托福口语 Task 3

Mimicry is a biological phenomenon where one species evolves to resemble another species or object in its environment to gain a survival advantage. This resemblance can be visual, auditory, or chemical, and it often serves to deceive predators or prey. There are two main types: Batesian mimicry, where a harmless species imitates a dangerous one to avoid predation, and Müllerian mimicry, where two unpalatable species evolve to look alike, reinforcing avoidance learning in predators. Mimicry is a product of natural selection, as individuals with better resemblance are more likely to survive and reproduce.

Professor: Let’s take a real example from the rainforest. The harmless milk snake has evolved to look very similar to the venomous coral snake. Both have bright red, yellow, and black bands. But the order of the bands differs—coral snakes have red touching yellow, while milk snakes have red touching black. Predators, like hawks, learn to avoid the coral snake after a painful experience. Because the milk snake looks so similar, hawks mistake it for the coral snake and avoid it too. This is a classic case of Batesian mimicry. The milk snake gains protection without being venomous itself. Interestingly, in areas where coral snakes are rare, milk snakes have less distinct patterns, which shows that the mimicry is driven by the presence of the model species.