Narrator: Listen to part of a lecture in a biology class. Professor: Today we're going to talk about a fascinating adaptation in some deep-sea fish: bioluminescence. Now, you might think that bioluminescence is just for attracting prey or mates, but it also serves a defensive purpose. Take the hatchetfish, for example. It has light-producing organs on its belly that emit light matching the downwelling light from the surface. This makes the fish nearly invisible to predators swimming below, a technique called counter-illumination. Another example is the vampire squid, which, when threatened, releases a cloud of bioluminescent particles to confuse predators. But bioluminescence isn't just about hiding; it can also be used to lure prey. The anglerfish uses a glowing lure on its head to attract small fish within striking distance. Interestingly, these light-producing reactions involve a chemical called luciferin, which reacts with oxygen to produce light. The key point is that bioluminescence has evolved multiple times across different species, each with its own unique application for survival in the dark ocean.
❓ 質問 What is the main purpose of the lecture?
A. To explain how bioluminescence helps deep-sea fish survive
B. To describe the chemical process of light production in fish
C. To compare different species of deep-sea fish
D. To discuss the challenges of studying deep-sea organisms
✅ 正解
To explain how bioluminescence helps deep-sea fish survive
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
