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National Geographic Video
Strange Days on Planet Earth
Name _______________________
Date __________ Pd ___
Episode 3: PREDATORS!
These are some things to think about while you watch the movie – jot down some notes/answers to these
questions as you watch.
Lake Guri, Venezuela
1. What are the biologists in the motor boats in Venezuela doing in the first part of the video? What caused
this flood?
2. What is going on a few miles north at Lake Guri, Venezuela?
3. What is happening with the animals on Iguana Island? (Think of the iguanas and howler monkeys…)
4. What do the scientists propose as a theory for all of these changes that are taking place on these and other
similar islands?
5. How does this same idea affect areas like the one in which we live?
6. Why can’t we just put the predators back?
Yellowstone
1. What is wrong with the river? How is it different from pictures that we have of these stream banks from the
past?
2. What kinds of organisms used to be in Yellowstone (or used to be there in far greater numbers)?
3. In trying to figure out why the aspen trees are disappearing so rapidly, what factors did the scientists
originally suspect to be the cause of this ecological disaster? Why did they reject these ideas?
4. What did the scientists find when they took core samples of the trees and counted up the growth rings?
5. How does the proposed explanation for these changes tie into something that we studied earlier this year?
6. What are some positive effects that the wolves have on the ecosystem?
7. What are some negative effects or repercussions of the reintroduction of the wolves?
Coral Reefs – Discovery Bay, Jamaica
1. What kinds of organisms are the top predators in the sea, surrounding many coral reefs? (Back before they
disappeared in some ecosystems…)
2. How do they “look at the fossil record” of a coral reef? What did they discover?
3. What clues does the fish market provide to help explain the destruction of the coral reefs?
a. What does “fishing down the food web” mean?
4. What happened when large predators were taken out of the system, and how did this affect the coral?
(There are several steps in the “chain” that contributed to this topple of the coral reef ecosystems…what are
they?)
5. How has this impacted St. Lucia and the economics and cultural traditions there?
6. How have the Caribbean Islands attempted to “solve” the problems of overfishing and coral reef decimation,
and has it made a difference?