托福口语 Task 4

Today we're going to discuss a fascinating concept in animal behavior called 'biological altruism.' This refers to behaviors where an animal acts in a way that seems to reduce its own chances of survival or reproduction, but benefits others. At first glance, this seems to contradict natural selection. However, biologists have found that such behaviors can actually evolve if they help close relatives pass on shared 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. But because the squirrel's relatives—its siblings, cousins, and offspring—are nearby, the warning helps them escape. Those relatives share many of the same genes, so the squirrel's genes are still passed on indirectly. Second, think about honeybees. Worker bees are sterile; they don't reproduce at all. Instead, they spend their lives foraging, building the hive, and defending it by stinging intruders. When a worker stings, it dies, but it protects the queen, who is its mother. The queen produces many new workers, each carrying the worker's genes. So, by sacrificing itself, the worker ensures its genetic material is carried into the next generation through the queen.