托福口语 Task 3

In biology, the concept of 'mimicry' refers to the phenomenon where one species evolves to resemble another species in order to gain a survival advantage. This resemblance can be in appearance, behavior, or sound. Mimicry often occurs when a harmless species mimics a dangerous or unpalatable one to avoid predation, a strategy known as Batesian mimicry. Alternatively, two harmful species may mimic each other to reinforce warning signals, which is called Müllerian mimicry. The key is that the mimic benefits from the predator's learned avoidance of the model species.

Professor: Let me give you a concrete example from a study I conducted in Central America. We observed a species of harmless, non-poisonous butterfly called the viceroy. It closely resembles the monarch butterfly, which is toxic to birds because it feeds on milkweed. Birds that have eaten a monarch become sick and learn to avoid its bright orange-and-black pattern. Now, the viceroy has evolved a nearly identical pattern, even though it is not toxic itself. When a young bird encounters a viceroy for the first time, it hesitates because the pattern looks like the monarch’s. The bird remembers its bad experience with the monarch and leaves the viceroy alone. So the viceroy gains protection simply by looking like a dangerous species. This is a classic case of Batesian mimicry, where the harmless mimic benefits from the predator's learned fear.