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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 students Transparency 67 from section 27.1 of the Glencoe text. Instruct students to answer the
two questions in their notebooks.
Lesson Ask students to 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 students to 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
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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,
1. What does the picture in the article show?
2. What are the things all over her?
3. Why is she covered in Zebra Mussels?
4. 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.
Handout the 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,
http://www.uwex.edu/erc/AquaInvHandbook.html
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...
http://ag.ansc.purdue.edu/EXOTICSP/zebra_mussel.htm
http://www.mlive.com/newsflash/regional/index.ssf?/base/news39/116343774577230.xml&storylist=newsmichigan
http://glrc.org/story.php3?story_id=3213
http://www.nature.ca/rideau/e/images/143-zm.gif
Zebra Mussel Transparency
SOURCE: Science Net: The next generation of science news
http://epistemicgames.org/cgibin/coweb/science.net.cgi?REQUEST=print_display&LOCATION=125
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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 onceturbid 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.
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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
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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.
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Zebra Mussel Maps 1988 - 2000
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Zebra 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.
Zebra Mussel Map Predictions 2007-2015
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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.
2007
2015
Write a paragraph in the space below explaining why you colored the maps as you did. Use the observations in the 19882000 maps to support your inferences about where Zebra Mussels will be found in 2007 and in 2015.