groups. Multi-level Selection Theory explains the evolution of altruism by considering the action of natural selection not on an individual but on a group level.
Consider, for example, an animal population made up of warring tribes. This would entail two levels of selection - between groups and within groups. Within any one tribe, altruistic behaviour would be deselected by the dominance of selfish.
Group selection is a proposed mechanism of evolution in which natural selection acts at the level of the group, instead of at the more conventional level of the individual..
Early authors such as V. C. Wynne-Edwards and Konrad Lorenz argued that the behavior of animals could affect their survival and reproduction as groups, speaking for instance of actions for the good of the species.
However, their evolution is more strongly dictated by artificial selection (crop breeding), which incorporates individual and group selection, making multilevel selection more relevant than kin selection in favouring altruism.
Multilevel selection signiﬁcantly reduced mortality (% K vs. % R) and increased weight ( g/MG K vs. g/MG R) resulting in response an order of magnitude greater with Kin .