托福口语 Task 3

In biology, the concept of 'mimicry' refers to the resemblance of one organism to another, often to gain a survival advantage. There are two main types: Batesian mimicry, where a harmless species imitates a dangerous one to deter predators, and Müllerian mimicry, where two unpalatable species evolve to look alike, reinforcing avoidance learning in predators. Mimicry can involve visual, auditory, or chemical signals and is a classic example of natural selection shaping adaptations.

Professor: Let me give you a concrete example from a study on tropical butterflies. Researchers observed two species of butterflies, both toxic to birds, living in the same forest. One species had bright red wings, and the other had blue wings. Initially, birds avoided both after tasting them once. However, when scientists introduced a third, non-toxic butterfly species with red wings, birds quickly learned to avoid all red-winged butterflies, including the harmless one. Interestingly, the red toxic butterflies and the blue toxic butterflies remained distinct. Over generations, the blue toxic butterflies began to develop red patterns too, so they now resemble the red species. This convergence helps birds learn to avoid them faster, as one warning signal is more efficient than two. This is a classic case of Müllerian mimicry, where both species benefit from looking alike.