托福口语 Task 4

Today, I want to talk about a fascinating concept in biology called 'mimicry'—specifically, how some harmless species evolve to imitate dangerous ones for survival. This is called 'Batesian mimicry.' The main point 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. First, consider the scarlet king snake, which is harmless. It has bright red, yellow, and black bands, very similar to the deadly coral snake. Predators like birds learn to avoid the coral snake’s bright warning colors, and they generalize that avoidance to the king snake. So the king snake gains protection without being venomous. Second, there’s the hoverfly, which looks like a stinging bee. Although hoverflies have no sting, their yellow-and-black stripes and buzzing flight mimic bees. Birds that have had a bad experience with a bee will steer clear of hoverflies as well. In both cases, the mimic’s survival increases because predators mistake them for the dangerous model.