托福口语 Task 4

Today, we're going to talk about a fascinating concept in biology called 'mimicry'—specifically, when one species evolves to look like another for survival. There are two main types: Batesian mimicry, where a harmless species imitates a dangerous one to avoid predators, and Müllerian mimicry, where two unpalatable species share similar warning signals to reinforce learning in predators. Let me give you two examples. First, consider the scarlet king snake. It's non-venomous, but its red, yellow, and black bands closely resemble the venomous coral snake. Predators learn to avoid the coral snake's colors, and they also avoid the king snake—that's Batesian. Second, think about different species of stinging wasps, like yellow jackets and paper wasps. They both have black and yellow stripes and are both dangerous. By looking alike, they share the cost of teaching predators—each predator that gets stung once learns to avoid all similar-looking wasps, so both species benefit—that's Müllerian. So, mimicry isn't just about deception; it's a complex evolutionary strategy that can involve cooperation.