Kin Selection Theory, Essay Example

Kin selection theory is based on the concept, as put forward by W.D Hamilton ( theory of altruism) that people are more willing to help relatives than others because it increases the odds of gene transmission to future generations. Hence ” altruism towards close relatives occurs in order to ensure the continuation of shared genes. The more closely the individuals are related, the more likely people are to help.” (Wagner, 2009)

The immediate concern with “Kin Theory” is it requires the human or animal (species) to be able to acquire and understand the degree of “relatedness” to another.  This is less of an issue in a closely bonded family group but more problematic where the social grouping cannot be readily distinguished.  One example is that of a bee hive and the colony workers relationship to the Queen.  The colony bees will work with each other in the defence of the Queen in order to protect future generations. The counter argument to this being ” However the use of eusocial insects is problematic since there is no possibility of an unrelated insect ever being present in the colony. Therefore there is no way to determine whether the behavior is due to simple proximity, kin relatedness, or response to the social group itself. In effect, there is no way to test kin selection theory in this case since every insect is, by definition, kin. ” (Adam, 2009)

A good example of altruistic behaviour is found in the ant species. Evolutionary speaking ants are ideal for supporting the Kin theory, consider .. ” Suppose that a rare gene for altruism is present in an individual. Let r denote likelihood that it is also in another individual, given as a probability between 0 and 1. This can be deduced from Mendelian rules. If the new mutation is in a parent, there is a 1/2 chance it will be in its offspring; and there is likewise a 1/2 chance that a gene in an individual is also in its brother or sister”  (Mark, 1985)

Professor  Edward O Wilson at Harvard University, a noted biologist, has renounced the validity of the Kin theory in insects, particularly ants, bees and wasps.  Wilson stated that these creatures are not naturally altruistic by nature and do not necessarily need to spread their genes in this way. Wilson and other scientists assert that this is really just a question of evolution and the insects have simply evolved in this way. ” altruistic behavior has simply evolved because those colonies in which individual insects made more personal sacrifices were more likely to survive and therefore this trait has been naturally selected.”  (Nic Fleming, 2008)

There are two relatively recent theories on Kin Selection. These are:

1. The Altruistic Gene Theory and;
2. The Gene quality Theory

Altruistic Gene Theory

A single gene inducement persuading individuals to select kin for altruism. The theory being that it increases the chances of other individuals to carry the related gene. ” The gene is

disadvantageous at first, but becomes advantageous if it spreads to all members of a population, all of whom then receive more benefit from each other than their altruism costs.” (Philip J. Darlington, 1981).

Gene Quality Theory

Here kin share the same genes in proportion to their kinship. The objective being to increase the quantity of your own genes in the next generation. ” T his is selectively advantageous if the cost to the altruist in loss of offspring is less than the gain in genes, some or all of the altruist’s own offspring being traded off for more-than-equivalent quantities of genes transmitted by kin (this being the essential dogma of the theory); and that for this reason (with no other return to the altruists) genetically determined behaviours by which individuals select kin to be the beneficiaries of altruism have evolved by selection. (Philip J. Darlington, 1981)

The work conducted by Rahman and Hull on the Kin selection theory on homosexual adults has been less supportive of the theory.  This experiment was carried out in England in 2001 and examined how sexual behaviour traits were carried over ” The current investigation, following Bobrow and Bailey (2001), aimed to test the kin selection theory of homosexuality in human males using a survey design. A total of 60 heterosexual and 60 homosexual men from England completed items measuring psychological and behavioral indices of “special design” as predicted by adaptation due to kin selection. There were no significant differences between heterosexual and homosexual men in general familial affinity, generous feelings (willingness to provide financial and emotional resources), and benevolent tendencies (such as willingness to baby-sit). These remained non-significant after co-varying for level of personal income (higher among homosexual men), psychological gender, and interest in children. Overall, little support was found for the kin selection theory in a community sample ”  (Q. Rahman, 2005)

Works Cited

Adam, G. (2009, June 12). Retrieved 10 18, 2009, from Scientific Blogging: http://www.scientificblogging.com/gerhard_adam/problem_kin_selection_theory

Mark, R. (1985). The theory of evolution. In R. Mark, The theory of evolution. Toronto: Blackwell Publishing.

Nic Fleming, S. C. (2008). Scientist renounces insect ‘kin selection’ theory. Daily Telegraph (UK) , 1.

Philip J. Darlington, J. (1981). Genes, individuals, and kin selection. Proc. Nati Acad. Sci. USA , 4440-4443.

Rahman, M. S. (2005). An empirical test of the kin selection hypothesis for male homosexuality . Archives of Sexual Behavior, Vol. 34, No. 4., 461-467.

Wagner, K. v. (2009). Psychology. Retrieved 10 18, 2010, from About.com: http://psychology.about.com/od/kindex/g/kin_selection.htm