托福口语 Task 4

Today, we're going to discuss a fascinating concept in biology called 'mimicry'. Specifically, I want to focus on how certain harmless species have evolved to imitate dangerous ones for survival. This is known as Batesian mimicry. The main point here is that by looking like a harmful species, a harmless species can trick predators into avoiding them, even though they pose no real threat. Let me give you two examples from the insect world. First, consider the viceroy butterfly. It closely resembles the monarch butterfly, which is toxic to birds because of the milkweed it consumes. Birds that have tasted a monarch will avoid eating anything that looks like it, so the viceroy, which is actually harmless, benefits from this false warning. Second, think about the harmless milk snake. It has bands of red, black, and yellow, similar to the venomous coral snake. Predators learn to avoid coral snakes, and they extend that avoidance to the milk snake, even though the milk snake has no venom. In both cases, the mimic survives because predators generalize their fear.