托福口语 Task 4

Today we're going to talk about a fascinating concept in biology called 'mimicry', specifically when an animal evolves to look like another species to gain a survival advantage. There are two main types: Batesian mimicry, where a harmless species mimics a harmful one, and Müllerian mimicry, where two harmful species mimic each other. Let me give you two examples. First, consider the scarlet king snake, which is harmless but has bright red, yellow, and black bands—very similar to the venomous coral snake. Predators that have learned to avoid the coral snake also avoid the king snake, giving it protection without being poisonous itself. This is Batesian mimicry. Now, for Müllerian mimicry, look at the monarch butterfly and the viceroy butterfly. Both are toxic to birds because they feed on milkweed, which contains poisons. By looking alike, they reinforce the lesson for predators: if a bird eats one and gets sick, it will avoid both species. This shared warning signal reduces the number of individuals lost to learning predators. So, in summary, mimicry can either involve a harmless species copying a dangerous one, or multiple dangerous species copying each other, both leading to increased survival.