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 its own cost. But how does this evolve if it seems to reduce the actor's survival? The key is that altruism often occurs among relatives, which increases the chance that the helper's genes are passed on through shared ancestry. Let me give you two examples. First, consider ground squirrels. When a predator 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. However, the squirrels that hear the call are often its close relatives—siblings, offspring, or cousins. By saving them, the squirrel ensures that many of its own genes, which are shared with these relatives, survive. Second, think of honeybees. Worker bees spend their whole lives foraging and caring for the queen's offspring, never reproducing themselves. But since the queen is their mother and the new bees are their sisters, the workers are actually helping to pass on their own genes through their mother's reproduction. In both cases, the apparent self-sacrifice actually promotes the altruist's genetic success through relatives.