1. What is the purpose of the lecture？
To illustrate the difficulty of determining whether a certain species needs protection under the Endangered Species Act
2. Why do some experts think the American eel should not be considered endangered？
They can survive a wide range of environmental conditions.
3. What did several government agencies conclude about the size of the American eel population based on their survey？
It will increase and decrease periodically.
4. What problem does the professor emphasize about the population surveys of the American eel？
They have not provided an adequate estimate of the overall population.
5. Why does the professor mention that the American eel is a catadromous species？
To help explain the difficulty in determining the true size of the American eel population
6. What does the professor imply about the physical transformation of the American eel when she says this：
“Then during the course of their lives， they go through a series of physical transformations which are interesting in themselves. I think there are something about that in one of your readings.”
They are not a subject she will discuss in her lecture.