托福口语 Task 3

In biology, organisms often develop specialized traits to survive in extreme environments. One such adaptation is thermoregulation, the ability to maintain a stable internal body temperature despite external temperature fluctuations. This is crucial for animals living in habitats with dramatic temperature changes, such as deserts or high mountains. Thermoregulation can involve behavioral strategies, like seeking shade or sun, or physiological mechanisms, such as altering blood flow or metabolic rate. These adaptations allow animals to function optimally and avoid fatal overheating or cooling.

Professor: Let me give you a concrete example from a desert lizard species. This lizard lives in the Sahara, where daytime temperatures can exceed 50°C, but at night they can drop below 10°C. To manage this, the lizard uses behavioral thermoregulation. In the morning, it basks on sun-warmed rocks to raise its body temperature quickly, which enables it to hunt insects. However, as the sun gets intense around noon, it retreats to a burrow or under a rock to avoid overheating. Interestingly, when the ground becomes scorching, it performs a 'thermal dance'—lifting its feet alternately to minimize contact with the hot sand. At night, it stays in its burrow, which retains some warmth, and reduces its activity. These behaviors keep its body temperature within a safe range, allowing it to survive in such an extreme environment.