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Results for “social evolution”

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At least 73 records · Page 4Linked to original sources
PubMed2000

A skew model for the evolution of sociality via manipulation: why it is better to be feared than loved.

Concession-based reproductive skew models predict that social groups can form via persuasion, whereby dominant individuals forfeit some reproduction to subordinates as an incentive to stay and help. We have developed an alternative skew model based on manipulation, whereby dominant individuals coerce subordinates into staying and helping by imposing costs on their independent reproductive prospects. Stable groups can evolve under a much wider range of genetic and ecological conditions under this manipulation model than under concession models. We describe evidence that various forms of pre-emptive and ongoing manipulation occur in nature and we discuss the implications of the model for the development of a general theory of social evolution.

Animals↗
PubMed2001

The evolution of social behavior in microorganisms.

Recent studies of microorganisms have revealed diverse complex social behaviors, including cooperation in foraging, building, reproducing, dispersing and communicating. These microorganisms should provide novel, tractable systems for the analysis of social evolution. The application of evolutionary and ecological theory to understanding their behavior will aid in developing better means to control the many pathogenic bacteria that use social interactions to affect humans.

Journal Article↗
PubMed1999

The roles of phylogeny and sociality in the evolution of social play in muroid rodents.

A composite index incorporating the frequency and structure (target, type of defence, etc.) of play fighting was used to compare the complexity of such play in 13 species of muroid rodents whose behaviour has been previously described. A phylogenetic comparison of the distribution of the complexity of play fighting revealed that relatedness did not predict complexity. The most likely pattern for the ancestral rodent was moderate levels of complexity, from which increases or decreases in complexity then appeared to have evolved independently, at the level of subfamily and genus. Given that phylogeny did not predict the distribution of the pattern of play fighting, an alternative hypothesis was tested. That is, that instead, the distribution was produced by species differences in sociality, as reflected by the degrees of male-female association amongst adults. The analysis revealed that play complexity was unrelated to species differences in sociality, with both highly social and relatively asocial species being equally likely to have high or low levels of play complexity. The implications of these results for the evolution of mammalian play are considered. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2005

Neocortex evolution in primates: the "social brain" is for females.

According to the social intelligence hypothesis, relative neocortex size should be directly related to the degree of social complexity. This hypothesis has found support in a number of comparative studies of group size. The relationship between neocortex and sociality is thought to exist either because relative neocortex size limits group size or because a larger group size selects for a larger neocortex. However, research on primate social evolution has indicated that male and female group sizes evolve in relation to different demands. While females mostly group according to conditions set by the environment, males instead simply go where the females are. Thus, any hypothesis relating to primate social evolution has to analyse its relationship with male and female group sizes separately. Since sex-specific neocortex sizes in primates are unavailable in sufficient quantity, I here instead present results from phylogenetic comparative analyses of unsexed relative neocortex sizes and female and male group sizes. These analyses show that while relative neocortex size is positively correlated with female group size, it is negatively, or not at all correlated with male group size. This indicates that the social intelligence hypothesis only applies to female sociality.

Animals↗
PubMed1994

Ecosystem theory of evolution and social ethics.

Ecosystem evolution is driven by general laws for open systems aiming at immortality (first genetical then also cultural) of its components. Evolutionary impulses spread downward from ecosystem disturbances to population strategies to genome structures (opposite to the upward causation of traditional theory). Environmental cycles work as winding engine pushing evolution a step further at each round. Natural selection is being slackened with time while memory elaborates to conscious level. General trend is from unsustained growth to stability, individuation, increased diversity, standing biomass to productivity to dead mass ratios. Progressive evolution is interrupted by biospheric crises, or backward developments. Human activities contribute to the latter while for sustainable existence it will be necessary to switch from the crisis to the progress scheme. Human morals are grounded in million years of pre-human and pre-historic human evolution. However to be taught by nature means to comply with its progressive rather than backward tendencies. Human history as a continuation of the animal history is a perpetual struggle against natural selections.

Biological Evolution↗
PubMed2003

'Gatherings' of social grooming among wild chimpanzees: implications for evolution of sociality.

Chimpanzees (Pan troglodytes) often groom in gatherings that cannot simply be divided into unilateral dyadic grooming interactions. This feature of grooming is studied at two different levels: grooming cliques and grooming clusters. Grooming cliques are defined as directly connected configurations of grooming interactions at any given moment, and when any member of a clique successively grooms any member of another clique within 5min and within a distance of 3m, all the members of both cliques are defined as being in the same grooming cluster. Twenty-seven types of cliques are observed, with the largest one consisting of seven individuals. Mutual and/or polyadic cliques account for more than 25% of all cliques. The size of grooming clusters varies from two to 23 individuals, and almost 70% of the grooming time is spent in polyadic clusters. Although adult males groom the longest in relatively smaller clusters (size=2-4), adult females groomed the longest in clusters of five or more individuals. A review of the literature implies that mutual and polyadic cliques occur less often in other primate species than in chimpanzees. The importance of overlapping interactions for these kinds of gatherings and its possible significance in the evolution of sociality is discussed in this article.

Age Factors↗