L3
讲座
1. What does the professor mainly discuss?（多选题）
Features of ecosystems that promote the spread of invasive species
The impact of Canada thistle on native animal species of the northwest United States
Methods that have helped control the growth or invasive plant at Yellowstone National Park
Reasons for the spread of Canada thistle in the northwestern United States
2. What is one consequence of climate change that has been beneficial for Canada thistle?
Increased moisture levels in the air
A decrease in animals that feed on Canada thistle
A decrease in the amount of moisture in soil
A change in the types of nutrients in soil
3. How has the spread of Canada thistle affected animals in the northwestern
United States?（多选题）
It has led to an increase in the gopher population.
It has caused many animals to become adaptive foragers
It has led to an increase in the variety of animal species inhabiting the area.
It has provided grizzly bears with a needed source of food.
4. What does the professor imply about the long-tailed weasel
It cannot feed on Canada thistle.
It is responsible for the decline in vole populations.
It has a mutually beneficial relationship with voles
Its diet has begun to include more plants.
5. The professor discusses ways of stopping the spread of Canada thistle.
What does she imply about the methods she discusses?
Climate change may cause some methods to become less effective
The best solution may be to combine several methods.
Some available methods would probably cause more problems.
Chemical sprays being developed are more likely to be effective than nonchemical methods.
6. Why does the student say this:
He is unsure about the relationship Canada thistle has to other invasive species.
He does not know why the professor is focusing on Canada thistle.
He is uncertain about why Canada thistle is considered an invasive species
He wonders why the book did not mention Canada thistle.
