Migration and Altruism

by Jason Amores Sumpter
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animals will generally choose where to live based on food and mates. Now, some organisms will actually in their lifetime, move very great distances. This is known as migration. This is a long distance movement of a population, and it's usually associated with seasonal changes. However, organisms will migrate for a variety of reasons, like availability of food sources, differences in climate or for mating purposes. Now we'll actually see three interesting types of migration what we call piloting, which is basically the use of familiar landmarks to find their way. Compass orientation, where the organisms will actually have their movement oriented to a specific direction. And true navigation, which is the ability of animals to find their way as if they were looking at a map as if they had GPS or something. And one example of this is with sea turtles that have a no ability to sense the magnetic field of the earth, and they use that sense of the magnetic field to orient themselves. So you can basically, you know, blind full to sea turtle driving around, taking a bunch of back streets for a while. Throw it in the ocean and it'll still find its way because it has that ability of true navigation. And here you can see a herd of wildebeests migrating, and here you can see some migratory patterns of birds, and hopefully you realize how astounding some of these distances are that these birds will travel. Now. Altruism isn't very interesting type of behavior because it seems counterintuitive. In some ways it's a behavior that actually has a fitness cost to the actor that exhibits it. So the organism that exhibits the behavior receives a fitness cost, meaning there's a detriment to their fitness. And the recipient of this behavior will actually receive a fitness benefits. So why would an organism do this? Ifit's not seemingly in its own self interest. Well, Part of the explanation to this is something known as kin selection, which is an evolutionary strategy that favors the reproductive success of an organism's relatives. And you can see this in organisms like bees, for example. Now Hamilton's rule is a way of looking at altruistic behavior, and it basically says that when certain conditions are met, you're more likely to have an altruistic behavior, and those conditions are that the benefit to the recipient is going to be high. The cost to the actor is gonna be low. And it's also going to factor in something known as coefficient of related nous, which is the average number of genes that are shared between the individuals. So this is represented with the equation that I'm writing out here, and the idea is that the benefit is high enough and the coefficient of relatedness is high enough that it outweighs the cost to the actor. So if you're still wondering why, you know, we would see this type of behavior, why we'd see altruism. This guy Hamilton developed this idea. It's sort of ah, a different way of looking at fitness. And he calls it inclusive fitness. And this is basically, uh, a way of looking at fitness, where you're looking at the evolutionary success of an organism based on the number of offspring it produces, which is pretty standard and how we look at fitness. But it also includes how that individual helps its relatives produce mawr offspring than they otherwise would be able thio on their own. So this is basically a uhh sort of expanded view of fitness that takes into account the Ultra is ultra Ristic behavior that increases the offspring and the survival of the offspring of relatives of the organism. And so it's believed that these behaviors are seen because they might not directly spread on organisms genetics. But because it's happening with relatives, you know, those relatives air going to share a portion of that organism's genes. And so in this, uh, you know, in this sense, the organism is helping to pass on a portion of its own genes by helping its relatives, you know, though it's not directly passing on all of its genes. Now, an interesting idea that has sort of been extrapolated from this thinking is the idea of reciprocal altruism, and this is going to be seen between organisms that are not related. So, uh, you know, no relation there, Uncle Ruckus, no relation. And this is when an actor is going to temporarily reduce its fitness to benefit the recipients under the assumption that the recipient will return the favor some day. And this is, uh, for example, seen in communities of chimpanzees, and it's thought to in part explain some aspect of human behavior and altruism amongst humans. Now, one nice example that I want to leave you with of, uh, you know all of this altruism. All of this thinking is with prairie dogs. Prairie dogs arose. They live in big communities with lots of relatives and prairie dogs exhibit this behavior you see here where they kind of like scream basically to alert their community of the presence of a predator. And I don't know if you could tell, but there's some feathers back here. Prairie dogs have toe watch out for birds of prey, which love to eat them. So this is an example of altruistic behavior. Because by alerting their community by making this noise, these prairie dogs actually draw attention to themselves. So they put themselves at risk of predation at greater risk of predation, in fact, but it helps warn all their brows. And so that means their brows are more likely to survive. And so this is going to help with their inclusive fitness. That's all I have for this one. I'll see you guys next time