TOEFL Listening

🎧 Listening Transcript

Listen to part of a lecture in a biology class. The professor is discussing animal communication. Professor: Today we're going to talk about a fascinating aspect of animal behavior: communication. Many animals use visual signals, like the bright colors of a peacock's tail or the dance of a honeybee. But some species rely heavily on chemical signals, called pheromones. These chemical messages can trigger a variety of responses, such as attracting a mate or warning of danger. For example, ants release pheromones to mark trails to food sources. When an ant finds food, it leaves a chemical trail, and other ants follow it. Interestingly, pheromones can also influence development. In honeybee colonies, the queen produces a pheromone that suppresses the development of ovaries in worker bees, keeping them sterile. However, if the queen dies, the lack of this pheromone allows some workers to develop ovaries and lay eggs. So, chemical communication is not just about immediate behavior; it can have long-term physiological effects. Now, let's consider how researchers study these signals. They often use controlled experiments, exposing animals to synthetic pheromones to observe reactions. This helps us understand the complexity of these silent conversations.