Inclusive Fitness

In evolutionary biology and evolutionary psychology, the inclusive fitness of an organism is the sum of its classical fitness (how many of its own offspring it produces and supports) and the number of equivalents of its own offspring it can add to the population by supporting others. Advocates of inclusive fitness theory say that an organism can improve its overall genetic success by cooperative social behavior.

From the gene's point of view, evolutionary success ultimately depends on leaving behind the maximum number of copies of itself in the population. Until 1964, it was generally believed that genes only achieved this by causing the individual to leave the maximum number of viable offspring. However, in 1964 W. D. Hamilton proved mathematically that, because close relatives of an organism share some identical genes, a gene can also increase its evolutionary success by promoting the reproduction and survival of these related or otherwise similar individuals.

Belding's ground squirrel provides an example. The ground squirrel gives an alarm call to warn its local group of the presence of a predator. By emitting the alarm, it gives its own location away, putting itself in more danger. In the process, however, the squirrel protects its relatives within the local group (along with the rest of the group). Therefore, if protecting the other squirrels in the immediate area will lead to the passing on of more of the squirrel’s own genes than the squirrel could leave by reproducing on its own, then natural selection will favor giving the alarm call, provided that a sufficient fraction of the shared genes include the gene(s) predisposing to the alarm call. Further study has shown that the self-reported likelihood of risking one's life to save other's life is directly a function of the degree of genetic relatedness to the helper (Burnstein et al., 1994)

Synalpheus regalis, a eusocial shrimp, also is an example of an organism that seeks to increase its inclusive fitness. The larger defenders protect the young juveniles in the colony from outsiders. By ensuring the young's survival, the genes will continue to be passed onto future generations.

Inclusive fitness is more generalized than strict kin selection, which requires that the shared genes are identical by descent. Inclusive fitness is not limited to cases where kin are involved.

Read more about Inclusive Fitness:  Hamilton's Rule, Inclusive Fitness and Altruism, Green-Beard Effects, Inclusive Fitness and Parental Care

Other articles related to "inclusive fitness, fitness, inclusive":

Sex Allocation - Modern Research
... Fishers (1930) theory of equal investment with Hamilton’s (1964) inclusive fitness theory, to show how the ES sex allocation differed from the point of view of the queen and ... Second, they showed how parent-offspring conflict and inclusive fitness (kin selection) theory could generate predictions that could be tested with empirical data ... still provides some of the clearest support for inclusive fitness theory ...
Eusociality - Theories of Social Evolution
... kin selection or inclusive fitness) had to wait for the discovery of the mechanisms for genetic inheritance ... According to inclusive fitness theory, eusociality may be easier for species like ants to evolve, due to their haplodiploidy, which facilitates the operation of ... This unusual situation where females may have greater fitness when they help rear siblings rather than producing offspring is often invoked to explain the multiple ...
Fictive Kinship - Use in Sociobiology
... This coefficient of relationship is an important component of the theory of inclusive fitness, a treatment of the evolutionary selective pressures on the ... Confusingly, inclusive fitness theory is more popularly known through its narrower form, kin selection theory, whose name clearly resonates with former conceptions of 'kinship' in anthropology ... Whilst inclusive fitness theory thus describes one of the necessary conditions for the evolutionary emergence of social behaviors, the details of the proximate conditions mediating ...
Evolutionary Psychologists - Theoretical Foundations
... Hamilton proposed inclusive fitness theory, emphasizing a "gene's-eye" view of evolution ... Inclusive fitness theory resolved the issue of how "altruism" evolved ... are likely to be, and thus how much they might improve the parents' inclusive fitness ...
Inclusive Fitness and Parental Care
... nurtured (collateral versus descendant relatives) and the kind of fitnesses used (inclusive versus personal) in our parsing of nature are orthogonal concepts ... could be considered a dimunition of the offspring's expected fitness ... in the parents' fecundity, and therefore a dimunition of the parent's fitness ...

Famous quotes containing the words fitness and/or inclusive:

    Critics generally come to be critics not by reason of their fitness for this, but of their unfitness for anything else. Books should be tried by a judge and jury as though they were a crime, and counsel should be heard on both sides.
    Samuel Butler (1835–1902)

    We are rarely able to interact only with folks like ourselves, who think as we do. No matter how much some of us deny this reality and long for the safety and familiarity of sameness, inclusive ways of knowing and living offer us the only true way to emancipate ourselves from the divisions that limit our minds and imaginations.
    bell hooks (b. 1955)