托福口语 Task 4

Today, we're going to talk about a fascinating concept in biology called 'mimicry'. Mimicry occurs when one species evolves to resemble another species, often for protection. There are two main types: Batesian mimicry and Müllerian mimicry. Let me give you two examples. First, consider the harmless milk snake. It has bright red, yellow, and black bands, which closely resemble the venomous coral snake. Predators that have learned to avoid the coral snake also avoid the milk snake, giving it protection without being poisonous itself. This is Batesian mimicry, where a harmless species imitates a dangerous one. Second, think about different species of stinging wasps, like yellow jackets and paper wasps. Both are actually dangerous, but they share similar black-and-yellow warning colors. Because predators learn to avoid this pattern after one bad experience, all wasp species benefit from looking alike. This is Müllerian mimicry, where multiple dangerous species reinforce a shared warning signal, reducing the number of attacks on each individual. So, the main point is that mimicry can evolve in different ways depending on whether the imitator is harmless or also dangerous.