Listen to part of a lecture in a biology class. Professor: Today we're going to talk about mimicry, specifically Batesian mimicry. This is a phenomenon where a harmless species evolves to imitate the warning signals of a harmful species. For example, the monarch butterfly is toxic to birds because it feeds on milkweed, which contains toxins. Birds learn to avoid monarchs after tasting them. The viceroy butterfly, which is not toxic, has evolved to look very similar to the monarch. By mimicking the monarch's orange and black pattern, the viceroy gains protection from predators that have learned to avoid the monarch. However, there's an interesting twist. Recent research suggests that the viceroy may also be distasteful to some predators, meaning it's not purely Batesian mimicry. This is called Müllerian mimicry, where two harmful species resemble each other to reinforce avoidance learning. So, the distinction between these types of mimicry can be blurry. The key is whether the mimic is harmless or harmful. Now, let's consider the evolutionary pressures that lead to such mimicry...
❓ Вопрос What is the main point the professor makes about the viceroy butterfly?
A. It is a harmless species that mimics the monarch butterfly solely for protection.
B. It may not be purely Batesian mimicry because it could also be distasteful.
C. It has evolved to look like the monarch butterfly because of the toxins in milkweed.
D. It is an example of Müllerian mimicry because it is more toxic than the monarch.
✅ Правильный ответ
It may not be purely Batesian mimicry because it could also be distasteful.
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word
