Monday, April 5, 2010
Kin Selection
When introducing natural selection in the chapter "The Enging of Evolution," Jerry Coyne stresses the coordination of "randomness" and "lawfulness" in the process of natural selection (or "the non-random survival of random variants"). At first glance, the randomness seems insignificant; however, in reality, it is absolutely necessary for any type of purposeful change in the population to take place. The importance of randomness is highlighted in increasing the fitness of the species rather than the individual. Relate this concept to kin selection. Does evolution through kin selection work against this process by limiting variation?
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I believe that evolution would be limited by kin selection only if these organisms can survive independently and do not rely on a community/population to survive. Kin selection is the altruistic behavior that a species has with its relatives. This behavior may lead to decrease in variation, but I believe this is because the idea of kin selection effectively maintains a species' population, which is the primary reason for evolution: to be efficient in both survival and reproduction. As Jerry Coyne had said early in the book, natural selection does not eliminate species that are not as "fit" as other species if these "less fit" species can still survive under the conditions they are living in. This altruistic behavior ensures the survival of the general population of organisms at the cost of one organism rather than the cost of an entire population.
ReplyDeleteI agree with Andrew in his point that kin selection may decrease genetic variation, but I do feel that there is more rational to altruistic behavior that ensuring the survival of the population. Remember, since organisms "differs genetically from one another" (11), the goal of every organism is "to survive and reproduce in its environment" to keep the organism's gene pool alive.
ReplyDeleteWhat I mean is that an organism performs kin selection with the rational that increasing the fitness of a reproducing relative in turn helps spread the original organisms genes. In other words, if I was an organism (which I am) that could not reproduce anymore (which is not me yet), I would help my reproductively capable relative survive even if I die so that my gene pool will continue to exist when my relative reproduces. I may be willing to die for kin, but I am much more reluctant to die for a stranger which has different genes from me. I am helping kin because they will then be able to keep alive my genes not because I am afraid the entire species will become extinct.
Thereby, I disagree with Andrew's point that kin selection "ensures the survival of the general population," and I believe that kin selection is for the purpose of maintaining a specific organisms gene pool.
This also connects to evolution and natural selection because an organism could only perform kin selection if it has the "good genes" best suited for an environment. If an organism was struggling to survive by itself, how could it help kin survive?
I don’t think that kin selection limits variation of evolution. I agree with Frank in that kin selection ensures the survival of that particular organism’s genes, as opposed to the survival of the population. If anything, kin selection would add to variation by keeping certain strains alive where they might otherwise die out.
ReplyDeleteExemplifying Interdependence in Nature, certain organisms may be more “geared” for kin selection than others, for example meerkats or wolves – social animals that have more to gain by helping other members of their society than not. Like in the packet we received near the beginning of the year explaining the different roles of certain meerkats, kin-promoting and altruistic behaviors can benefit the entire colony. When the goal of every organism is “to survive and reproduce in its environment,” as Frank noted, this is not always realistic, for example, when the organism itself is struggling for survival. If an organism is unable to take care of itself, and ends up dying, then those genes were most likely an impractical combination given the environment, and should not be passed on.
(Meerkat Packet)