托福口语 Task 4

Today we're going to talk about a concept in animal behavior called 'biological clocks.' These are internal mechanisms that help animals time their activities to regular cycles in the environment, like day and night. But here's the interesting part: biological clocks are not just about responding to changes in light—they can also be influenced by other environmental cues, such as temperature. Let me give you two examples to illustrate this. First, consider the desert iguana. This lizard lives in the hot desert, where temperatures can soar during the day. The iguana is active in the morning and late afternoon, but it retreats to its burrow during the hottest part of the day. Its biological clock is actually set by temperature changes, not just light. When the temperature rises above a certain point, the clock signals the iguana to seek shade. Second, think about the honeybee. Bees use the sun's position to navigate, but they also need to time their foraging with the availability of nectar. Researchers found that bees can adjust their foraging schedule based on temperature patterns in the flowers. If the flowers produce nectar at a certain time when it's warm, the bees' internal clock helps them return to those flowers exactly when the nectar is available, even if the sun is hidden behind clouds.