托福口语 Task 4

Today, we're going to discuss a fascinating concept in animal behavior called 'biological clocks.' These are internal mechanisms that allow organisms to anticipate and adapt to regular changes in their environment, such as day and night, or seasons. Let me give you two examples. First, consider the grizzly bear. As autumn approaches, the shortening daylight hours trigger changes in the bear's brain, leading to increased food intake and fat storage. This prepares the bear for hibernation during winter, even before the temperature drops significantly. Second, think about the honeybee. Bees have a remarkable ability to remember the timing of when flowers open and release nectar. They visit specific flowers at exactly the right time of day, based on their internal clock, ensuring they get the most nectar. If a bee is kept in a constant light environment, it still follows this daily rhythm, showing that the clock is internal, not just a response to external cues. So, biological clocks are crucial for survival and efficiency.