L3：
讲座
1. What is the lecture mainly about?
Similarities and differences between polar and tropical birds
How mammals tend to differ from birds in choosing a microhabitat
How feeding strategies based on climate can influence species diversity
Warning signs that indicate when a species is threatened with extinction
2. What are two points the professor makes about polar animals species with regard to the food they eat?（多选题）
They change their eating behaviors based on food availability
They can survive without food for long periods of time
They tend to need more food in the winter than in the summer
They look for food over a very wide area
3. Why does the professor discuss the arctic fox?（多选题）
To point out its effect on bird populations in polar regions
To identify an animals species affected by seasonal change
To illustrate the importance of microhabitats
To give an example of a generalist species
4. What reason does the professor give to support the claim that microhabitats lead to an increase in species diversity?
They have temperatures that are suitable for many species.
They reduce competition among species for the same food resources.
They allow individual species to spread throughout multiple ecosystems.
They prevent animals species destroying their food sources through overpopulation.
5. Why does the professor mention species extinction?
To emphasize a possible consequence of specialization
To point out the effect of human activity on polar habitats
To illustrate a downside of competition between different species D. To give a reason why animal species might change its microhabitats
6. What does the professor imply when she says this:
The student has guessed correctly
The student’s explanation is surprisingly original
The student has not understood her question
D. The student’s conclusion is logical but inaccurate
