Types of Behaviour

16/01/2011 § 1 Comment

Last class was our very last lecture in biology and because of this, some students in the class went into some kind of frenzy and started recording the lecture. It turned out to be useful because, at home, I was able to listen to everything that was said during class and even some things that I didn’t know I missed.

This class, we continued the last lecture, reviewed lions and talked about bees a lot again. (At the end of the class, there was a quiz with a DBQ that discussed bees and their altruism for each other.)

As review, lions live in prides and each gender behaves differently. The male lion usually behaves very selfishly, focusing on putting his genes in the next generation. His only interests are to raise his offspring, because they carry his genes. If he successfully keeps these offspring alive and healthy (successful) until they become adults and are ready for the next generation, then he has allowed his own genes to join the genetic pool: that male lion is successful. Females are all sisters in a pride and all act for each other, not as selfishly as the male lions behave. They are ‘friendly’ towards one another and hunt together and share the food, even caring and nursing each other’s cubs.

Basically, if we look at the scenarios genetically, all the behaviours make sense. Evolution and natural selection has favoured all behaviours that help genes prosper and exist in the next generation. (Which is why evolution and natural selection keep driving genes forward through time; evolution is for genes). Kin selection is a selection that is especially powerful in humans where blood is thicker than water. Kin selection wasn’t in the book but we learned in class that the more related you are, the more likely altruism is to be. Meaning, the more related an individual is to another individual, the more likely they’ll risk their own hides to save that other individual if they were dying (a la stick-figures-drowning style, as we saw in class).

Bees are a good example of altruism because every single bee in a hive works for the benefit of the hive. They sacrifice all of their time and energy to working for the hive, time and energy that could have been used looking for their own food, not the hive’s. The level of their relatedness defines their altruism as basically all bees in a hive are related to each other. The level of relatedness must be greater than the ratio of costs over benefits for an organism to be altruistic.

Altruism can sometimes be seen in humans. If the relationship with someone is higher (and if the person is familiar with that level of relatedness), then it’s more likely that an individual will risk their hide to save another person’s from drowning (a la picture of drowning stick-men, again). Altruism is influenced at unconscious levels.

Other kinds of behaviours are cooperating which is beneficial for all participants, and spitefulness where no genes are passed on in the next generation. Spitefulness is basically animal A doing wrong or harming (maybe killing, in some organisms’ cases) animal B because B hurt A first. As a result, neither animal’s genes get into the next generation but at least animal A is assured that B won’t have the chance to be better them him.

Moving a little closer to the essay question (Why are humans nice?), organisms like humans that live in groups that aren’t always related are nice to each other because both sides of the party benefit. As said in class, you scratch my back, I’ll scratch yours. Or, in the end, everyone wins.

This is seen in vampire bats, where the females that live together are all unrelated but live by helping each other and continuously feeding each other. Chimpanzees also cooperate together, even if they’re not related, because, since they all recognise each other and are familiar with one another, they know that all the chimpanzees in the group mean to help the group survive. (As a result, everyone in the group gets to eat). All behaviours that help genes get into the next generation are selected for by natural selection and evolution.

Humans, in particular, favour other humans depending on the traits they share because those traits determine if they’ll be an appropriate partner to have offspring with. If the Human B’s traits aren’t favourable (which means their genes aren’t favourable for Human A), Human A would most likely not want to have offspring with them. So when humans are nice, they show good traits; good genes, and these genes also show who’ll be a better altruist out of the population.

§ One Response to Types of Behaviour

  • Dave Ferguson says:

    Kari,

    Excellent job of contextualizing both kin selection and reciprocal altruism while providing examples of each, and connecting all of that to humans. I’ll miss your thoughtful blogs next semester!!

    Mr. F.

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