托福口语 Task 3

In biology, the concept of 'mimicry' refers to the resemblance of one organism to another, which provides a survival advantage. Mimicry often occurs when a harmless species evolves to look like a harmful or unpalatable species, thereby deterring predators. This form of protection, known as Batesian mimicry, relies on the predator's learned avoidance of the harmful species. The mimic gains protection without incurring the cost of producing toxins or defenses itself.

Professor: Let me give you a classic example from a rainforest in South America. There's a butterfly called the monarch butterfly, which is toxic because it feeds on milkweed plants. Birds have learned to avoid eating monarchs because they make them sick. Now, there's another butterfly, the viceroy, which is not toxic at all. However, over time, viceroys have evolved to look almost identical to monarchs—same orange and black patterns. When a young bird encounters a viceroy for the first time, it hesitates because it looks like the toxic monarch it may have already tried. The bird avoids attacking, and the viceroy escapes. So, the viceroy gains protection by mimicking the monarch's appearance, even though it has no actual chemical defense.