托福口语 Task 4

Today, we're going to talk about a fascinating concept in biology called 'mimicry'. Mimicry is when one species evolves to look or behave like another species, often to gain a survival advantage. There are two main types of mimicry: Batesian and Müllerian. Let me give you two examples to clarify. First, consider the harmless milk snake. It has evolved to have the same red, yellow, and black banding patterns as the venomous coral snake. Predators that have learned to avoid coral snakes will also avoid the milk snake, giving it protection even though it's not actually dangerous. This is Batesian mimicry, where a harmless species mimics a dangerous one. Second, let's look at the monarch and viceroy butterflies. Both of these species are distasteful to birds because they feed on toxic plants. Over time, they have evolved to look very similar to each other. This is Müllerian mimicry, where two or more unpalatable species share the same warning coloration, reinforcing the lesson for predators to avoid them. So, the key point is that mimicry serves as a defense mechanism, but the evolutionary reason differs based on whether the mimic is harmful or harmless.