Trophic Cascade…

The original version of this video has been watched over 44,000,000 times so you may already have seen it. It is worth watching. It shows the subtle effects that altering one aspect of a food chain can have on other parts of the habitat. In this case, it is an entirely positive story about the reintroduction of wolves to Yellowstone Park. The behaviour of the wolves, as top predators, alters the behaviour of the other animals that live in the park. This then alters the growth of plant life and increases the diversity of life by allowing organisms to occupy their own niche within the environment. Even though the wolves kill and eat other animals, their presence actually increases the variety of life. It is an important concept called trophic cascade.

.

Questions…

1. What trophic level do (a) trees, (b) deer and (c) wolves occupy?
2. Name an omnivore mentioned in the video.
3. Suggest one way in which wolves are typical mammals.
4. The film also mentions the four other classes of vertebrate. Name one.
5. What does the word ecosystem mean?
6. Suggest an animal (either from the film or your own knowledge) that is an ecosystem engineer.