The Role of Altruism in Evolutionary Biology

This concept challenges the traditional view of natural selection, which emphasizes individual survival and reproduction. Altruism can increase the fitness of a group or species, even if it reduces the fitness of the individual displaying these behaviors. Examples include animals warning others of predators at the risk of attracting attention to themselves or sharing food with others. Altruistic behaviors can be explained by the idea of kin selection, where individuals help relatives to ensure the survival of shared genes.

Listening transcript

Alright, today we're discussing altruism in animals, a fascinating topic in evolutionary biology. Let's consider the example of meerkats. These small mammals often have a sentinel, or look-out, while the rest of the group forages. The sentinel alerts the group to danger but risks being the first target of a predator. This behavior benefits the group, ensuring their safety, even though it's risky for the lookout. Another example is vampire bats. They often share blood meals with roost-mates who haven't fed. This sharing is crucial for survival because a bat might not feed every night. By helping others, they ensure that when they are in need, others will reciprocate, supporting the group’s overall survival and genetic success.

Speaking task instruction

Explain the concept from the reading and use the professor’s examples to show how it works. Preparation time: 30 seconds, Response time: 60 seconds.

Sample student response

Altruism in evolutionary biology is when an individual helps others but at a cost to itself. The reading says this behavior can improve the fitness of the group. In the lecture, the professor gives two examples. First, meerkats have a sentinel that watches for danger while others eat. The sentinel is at risk, but it keeps the group safe. Second, vampire bats share blood meals with bats that didn't eat. This means when one bat helps another, it might get help later. Both examples show how altruism helps the group survive, even if it's risky for the individual. This fits with the idea that helping relatives can pass on shared genes.