托福口语 Task 4

Today we're going to talk about a fascinating behavior in the animal kingdom: altruism, or when animals act in ways that benefit others at their own expense. This seems to contradict natural selection, which favors survival of the fittest. However, biologists have found that altruistic behavior can actually help an animal's genes survive, even if the individual doesn't directly benefit. One key explanation is kin selection. Here's the idea: if an animal helps its relatives, it's indirectly helping to pass on shared genes. For example, consider prairie dogs. When a predator like a hawk approaches, a prairie dog will give a loud alarm call to warn others, even though this draws the predator's attention to itself. Prairie dogs live in family groups, so by warning its brothers and sisters, the calling prairie dog is protecting its own genetic relatives, ensuring their survival. A second example involves ground squirrels. When a snake enters a burrow, a female squirrel will sometimes block the entrance to protect her pups inside, risking her own life. Again, because the pups share her genes, her sacrifice increases the chance those genes will be passed on. So, altruistic acts often target relatives, which makes evolutionary sense.