TOEFLリスニング

🎧 リスニング原文

Narrator: Listen to part of a lecture in a biology class. Professor: Today we're going to talk about mimicry, specifically in butterflies. Now, you might think mimicry is simply about looking like another species to avoid predators. But it's more complex. There's Batesian mimicry, where a harmless species imitates a toxic one. For example, the viceroy butterfly mimics the monarch. Monarchs are poisonous to birds because they eat milkweed. Viceroys are not, but birds avoid them because they look like monarchs. Then there's Müllerian mimicry, where two or more toxic species evolve to look alike. This is beneficial because predators learn to avoid the shared pattern after one bad experience, reducing deaths for all species involved. Recently, researchers discovered that mimicry can also involve signals we can't see, like ultraviolet patterns. These patterns are invisible to us but visible to birds. So, the question is: how do these patterns evolve? Is it purely genetic, or does the environment play a role? Studies show that mimicry genes are often linked in clusters, which allows them to be inherited together. This is crucial for the rapid evolution of complex patterns. So, next time you see a butterfly, remember there's more than meets the eye.