Altruism is the opposite of selfishness, it is the selflessness concern for the well being of others. How or why did such behavior evolve? Let’s consider reciprocal altruism, it is the idea of helping someone else at a cost to the individual or organism performing the act. Such behavior most likely evolved because the benefits from helping someone else outweighed the cost, for example, the individual or organism that was helped could have performed an altruistic act towards the individual whom helped him earlier. There are several examples of organism that perform reciprocal altruistic acts such as vampire bats who will shared some of the blood they obtain with another bat that was unsuccessful at finding food. Another example can be found in meercats, they perform altruistic acts by taking care of unrelated young meercats while the parents and the rest of the pack goes out to look for food or by staying on the look-out for predators while the rest look for food. With the previous examples in mind, let us change gears and think about the prisoner’s dilemma.
The prisoner’s dilemma deals with the interaction between two individuals and whether they choose to cooperate or defect. If both individuals cooperate, they both obtain a reasonable benefit or payoff. If one of them cooperates and the other defects, one of them gets a better payoff than the previous mutualistic act but the other gets a very low payoff or benefit. If both individuals defect, they both received a fairly bad payoff. Can it be solved? As Dawkins explained on chapter 12 of the selfish gene, the best move is always to defect. If two rational individuals are involved in such interaction, it is more logical to defect (due to lack of trust on the other individual) and received the less harsher payoff or punishment, even when they both could get a reasonable payoff if only both would cooperate. There lies the idea of the prisoner’s dilemma.
Monday, October 26, 2009
Sunday, October 25, 2009
What's in it for them? Queen VS workers
In the Selfish Gene, Dawkins introduces the idea of social insect individuals being divided into two main classes: the bearers and the carers. The bearers are those who reproduce and the carers/workers are those who perform work and are usually infertile. Both types carry out their jobs efficiently because they do not have to cope with each other.
If the workers are unable to reproduce, why aid the queen? What’s in it for them? Dawkins states that the workers “farm” the reproductive individuals, meaning that the workers manipulate the queen to propagate the worker’s genes. The conflict in this system lies in the sex ratio. The queen favors a 1:1 females to males sex ratio whereas the workers favor a 3:1 females to males ratio.
It makes sense that the queen benefits by investing equally in both sexes, but why do workers favor females over males? A simplified answers is that males contain just a single set of chromosomes (all passed on from the mother) whereas the females contain a double set of chromosomes (obtained from the mother and father). Among the females, full sisters are identical twins as far as their parental genes, thus females benefit by “farming” their own mother into a “sister-making” machine.
Is there a winner? Trivers and Hare found that among 20 species of ants, the workers bias the sex ratio in favor of females (The Selfish Gene, pp. 176-178). However some species of ants, after defeating another colony of ants, take the unhatched ants who become slaves. These slaves, not knowing that their not related to the queen, performed as workers yet do not affect the queen’s preferences.
If the workers are unable to reproduce, why aid the queen? What’s in it for them? Dawkins states that the workers “farm” the reproductive individuals, meaning that the workers manipulate the queen to propagate the worker’s genes. The conflict in this system lies in the sex ratio. The queen favors a 1:1 females to males sex ratio whereas the workers favor a 3:1 females to males ratio.
It makes sense that the queen benefits by investing equally in both sexes, but why do workers favor females over males? A simplified answers is that males contain just a single set of chromosomes (all passed on from the mother) whereas the females contain a double set of chromosomes (obtained from the mother and father). Among the females, full sisters are identical twins as far as their parental genes, thus females benefit by “farming” their own mother into a “sister-making” machine.
Is there a winner? Trivers and Hare found that among 20 species of ants, the workers bias the sex ratio in favor of females (The Selfish Gene, pp. 176-178). However some species of ants, after defeating another colony of ants, take the unhatched ants who become slaves. These slaves, not knowing that their not related to the queen, performed as workers yet do not affect the queen’s preferences.
Monday, October 12, 2009
Upgrating Generations: Natural vs. Sexual Selection
“Man selects only for his own good; Nature only for that of the being which she tends.” – Charles Darwin
Darwin explained the principle by which slight variations of traits, if useful, were preserved. Such preservation of favorable variations, and the rejection of those variations which were not beneficial, is what he referred to as Natural Selection. Moreover, Darwin explains that natural selection is dependent on a “state of nature” which enables the modifications of “organic beings” through the accumulation of “profitable” variations. Furthermore, Darwin argues that natural selection cannot modify the structure of a species without providing a certain advantage, hitting towards the role of sexual selection. Darwin defined sexual selection not as a struggle for existence but as the effects of the "struggle between the males for possession of the females,” the result not being death to the unsuccessful but lower production of progeny.
Natural selection is dependent on interactions with the environment. Dawkins argued that the gene’s survival is dependent on their interaction with the environment. Moreover, Dawkins argued that the environment also consisted of genes, which cooperate and compete with each other. Those who are better at cooperating and better in competing will persist. Sexual production is mainly shifted towards the greater production of quality progeny. In the “selfish” view, females look for the most fit male to mate with and better enhance her genes while passing them onto future generations.
Darwin explained the principle by which slight variations of traits, if useful, were preserved. Such preservation of favorable variations, and the rejection of those variations which were not beneficial, is what he referred to as Natural Selection. Moreover, Darwin explains that natural selection is dependent on a “state of nature” which enables the modifications of “organic beings” through the accumulation of “profitable” variations. Furthermore, Darwin argues that natural selection cannot modify the structure of a species without providing a certain advantage, hitting towards the role of sexual selection. Darwin defined sexual selection not as a struggle for existence but as the effects of the "struggle between the males for possession of the females,” the result not being death to the unsuccessful but lower production of progeny.
Natural selection is dependent on interactions with the environment. Dawkins argued that the gene’s survival is dependent on their interaction with the environment. Moreover, Dawkins argued that the environment also consisted of genes, which cooperate and compete with each other. Those who are better at cooperating and better in competing will persist. Sexual production is mainly shifted towards the greater production of quality progeny. In the “selfish” view, females look for the most fit male to mate with and better enhance her genes while passing them onto future generations.
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