托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'biological altruism' — where animals act in ways that seem to reduce their own chances of survival to help others. Now, why would evolution allow such behavior? The key is that these acts often increase the survival of close relatives, who share many of the same genes. So, by helping relatives, an animal is indirectly ensuring its own genes are passed on. Let me give you two examples. First, consider ground squirrels. When a predator approaches, a squirrel will give a loud alarm call, warning others to hide. This call, however, draws the predator's attention to the caller, making it more likely to be attacked. But because the squirrels in the colony are closely related — often siblings or offspring — the warning call protects its own genes in those relatives. Second, think of honeybees. Worker bees sting intruders to protect the hive, but stinging causes the bee to die. The hive is full of the worker's sisters, all sharing a high proportion of genes. By sacrificing itself, the worker ensures the survival of the colony, which carries on its genetic legacy. So, in both cases, apparent self-sacrifice actually benefits the animal's own gene pool through relatives.