Yellowstone Wolves and Trophic Cascades

Yellowstone Wolves and Trophic Cascades

 

Source:Wikipedia History of Wolves in Yellowstone

I came across this video through Facebook and thought it was so good for a TOEFL subject and so fascinating too, that I decided to make a little listening exercise out of it.

This time, I will give you multiple choice questions which makes it closer to the TOEFL exam, in particular, the PBT.

As in the TOEFL exam, look at the questions as you listen - ignore the visuals until after you have done the questions, then watch again and enjoy the images! It is such a lovely, feel-good video!

Click on the link to the video here:

Yellowstone wolves 

Here are the questions:

1. What is this talk mainly about?

A The damage to Yellowstone caused by wolves
B The changes attributed to wolves to the ecosystem and physical geography of Yellowstone
C The animals that live in Yellowstone
D The habitats of all the different species in Yellowstone

2. A trophic cascade is

A a high waterfall
B the flow of rivers through a valley
C an ecological process starting at the top of the food chain and going to the bottom
D an ecological process to describe the change to the plains

3.  The reintroduction of wolves to Yellowstone in 1995 caused

A the deer population to increase in number
B the decline in the number of beavers
C the vegetation to grow back and the number of different species to increase
D more soil erosion

4. The rivers have become less ________ and the banks more __________

A polluted:unstable
B straight:rocky
C deep:steep
D meandering:stable

How did you do? Scroll down for the answers.....

1 B, 2 C, 3 C, 4 D