托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'biological altruism'—when an animal acts in a way that benefits another individual at a cost to itself. Now, you might think this contradicts natural selection, but there's a clever explanation: kin selection. The idea is that animals are more likely to help relatives because they share genes. Let me give you two examples. First, consider ground squirrels. When a predator like a hawk approaches, a squirrel will give a loud alarm call to warn others, even though this draws the predator's attention to itself, increasing its own risk of being attacked. However, the squirrels that hear the call are often its siblings or offspring, so by protecting them, the squirrel ensures its own genes are passed on. Second, take honeybees. Worker bees are sterile, but they spend their whole lives caring for the queen and her offspring. Since the queen is their mother and the new bees are their sisters, they share a large proportion of genes. By sacrificing reproduction themselves, they help raise more closely related siblings, which ensures the survival of their genetic line. So, in both cases, the apparent self-sacrifice actually promotes the animal's own genetic success.