Question

There are two theories to explain how altruistic behavior evolves: reciprocity and kin selection. A. What is altruistic behavior? Briefly explain why it is difficult to explain the evolution of altruistic behavior in 1-2 sentences. B. You observe a species of birds that appears to engage in altruistic behavior, and you are trying to decide if the behavior can be explained through either reciprocity or kin selection. You closely observe the animals, studying the behavior, and perform genetic analysis to determine the familial relationships between them. Briefly describe what results or observations would support each hypothesis (reciprocity or kin selection) in 2-3 sentences each.

Answer 1

An organism is pronounced to behave altruistically when the behaviour of them benefits another organisms, at a cost to themself. The costs as well as benefits are determined in terms of reproductive fitness (expected offspring number). So an organism behaving altruistically, decreases the offspring number it is probable to produce itself, but increases the fitness of other organisms. In many species of bird, a breeding pair get help in lifting its offspring from another ‘helper’ birds, that guard the nest from predators and also help to augment the learner. Alarm call given by vervet monkeys to alert fellow monkeys of the predators presence, despite of doing so they draw attention to themselves, raising the chance of being attacked of themselves. In colonies of social insect (wasps, termites, bees and ants), whole live devotion of sterile workers in caring of queen, building and guiding the nest, search madly for food, and giving attention to the larvae. Such maximally altruistic behaviour: sterile workers have zero personal fitness because the do not produce any offspring obviously — but they help greatly to the queen's reproductive efforts by their actions.

Natural selection points us to predict the behaviour of animals in fashion that raising the chances of survival and reproduction by their own, not those of others. But decreases its own fitness by behaving altruistically, so one who selfishly behave should be at a selective disadvantage. To view this, conceive that few group members of Vervet monkeys produce alarm calls after seeing the predators, but others do not. Another things being equal, they get an advantage latter. By denying selfishly to produce an alarm call, a monkey can decrease the probability that it will be attacked by itself, while helping others from the alarm calls at the same time. So we could imagine natural selection to prefer those monkeys who do not produce an alarm calls over those that do. But a puzzle arises immediately. How did the behaviour of giving alarm firstly evolve, and what is the reason that it do not been eliminated via natural selection? How the altruism existence can be settled with basic principles of Darwin?

Kin selection is the evolutionary stategy that at its own cost of reproduction and selection they prefers the reproductive fitness of the fellow of an organisms. Altruism will favor only when:

rB - C > 0, r = relativeness between altruist and recepient

B = recepient fitness benefit

C = cost of fitness to the altruist.