การฟัง TOEFL

🎧 บทถอดเสียง

Listen to part of a lecture in a biology class. Professor: Today, we're going to talk about mimicry in animals, specifically how some species evolve to resemble others for survival. One fascinating example is the monarch butterfly and the viceroy butterfly. For years, scientists believed that the viceroy mimicked the monarch because the monarch is toxic to predators. The viceroy, they thought, was harmless but gained protection by looking like the toxic monarch. However, recent research has challenged this idea. Studies show that the viceroy is actually also distasteful to birds, though not as toxic as the monarch. So instead of a classic Batesian mimicry, where a harmless species mimics a harmful one, this case might be an example of Müllerian mimicry, where two or more harmful species evolve to look alike, reinforcing the warning signal to predators. This distinction is important because it changes how we understand the evolutionary pressures. It suggests that predators learn to avoid the shared pattern more quickly when both species are unpalatable. So, the next time you see an orange-and-black butterfly, remember that its color might be more than just beauty—it's a survival signal.