Tangled Web of Life
By Katie Larson, Alliance for the Great Lakes, klarson@greatlakes.org
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By Katie Larson, Alliance for the Great Lakes, klarson@greatlakes.org
To download a printable version of this lesson plan, click on the image
We would greatly appreciate your feedback! Click here to complete a short survey telling us about your experience with this lesson plan.
Lesson Overview
Students make a yarn web of connections between Great Lakes species, discuss the complexity of the web and discover the impacts of changes to the web. Students will explore the feeding relationships in an ecosystem, as well as the different plants and animals that inhabit the Great Lakes. The focus is on native species, but the lesson also provides an opportunity to introduce invasive species to the yarn food web and highlight their impact.
Teacher Background
Food chains that show feeding relationships in an ecosystem are part of large and complex food webs. By exploring these relationships, students become familiar with the concept of food webs, as well as the different plants and animals that inhabit the Great Lakes. Non-native species are introduced, often accidentally, into new ecosystems. Hundreds of examples of non-native species (also known as exotic species) appearing outside of their native ecosystems are known from around the world. An “introduced species” is a non-native species that has been intentionally brought from its native ecosystem to a new one. Many times, non-native or introduced species cannot survive in the new ecosystem or, if they do survive, they don’t harm their new ecosystem. However, if the new species survives and spreads, it may cause harm to the native species populations, altering the ecosystem. Non-native species that cause harm to the ecosystem, to the environment, or to people are called “invasive species”. The Great Lakes have been altered and have adjusted to changes, including the introduction of non-native species, throughout history. In this lesson, students should think about how humans and other species have altered the Great Lakes.
Target Grade & Subject: Grades 5-8, Science
Duration: One 50-minute class period
Instructional Setting: Classroom
Advance Preparation
Pull out all 35 Creature Cards with asterisks (*) from the set of Creature Cards. Then set the 9 invasive species cards to the side. Depending on how many students you have, you may want to make sure you have enough cards for everyone. If you have a smaller size class (<20) you want to make sure to have organisms from each trophic level (e.g. phytoplankton, zooplankton, crustaceans, fish, birds and humans) to make sure you’ll make enough connections to form a “tangled web”.
Learning Objectives
At the end of this lesson, students will be able to:
1. List 5 or more connections between Great Lakes organisms in a food chain.
2. Diagram a Great Lakes food web with a minimum of 5 organisms.
3. Give examples of changes and their potential impacts on a Great Lakes food web.
Michigan Science Performance Expectation Addressed
https://www.nextgenscience.org/search-standards
MS-LS2-5 Ecosystems: Interactions, Energy, and Dynamics
Evaluate competing design solutions for maintaining biodiversity and ecosystem services.*
SEP: Science & Engineering Practices
https://ngss.nsta.org/PracticesFull.aspx
Engaging in Argument from Evidence
Engaging in argument from evidence in Gr. 6-8 builds on K-5 experiences and progresses to constructing a convincing argument that supports or refutes claims for either explanations or solutions about the natural and designed worlds.
DCI: Disciplinary Core Ideas
https://www.nextgenscience.org/overview-dci
LS2.A: Interdependent Relationships in Ecosystems
Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. (MS-LS2-1)
LS2.C: Ecosystem Dynamics, Functioning, and Resilience
Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.
CCC: Cross-Cutting Concepts
https://ngss.nsta.org/CrosscuttingConceptsFull.aspx
Stability and Change
Small changes in one part of a system might cause large changes in another part. (MS-LS2-5)
Materials & Quantities Needed per class and per student group
• Creature Cards with asterisks (*) from Great Lakes in My World K-8. Alliance for the Great Lakes. 2005.
• Cards with possible situations (positive or negative) that affects a species or ecosystem: (-) invasive or non-native species competing with native species for food, (-) drought, (-) new construction, (+) wetland habitat restoration, (+) comeback of yellow perch population
• Ball of yarn
• Masking tape (optional)
• Web of Life student journal page
• Tangled Web student journal page (1 per student)
Guiding Questions
• Which native species live in the Great Lakes?
• How are these species connected to and dependent upon each other?
• In what ways might invasive species change the ways species in the Great Lakes interact with each other?
ENGAGE:
1) Discuss food chains by talking about the food eaten by humans. For example, if we eat a fish, that fish has possibly eaten a smaller fish, which ate microscopic zooplankton, which ate microscopic phytoplankton, which gained its energy from the sun. Have students trace back an element from their lunches to see how these connections apply.
2) Give each student one Creature Card. NOTE: Using those from the aquatic ecosystem will work best (with asterisks).
Ask students to silently read their creature name on the top left of the back side of the card, and then the “who eats me?” and “what I eat” sections on the right side of the card. You can then have 1 student stand up and read theirs aloud to the class. If another person’s creature is mentioned, they should stand up silently. Have these students then each say their creature names aloud. If other students hear a creature’s name that is in either the “who eats me?” or “what I eat” section of their card, they should silently stand up as well. Then, the new creatures that stood up should each say their creature names. Continue until all or most of the students are standing.
3) Show students examples of various Creature Cards that make up a food chain. Here is an example: sunlight (not a card), green algae, diporeia, yellow perch, lake trout, humans. Diagram this with students, using student page “Web of Life”.
Expected prior knowledge: Students should be familiar with food chains and food webs.
EXPLORE:
1) Have students sit in a circle and announce the names of their organisms. Make sure everyone understands what all the organisms are.
2) Holding the ball of yarn, tell students that you represent the sun. You will give your energy to one of the plants (e.g., algae) by holding onto the end of the yarn and passing the ball to a student with a plant card. When a student receives the ball of yarn, she/he should hold onto one end, and pass the ball to a student with the card of a species that her/his organism could eat OR be eaten by. It is VERY IMPORTANT that students realize that it can go to the species that eats their creature OR to a species their creature eats. Otherwise, a food web will not be successfully created. For example, the algae could pass the yarn to a zooplankton, who could pass it to a forage fish, and so on. Likewise, the fish could pass it back to something else it eats. Students look at the backs of their cards to determine what the species eats or is eaten by. Pass the yarn until it has reached everyone at least once. This may involve some problem-solving. A web will form between the students. Some species may be included more than once. Continue the game to find new connections.
3) At this point, give a hypothetical situation (positive or negative) that affects a species. For example, if the walleye have been over-fished, have the “walleye” give a light tug on his/her piece of the yarn. Have students “tug back” when they feel the tug, raising their hands as they tug for a visual of the web interconnections. Another example would be yellow perch population declining due to invasive alewives eating their larvae.
4) For each species, at least two others will feel a tug on the yarn and eventually everyone will. Other positive scenarios could include: a comeback in the yellow perch population or wetland habitat restoration.
5) Now, introduce an invasive species to the food web, such as: zebra mussels have entered the food web, reducing the amount of food available for native fish; or round gobies have competed with other fish and eaten their eggs, reducing their quantities. Select a native species to be impacted, such as lake trout. Have “lake trout” drop the yarn and have the rest of the class readjust the web to account for the change.
Supporting students during exploration: Questions that the teacher could ask to guide the exploration.
• What did the yarn look like after it had been passed to everyone? A web.
• Why did it look like this instead of a straight line or circle? The food web connections are complex, like a web.
• What happened when one organism dropped the yarn-- did the web stay the same, fall apart completely, or something else? The rest of the web had to readjust. Other organisms were impacted, but the whole web did not collapse because it is complex enough that it can change and still survive.
• What would happen if more and more scenarios were introduced, eliminating more parts of the food web? The food web would ultimately look a lot different from the way it looked originally, and would be more simplified. Food webs that lack complexity are not as resilient to change as those with a diverse group of organisms.
EXPLAIN:
Use the top half of the student page Tangled Web for each student to create a Food Web Diagram. Have each student create a food web diagram that includes 5-8 Great Lakes organisms. The food web should include several food chains. Use arrows to indicate who eats whom, and include all types (decomposers, producers, herbivores, omnivores, carnivores, scavengers). Students may need to ask questions of others who had different Creature Cards.
ELABORATE:
Have students share their food webs in small groups, looking for similarities and missing connections. Students can add to their food webs, based on the additional information they gather by seeing other students’ food webs.
Supporting students during elaboration: Questions that the teacher could ask to clarify student thinking.
• What other organisms does each of these species impact?
EVALUATE:
Have each student write a brief explanation on the effects of changes in the food web when species’ numbers are reduced or a species is eliminated.
Supporting students during evaluation:
• Which other organisms is your species connected to within the food web?
• How might they be affected by changes in the ecosystem?
New Vocabulary
Food chain - a series of organisms that eat each other: Humans – Lake Trout – Perch – Sculpin – Zooplankton - Phytoplankton
Food web - a group of interacting food chains in a living community
Sources
Alliance for the Great Lakes. 2005. “Web of Life”, “Tangled Web” and Creature Cards. Great Lakes in My World K-8.
Chicago, IL.
Appendix
Supporting Materials:
Student journal pages “Tangled Web”
Creature Cards (PDF to print (https://greatlakes.org/wp-content/uploads/2019/07/Printable-Creature-Cards-PDF-Version-2019.pdf ), or set ordered from Alliance for the Great Lakes https://greatlakes.org/
Students make a yarn web of connections between Great Lakes species, discuss the complexity of the web and discover the impacts of changes to the web. Students will explore the feeding relationships in an ecosystem, as well as the different plants and animals that inhabit the Great Lakes. The focus is on native species, but the lesson also provides an opportunity to introduce invasive species to the yarn food web and highlight their impact.
Teacher Background
Food chains that show feeding relationships in an ecosystem are part of large and complex food webs. By exploring these relationships, students become familiar with the concept of food webs, as well as the different plants and animals that inhabit the Great Lakes. Non-native species are introduced, often accidentally, into new ecosystems. Hundreds of examples of non-native species (also known as exotic species) appearing outside of their native ecosystems are known from around the world. An “introduced species” is a non-native species that has been intentionally brought from its native ecosystem to a new one. Many times, non-native or introduced species cannot survive in the new ecosystem or, if they do survive, they don’t harm their new ecosystem. However, if the new species survives and spreads, it may cause harm to the native species populations, altering the ecosystem. Non-native species that cause harm to the ecosystem, to the environment, or to people are called “invasive species”. The Great Lakes have been altered and have adjusted to changes, including the introduction of non-native species, throughout history. In this lesson, students should think about how humans and other species have altered the Great Lakes.
Target Grade & Subject: Grades 5-8, Science
Duration: One 50-minute class period
Instructional Setting: Classroom
Advance Preparation
Pull out all 35 Creature Cards with asterisks (*) from the set of Creature Cards. Then set the 9 invasive species cards to the side. Depending on how many students you have, you may want to make sure you have enough cards for everyone. If you have a smaller size class (<20) you want to make sure to have organisms from each trophic level (e.g. phytoplankton, zooplankton, crustaceans, fish, birds and humans) to make sure you’ll make enough connections to form a “tangled web”.
Learning Objectives
At the end of this lesson, students will be able to:
1. List 5 or more connections between Great Lakes organisms in a food chain.
2. Diagram a Great Lakes food web with a minimum of 5 organisms.
3. Give examples of changes and their potential impacts on a Great Lakes food web.
Michigan Science Performance Expectation Addressed
https://www.nextgenscience.org/search-standards
MS-LS2-5 Ecosystems: Interactions, Energy, and Dynamics
Evaluate competing design solutions for maintaining biodiversity and ecosystem services.*
SEP: Science & Engineering Practices
https://ngss.nsta.org/PracticesFull.aspx
Engaging in Argument from Evidence
Engaging in argument from evidence in Gr. 6-8 builds on K-5 experiences and progresses to constructing a convincing argument that supports or refutes claims for either explanations or solutions about the natural and designed worlds.
DCI: Disciplinary Core Ideas
https://www.nextgenscience.org/overview-dci
LS2.A: Interdependent Relationships in Ecosystems
Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. (MS-LS2-1)
LS2.C: Ecosystem Dynamics, Functioning, and Resilience
Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.
CCC: Cross-Cutting Concepts
https://ngss.nsta.org/CrosscuttingConceptsFull.aspx
Stability and Change
Small changes in one part of a system might cause large changes in another part. (MS-LS2-5)
Materials & Quantities Needed per class and per student group
• Creature Cards with asterisks (*) from Great Lakes in My World K-8. Alliance for the Great Lakes. 2005.
• Cards with possible situations (positive or negative) that affects a species or ecosystem: (-) invasive or non-native species competing with native species for food, (-) drought, (-) new construction, (+) wetland habitat restoration, (+) comeback of yellow perch population
• Ball of yarn
• Masking tape (optional)
• Web of Life student journal page
• Tangled Web student journal page (1 per student)
Guiding Questions
• Which native species live in the Great Lakes?
• How are these species connected to and dependent upon each other?
• In what ways might invasive species change the ways species in the Great Lakes interact with each other?
ENGAGE:
1) Discuss food chains by talking about the food eaten by humans. For example, if we eat a fish, that fish has possibly eaten a smaller fish, which ate microscopic zooplankton, which ate microscopic phytoplankton, which gained its energy from the sun. Have students trace back an element from their lunches to see how these connections apply.
2) Give each student one Creature Card. NOTE: Using those from the aquatic ecosystem will work best (with asterisks).
Ask students to silently read their creature name on the top left of the back side of the card, and then the “who eats me?” and “what I eat” sections on the right side of the card. You can then have 1 student stand up and read theirs aloud to the class. If another person’s creature is mentioned, they should stand up silently. Have these students then each say their creature names aloud. If other students hear a creature’s name that is in either the “who eats me?” or “what I eat” section of their card, they should silently stand up as well. Then, the new creatures that stood up should each say their creature names. Continue until all or most of the students are standing.
3) Show students examples of various Creature Cards that make up a food chain. Here is an example: sunlight (not a card), green algae, diporeia, yellow perch, lake trout, humans. Diagram this with students, using student page “Web of Life”.
Expected prior knowledge: Students should be familiar with food chains and food webs.
EXPLORE:
1) Have students sit in a circle and announce the names of their organisms. Make sure everyone understands what all the organisms are.
2) Holding the ball of yarn, tell students that you represent the sun. You will give your energy to one of the plants (e.g., algae) by holding onto the end of the yarn and passing the ball to a student with a plant card. When a student receives the ball of yarn, she/he should hold onto one end, and pass the ball to a student with the card of a species that her/his organism could eat OR be eaten by. It is VERY IMPORTANT that students realize that it can go to the species that eats their creature OR to a species their creature eats. Otherwise, a food web will not be successfully created. For example, the algae could pass the yarn to a zooplankton, who could pass it to a forage fish, and so on. Likewise, the fish could pass it back to something else it eats. Students look at the backs of their cards to determine what the species eats or is eaten by. Pass the yarn until it has reached everyone at least once. This may involve some problem-solving. A web will form between the students. Some species may be included more than once. Continue the game to find new connections.
3) At this point, give a hypothetical situation (positive or negative) that affects a species. For example, if the walleye have been over-fished, have the “walleye” give a light tug on his/her piece of the yarn. Have students “tug back” when they feel the tug, raising their hands as they tug for a visual of the web interconnections. Another example would be yellow perch population declining due to invasive alewives eating their larvae.
4) For each species, at least two others will feel a tug on the yarn and eventually everyone will. Other positive scenarios could include: a comeback in the yellow perch population or wetland habitat restoration.
5) Now, introduce an invasive species to the food web, such as: zebra mussels have entered the food web, reducing the amount of food available for native fish; or round gobies have competed with other fish and eaten their eggs, reducing their quantities. Select a native species to be impacted, such as lake trout. Have “lake trout” drop the yarn and have the rest of the class readjust the web to account for the change.
Supporting students during exploration: Questions that the teacher could ask to guide the exploration.
• What did the yarn look like after it had been passed to everyone? A web.
• Why did it look like this instead of a straight line or circle? The food web connections are complex, like a web.
• What happened when one organism dropped the yarn-- did the web stay the same, fall apart completely, or something else? The rest of the web had to readjust. Other organisms were impacted, but the whole web did not collapse because it is complex enough that it can change and still survive.
• What would happen if more and more scenarios were introduced, eliminating more parts of the food web? The food web would ultimately look a lot different from the way it looked originally, and would be more simplified. Food webs that lack complexity are not as resilient to change as those with a diverse group of organisms.
EXPLAIN:
Use the top half of the student page Tangled Web for each student to create a Food Web Diagram. Have each student create a food web diagram that includes 5-8 Great Lakes organisms. The food web should include several food chains. Use arrows to indicate who eats whom, and include all types (decomposers, producers, herbivores, omnivores, carnivores, scavengers). Students may need to ask questions of others who had different Creature Cards.
ELABORATE:
Have students share their food webs in small groups, looking for similarities and missing connections. Students can add to their food webs, based on the additional information they gather by seeing other students’ food webs.
Supporting students during elaboration: Questions that the teacher could ask to clarify student thinking.
• What other organisms does each of these species impact?
EVALUATE:
Have each student write a brief explanation on the effects of changes in the food web when species’ numbers are reduced or a species is eliminated.
Supporting students during evaluation:
• Which other organisms is your species connected to within the food web?
• How might they be affected by changes in the ecosystem?
New Vocabulary
Food chain - a series of organisms that eat each other: Humans – Lake Trout – Perch – Sculpin – Zooplankton - Phytoplankton
Food web - a group of interacting food chains in a living community
Sources
Alliance for the Great Lakes. 2005. “Web of Life”, “Tangled Web” and Creature Cards. Great Lakes in My World K-8.
Chicago, IL.
Appendix
Supporting Materials:
Student journal pages “Tangled Web”
Creature Cards (PDF to print (https://greatlakes.org/wp-content/uploads/2019/07/Printable-Creature-Cards-PDF-Version-2019.pdf ), or set ordered from Alliance for the Great Lakes https://greatlakes.org/
New lesson plan ideas are welcome and will be uploaded as they are received and approved.
Instructions for submitting lesson plans for:
About invasive species,
About science and science careers
For information about submitting new lesson plans, please contact jchadde(at)mtu.edu
Lesson plan ideas from other web sites:
From Pennsylvania Sea Grant: 10 lesson plans about interactions of invasive species, biodiversity, and climate change
Creation of the above page of educational resources was funded in part by the Michigan Invasive Species Grant Program through the Departments of Natural Resources, Environmental Quality, and Agricultural and Rural Development.
This material is also based upon work supported by the National Science Foundation under Grant No. 1614187.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.