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. Now, there are two main types of mimicry that I want to discuss: Batesian mimicry and Müllerian mimicry. Let me give you some examples. First, consider the harmless king snake. It has evolved to have the same red, yellow, and black banding as the venomous coral snake. Predators that have learned to avoid the coral snake will also avoid the king snake, even though it's completely harmless. This is Batesian mimicry, where a harmless species mimics a dangerous one to fool predators. Second, let's look at two different species of poisonous butterflies, the monarch and the viceroy. Wait, actually, both of these butterflies are toxic, and they both have similar orange and black patterns. By looking alike, they share the cost of teaching predators to avoid them. If a predator eats one monarch, it learns to avoid all butterflies with that pattern, which benefits both species. This is Müllerian mimicry, where two or more defended species mimic each other to reinforce the warning signal.