Invasive Species Case Study

Name: _________________________________       Date: _____________

You may not notice it when you're out walking in the woods or around your local pond. But wherever you live, there's a good chance there are one or more plant or animal species that don't really belong there. These nonnative or invasive species have become an increasingly big problem worldwide.

What's the big deal? They may look like they fit in, but invasive species often cause havoc in an ecosystem. For one thing, they often crowd out native species that do belong there. They hog nutrients and resources and disrupt the natural balance of an ecosystem. Once they get a foothold, it's often very hard to get rid of them.

In this activity, you'll learn more about one particular invasive species causing big problems in the United States: zebra mussels.

You'll begin with a visit to the USGS Zebra Mussel page. Click the link for the Zebra Mussel fact sheet.

1. Look at the picture comparing the zebra mussel and the quagga mussel. How are they different?
   
   
   
   
2. Read the paragraph Identification (below the picture). Where are zebra mussels usually found?
   
   
   
   
3. Scroll to Native Range. Where are zebra mussels originally from? Use Google or other search engine to learn what countries the lakes and rivers mentioned are found in.
   
   
   
   
4. When were zebra mussels first found in those places?
   
   
   
   
5. Continue scrolling to the paragraph Nonindigenous Occurrences. How far had the mussels spread by the early 19th century?
   
   
   
   
6. Explain the cause of their spread in Europe.
   
   
   
   
7. List the countries in Europe where they're found.
   
   
   
   
8. Where and when were they first discovered in North America?
   
   
   
   
9. List all places the mussels spread to in North America after they got a foothold.
   
   
   
   
10. Scroll to Means of Introduction. How did the mussels first get into the Great Lakes?
    
    
    
    
11. How did the territory they inhabited spread so easily after they were first introduced in North America?
    
    
    
    
12. Next, read Impact of Introduction. Describe the impact the mussels have had on intake pipes at power plants.
    
    
    
    
13. How many of the mussels were found (per square meter) at one Michigan power plant?
    
    
    
    
14. List at least four other impacts the mussels have had in the United States, as described in the first two paragraphs of the Impact of Introduction secton.
    
    
    
    
15. Continue to the next paragraph. What effects do the mussels have on ecosystems they invade? Give specific examples.