托福口语 Task 4

Today we're going to talk about a fascinating concept in biology called 'mimicry' – specifically, when one species evolves to look or behave like another species to gain an advantage. There are two main types: Batesian mimicry, where a harmless species imitates a dangerous one to avoid predators, and Müllerian mimicry, where two harmful species evolve to look alike, reinforcing each other's warning signals to predators. Let me give you two examples. First, consider the harmless milk snake, which has red, yellow, and black bands – very similar to the venomous coral snake. Predators learn to avoid the coral snake's bright colors, and they also avoid the milk snake, even though it's completely harmless. This is Batesian mimicry. Second, think about two species of stinging wasps – the European wasp and the common wasp. Both have black and yellow stripes and a painful sting. By looking alike, they share the cost of teaching predators to avoid them. If a predator gets stung by one, it will avoid both species in the future. This is Müllerian mimicry. So, the main point is that mimicry can evolve either to deceive predators or to cooperate with other species for mutual protection.