春骥 TOEFL Listening · Galapagos Tortoise Cactus

Questions

Question 1 Main Idea

What is the talk mainly about?

A The hunting practices that endangered tortoises in the Galapagos Islands B The process by which cactus seeds germinate in volcanic soil C A comparison between tortoise conservation and marine wildlife protection D How Galapagos tortoise recovery has benefited the island ecosystem

Question 2 Detail

According to the professor, why did cactus populations begin to struggle when tortoise numbers declined?

A The cacti were overgrazed by introduced species that replaced tortoises B The soil became too acidic for cactus seedlings to survive C Cactus seeds were no longer being dispersed effectively across the islands D Volcanic activity on the islands destroyed the cacti's natural habitat

Question 3 Inference

What can be inferred about the professor's view of single-species conservation programs?

A They are usually too expensive to justify the ecological benefits B Their value extends beyond the target species to the broader ecosystem C They only benefit the specific species being protected D They have failed to produce any measurable ecological improvements

Question 4 Vocabulary

The professor mentions that tortoises play a critical role in 'seed dispersal.' What does 'dispersal' mean in this context?

A The conversion of seeds into a more digestible form for animals B The spreading of seeds to new locations away from the parent plant C The protection of seeds from predators until germination occurs D The rapid growth of a plant population within a limited area

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When we talk about conservation success stories, we often focus on saving a single species from extinction. But today I want to show you how saving one species can actually reshape an entire ecosystem. Let's look at the Galapagos tortoise. These giant herbivores were once abundant across the islands, but hunting and introduced species reduced their numbers drastically. As tortoise populations declined, something unexpected happened: the cactus populations also began to struggle. Why? Because tortoises play a critical role in seed dispersal. When they eat cactus fruit, the seeds pass through their digestive systems and are deposited across the landscape in nutrient-rich droppings. Without tortoises moving across the islands, cactus seeds weren't spreading effectively to new areas. Now, thanks to intensive conservation efforts, tortoise numbers are recovering. And we're seeing a corresponding rebound in vegetation patterns. Young cacti are appearing in places where they had vanished. So what does this tell us? It reminds us that in ecology, species don't exist in isolation. The return of these large herbivores isn't just good news for tortoises—it's restoring the ecological balance that many plants depend on.