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Lesson: Zebra Mussels Invade Chicago!!
Glencoe Biology: The Dynamics of Life
Unit 8, Chapter 27, Section 27.1
Context of Lesson
Students will complete this lesson after reading Chapter 27, section 27.1, “Mollusks”. This lesson could also be completed at some point in Unit 2, after learning about food chains. This lesson emphasizes the role an invasive species, such as the Zebra Mussel, plays in students’ everyday lives. Students analyze data of Zebra Mussel spread and predict what may happen to the country’s waterways if the Zebra Mussel continues to thrive.
Main goals/ Objectives
As a result of performing this investigation, students will be able to:
- Analyze empirical data and make inferences
- Make predictions about the future of the Zebra Mussels
- Identify Zebra Mussels and some of the damage they cause
Materials
Zebra Mussels Maps (student handouts)
Article on Chicago Zebra Mussels (student handouts)
Zebra Mussel transparency (included)
Transparency 67, Glencoe Biology
Crayons or markers for each group of four students
Examples of Zebra Mussels shells (available in large quantities from any Chicago-area beach)
Optional (Zebra Mussels Power Point presentation, Zebra Mussels Power Point Script)
Note to the Teacher
Links to several PowerPoint presentations with accompanying scripts about Zebra mussels are included in the resource section of this lesson. The teacher should refer to these PowerPoint presentations for his or her own information, OR the teacher can include all or parts of the presentations as part of the lesson.
Facilitation (40 minutes)
This lesson can be conducted during whole class discussion, with the article made into an overhead, or read silently by individuals, or read aloud by individuals. Questions 1-4 can be given to students as an assignment or can be whole-class or group discussion questions.
Homework
Students could be assigned the article on Zebra Mussel infestations in Lake Michigan for homework; however, completing section 27.1 is sufficient preparation.
Bell Ringer
Show studentsTransparency 67 from section 27.1 of the Glencoe text. Instruct students to answer the two questions in their notebooks.
LessonAsk studentsto share their answers to the two questions in the transparency.
Show students an overhead of the zebra mussel.
Ask students which mollusk from the transparency does the zebra mussel resemble? Expect students to answer that it resembles the clam or the oyster because it has a top and a bottom shell.
Instruct studentsto read the article on Zebra Mussels in Chicago (if not completed for homework). Students could work in groups to answer the questions, as a class or individually. If it is read during class time students can read quietly to themselves, selected students can read aloud or the teacher can read to the students while they follow along.
Ask students, after they have read the article,
- What does the picture in the article show?
- What are the things all over her?
- Why is she covered in Zebra Mussels?
- What is the artist trying to say? Is this really possible? NO!! Not for humans but certainly for other living things that live in the lake.
Handoutthe Zebra Mussel maps to each group of 4 students. Ask students to read the maps, which are observations made by scientists.
Ask students to color the 2007 and 2010 maps with what they infer will happen given the observations already made. Each group should also write a paragraph describing why they drew their maps the way they did. They should defend their ideas using information from the article and from the PowerPoint presentation, if shown.
Extensions
Students can continue to explore the Zebra Mussel infestation by considering the impact of the Zebra Mussels on the food chain in Lake Michigan. Information can be found in the resources section below.
Modifications/Adaptations
Since students ideally would be discussing their ideas in groups or as a class with the teacher’s guidance, the verbal nature of this lesson is well suited for students with special needs. Pairing challenged students with regular education students is also an appropriate accommodation if students will be working in pairs or in groups. Challenged students should be allowed to answer orally or to make drawings of their ideas.
Evaluation
Student answers to the questions about the article as well as their maps and paragraphs are evidence of student understanding.
Teacher Learning Platform
During professional development, teachers will experience and practice debriefing the nature of science component of this activity as well as other similar discussions about inquiry and the nature of science.
Resources
Zebra Mussel PowerPoint/Script: Go to the following website,
Scroll to the bottom of the page for access to the following PowerPoints and Scripts:
- Aquatic Exotics
- Aquatic Exotics in Wisconsin
- Invasive Species--Fact or Fiction?
- Mussel Menace...Zebra Mussels and You (RECOMMENDED)
- Protecting Boats and Motors from Zebra Mussels
- There Goes the Neighborhood...
Zebra Mussel Transparency
SOURCE: Science Net: The next generation of science news
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What is the zebra mussel doing to Lake Michigan?
Sep-22-2006
On a recent visit to Chicago, I noticed that Lake Michigan, close to shore, looks more like the waters of the Caribbean (crystal clear, light aqua color). When I grew up in the city years ago the lake was just a bucket of sludge. I'm told the change in clarity is due to zebra mussels flushed out of the bilges of tankers visiting from Asia. These mussels, I understand, consume the sludge and act like filters, creating the crystal clear waters we see today. Is this true, and will we soon see palm trees on Lake Shore Drive?
--Chris, New Hope, Pennsylvania
Cecil replies:
Palm trees, no. There's this thing in Chicago called winter that the zebra mussels haven't been able to do much about. But you heard right zebra mussels are filtering Lake Michigan's once-turbid water. The accompanying color change is due to an increase in Cladophora, a type of green algae that thrives on the sunlight that now penetrates farther into the lake's depths. Before you start planning any scenic snorkeling trips, though, let me tell you the bad news about what's happening to the lakes.
The zebra mussel is a freshwater bivalve that originated in Russia (it was reported in the Caspian Sea in 1769) and spread through much of northern Europe by the 20th century. The mussels were first spotted in the United States in 1988, allegedly having made their way here in the ballast water of one or more transoceanic ships. When such water was mistakenly dumped into Lake St. Clair (between lakes Erie and Huron), the aquatic life within--including, apparently, zebra mussels--was released to the environment. Since then the mussels have spread throughout the Great Lakes, much of the Mississippi River system, and even to freshwater ponds and rock quarries.
While zebra mussels arguably have made the lakes prettier, in other respects they're a pest. A female can lay more than 100,000 eggs in a year; having few natural predators, the mussels accumulate quickly, reaching densities in the tens of thousands per square meter. With their small size (two inches tops) and tenacious grip they can easily foul equipment on ships, at water treatment facilities, etc--an engineer I know reports seeing them piled up six feet thick in a power plant water intake. Though not ranking with the giant squid as one of the terrors of the deep, zebra mussels lean on other aquatic wildlife pretty hard, too. Clams and crustaceans can end up with so many mussels attached that they're essentially smothered under the weight.
A zebra mussel is a living water filter, capable of processing about a quart per day. Levels of diatoms--certain single-celled algae--decreased between 82 and 91 percent in Lake Erie after zebra mussels were introduced; the Hudson River saw an 85 percent decrease in plankton after a similar invasion. Lake Michigan, which was formerly cloudy, has been cleared up noticeably by the hardworking little mollusks.
Cleaning up the lakes doesn't sound like a bad thing, but it's no unalloyed boon. By removing all that plankton, etc, from the water, zebra mussels steal food from native aquatic life, such as other invertebrates and fish. Then there's the cladophora. Always present in Lake Michigan and other Great Lakes, it was a problem years ago when farms and industry dumped high levels of phosphorus into the lake, leading to algae "blooms." Thanks to water-quality regulations, cladophora for a time was fairly well controlled. Then the zebra mussels showed up and began thinning out the lakes' protective murk. The algae went nuts. It's been shown that zebra mussel feces are a good food source for algae, making the problem worse.
A little algae may improve the lake's aesthetics, but a lot doesn't. Cladophora blooms result in large mats of the stuff washing up onto the beaches. It's not toxic to humans, but too much looks and smells gross. Worse, seagulls, ducks, and other birds feed on zebra mussels and such hiding in the clumps, resulting in higher levels of bird feces and E. coli and forcing more frequent beach closures. Desperate officials in Chicago this summer were reduced to signing up border collies to patrol city beaches and chase the birds away.
The long-term environmental impact of zebra mussels is uncertain, but since the chances of losing them are slim, we've little choice but to adapt. In that vein, a question I've been asked lately is whether zebra mussels are edible. The answer is a guarded yes. They're small and a bit tough, and even devotees of Ohio River delicacies usually won't eat them. After a lifetime of filtration, the mussels accumulate a lot of nasty stuff such as pesticides and heavy metals. Eh, you're thinking, maybe I'll stick to the catfish. OK, but skip any from the Kalamazoo River, which enters Lake Michigan's crystal clear waters near the resort town of Saugatuck. The EPA says they're toxic due to pollution with PCBs.
--CECIL ADAMS, Chicago Reader, Inc.
Page 1Zebra Mussel Maps 1988 - 2000
2007???2015???
Your job is to use the observations reported in the previous maps to make inferences about what the data for 2007 and 2015 could look like.
Page 1Zebra Mussel Map Predictions 2007-2015
Name ______
Group Members ______
Color the states that you think will have Zebra Mussels and, using red, mark the waterways that will be invaded by the mussels in the years 2007 and 2015. Be sure to use what you’ve learned about Zebra Mussels from the data maps and from the article to make your inferences.
20072015
Write a paragraph in the space below explaining why you colored the maps as you did. Use the observations in the 1988-2000 maps to support your inferences about where Zebra Mussels will be found in 2007 and in 2015.