Estuary Food Webs
Notes
  • Created for students 4th-6th grade
  • Supplements any of the life science kits, such as: Environments or Structures of Life, or as a supplement for the Earth Science kit: Water
  • Takes approximately five to six class sessions of 30 to 45 minutes
  • Students will be using science notebooks. To learn more, go to: http://www.sciencenotebooks.org
  • This lesson is also available in PDF. Click here to download.
Big Ideas
  • All life is connected within an Estuary System.
  • Plants and animals are connected by how they get energy.
  • The sun is the source of energy for all living things.
Essential Questions
  • How do the plants and animals in an estuary get energy to live and grow?
  • How are plants and animals dependent upon each other within a system?
GLE Ties
1.3.8 Life Processes and the Flow of Matter and Energy: Understand that living things need constant energy and matter. W
Explain how plants and animals obtain food (e.g., plants make food from air, water and sunlight, nutrients; animals obtain food from other living things).
1.3.10 Interdependence of Life: Understand that that an organism’s ability to survive is influenced by the organism’s behavior and the ecosystem in which it lives. W
Describe how an organism’s ability to survive is affected by a change in an ecosystem (e.g. the loss of one organism in a food chain affects all other organisms in that food chain).
2.1.1 Questioning: Understand how to ask a question about objects, organisms and events in the environment. W
2.1.5 Communicating; Understand how to report investigations and explanations of objects, events, systems, and processes. W
3.2.4 Environmental and Resource Issues: Understand how humans depend on the natural environment and can cause changes in the environment that affect human’s ability to survive.
2 The student writes in a variety of forms for different purposes
2.1 Adapts writing for a variety of purposes
2.2 Writes for different purposes
2.3 Writes in a variety of forms

Vocabulary
Algae Bacteria Consumer W Decomposer W Decomposition
Ecosystem W Food Chain W Nutrient W Microorganism Photosynthesis
Primary Consumer Secondary Consumer producer Detritivore Detritus
Zooplankton Phytoplankton Plankton
Possible Misconceptions
  • A food chain is isolated (food chains are interconnected).
  • Nutrients that plants get from soil or water provide energy to the plant (plants are producers and get energy from the sugars they make during photosynthesis).
  • Energy is like matter and it is cycled and used over (energy can be stored, can change form, or be transferred to others, but it is ultimately lost from the system and systems need a constant input of energy, energy flows through a system coming in and leaving, but matter remains and changes form).
Instructional Strategies Notes for Teachers
Assessments
  • Notebook responses, discussion, observation, written report
LESSONS
Day 1 Food Webs Day 1 30-45 minutes
Lesson Description ROUTINE
  • The lesson will begin with the žEssential QuestionÓ posted and time for the students to respond to the question in their journals. žHow do the plants and animals in an estuary get energy to live and grow?Ó
MATERIALS NEEDED
  • Notebooks

PROCEDURE

  1. Have students share what they wrote in their journals.
  2. Give overview of the system of the food web using the PowerPoint žFood web of the EstuaryÓ. http://www.padillabay.gov/lessons/FoodWeb.ppt
  3. Have students draw a line under what they wrote (“line of learning” is a Notebooking strategy, see resources on Notebooking) and then add what they learned about how plants and animals get energy and matter that is needed to live and grow from the Power Point. Remind students to add any questions they may still have.

CHECKPOINT or ASSESSMENT
  • Students are expected to respond to the opening question in their notebook, to add what they learned and add questions they now have. Teacher checks notebook entries, paying particular attention to misconceptions and questions so that they can be addressed. These questions and new learning should be added to a class list so that they can be addressed and reviewed throughout the lessons. Other questions and new learning should be added as they come up.

REFLECTION and SHARING

  • Students are given the opportunity to add to their journal both new ideas about Estuary food webs, as well as any new question they may have.

CLOSURE

  • Have a few students share out “What was one new thing you learned or one thing you were reminded of because of this activity.”

NOTES and INSTRUCTOR REFLECTIONS

  • This first lesson is an overview of estuary food webs. It is meant as a starting point to teach about the flow of energy and matter and the interdependence that exists in an estuary system. It is also a way to check for misunderstandings and begin to address them.

INTERNET RESOURCES

Day 2 Food Webs Day 2 45-60 minutes
Lesson Description

INTRODUCTION or HOOK

  • Play the game, “Food Web!” Game is played in groups of 2-4. The object of the game is fit all the estuary organisms into one food web.

ROUTINE

  1. As a class, brainstorm several different food chains in the estuary food web. Notice how the chains overlap.
  2. Play the Food Web! game for 10-15 minutes.
    http://www.padillabay.gov/lessons/FoodWeb1.pdf
    http://www.padillabay.gov/lessons/FoodWeb2.pdf
  3. Explain the mini research assignment. Choose an estuary organism and begin research.

MATERIALS NEEDED

PROCEDURE

  1. Introduce the game žFood Web!Ó
    • Demonstrate how several organisms fit together.
    • Note that many cards will connect to the detritus cards.
    • Divide into small groups to play the game for 10-15 minutes.
    • If a group finishes early, they can take turns rearranging cards into different combinations.
    • Have students share about the game.

  2. Introduce the estuary organism research assignment. Share the planning sheet with students
    http://www.padillabay.gov/lessons/ReportWorksheet.pdf
    and then allow them to begin researching and taking notes.
  3. Students need to research:

    • Scientific name and common name.
    • Description of the organism
    • Is it a producer or a consumer?
    • What does it eat?
    • Who eats it?
    • What habitat does it live in (mudflats, rocky beach, sand beach, salt marsh)?
    • If it is intertidal, which tidal zone is it in (low tide, med. tide, high tide)?

  4. Provide students with a list of estuary organisms and provide time for students to select one for their research project. You may wish to organize the sign-up process to ensure that various organisms are selected and students do not select the same ones.

CHECKPOINT OR ASSESSMENT

  • Students are expected to participate in the game. Students will select an estuary organism and begin taking notes for their research activity.

REFLECTION and SHARING

  • Students will share which estuary organism they have chosen to research and will report their progress.

CLOSURE

  • Have a few students share out “What was one new thing you learned or one thing you were reminded of about estuaries because of this lesson.” Remember to add new items to the class lists.
Day 3 Food Web Day 3 45-60 minutes
Lesson 3 Description

INTRODUCTION OR HOOK

ROUTINE

  • Review different food chains in the estuary food web.
  • Students sketch an estuary food web in their journal.
  • Groups of 3-4 students work together to make a large poster of an estuary food web that includes the organisms they are researching.

MATERIALS NEEDED

  • Markers, poster paper, pencils, rulers, color pencils, books, pictures and information about organisms in an estuary environment. Student notes about organism they are researching.
PROCEDURE
  1. Ask students to again draw an estuary food web in their notebook. Review the roles of producers and consumers (herbivores, carnivores, detritivores).
  2. Students get into groups of 3 or 4. Their task is to create a poster of an estuary food web that includes the organisms that each group member is researching. They are free to include any other organisms they chose as long as they fit into their food web and have all components going from producers to consumers. Arrows connecting organisms should show the flow of energy in the system (i.e., from producer to consumer).
  3. Students are given approximately 30 minutes to cooperatively complete a drawing of an estuary food web. http://www.padillabay.gov/lessons/PosterRubric.pdf

CHECKPOINT OR ASSESSMENT

  • Students are expected to participate in their group contributing to the food web poster. Students will share these with the rest of the class and explain the flow of energy/matter in their drawings.

REFLECTION and SHARING

  • Student groups will share their posters of estuary food webs. Students are given the opportunity to add to their notebook both new ideas about Estuary food webs, as well as any new question they may have (remember to add ideas to class posters as well.)

CLOSURE

  • In journals, students write one new thing they learned or one thing they were reminded of about estuaries because of this lesson.

NOTES and INSTRUCTOR REFLECTIONS

  • This third lesson is an opportunity for students to make a visual of the introductory lessons of estuary food webs. It is meant to give those students that are visual learners an opportunity to physically put down what they have been learning.
Day 4 Food Web Day 4 30-45 minutes
Assessments
  • Research report on an estuary organism. (see rubric in day 2)
Lesson 4 Description

Students are given time to work on their reports.

CHECKPOINT OR ASSESSMENT

  • Student groups will share their posters of estuary food webs. Students are given the opportunity to add to their notebook both new ideas about Estuary food webs, as well as any new question they may have (remember to add ideas to class posters as well)

CLOSURE

  • Students will have a few moments at the end of the session to reflect in their notebook to reflect on their progress, they should make mention of how they have used their time and what goals they have for their next work session. They should score their work on a scale of 1-4 as to their engagement in the activity. This is recorded in their notebook.
Day 5 Food Web Day 5 30-45 minutes
Assessment
  • Written responses in notebooks.
  • What can happen if water that has high levels of pesticides gets into an estuary?
  • Scenario questions
Lesson Description

INTRODUCTION OR HOOK

  • Share pictures of algae blooms as well as oil slicks, and other pollutants in estuaries. You could also include a Washington state Department of fisheries notice of a closed beach due to high levels of pollutants.

ROUTINE

  • Students write a response in their notebook to the following question: What can happen to an estuary if it is exposed to water with high levels of pesticides?
  • Allow time for students to respond and then share what they think could happen. Record these ideas on a piece of chart paper or whiteboard.
  • Share information with the students about Biological Magnification (see below)

MATERIALS NEEDED

  • Pictures of beaches impacted by hazardous runoff
  • Signs of close beaches
  • information about high toxin levels at different beaches in estuaries.

PROCEDURE (I do, We do, You do)

    Share the following information with students and discuss what their thoughts are. After discussing the information about Biological magnification have students respond to the following questions in their journal.
      1. What are some alternative ways to control insects other than using chemical pesticides?
      2. How could DDT be found in areas that had never been sprayed with DDT?

    Biological Magnification is an increase in the concentration of toxins such as pesticides at each level of the food chain. The food chain transfers not just energy from one step to another it also transfers the matter from the previous plant or animal consumed and this includes any toxins, such as: pesticides and heavy metals they might have.

    The most talked about pesticide that has caused trouble in estuaries is DDT. DDT was first developed and used during World War II. It was thought to be a great benefit to humans because it would kill pests to humans like lice and mosquitoes. Soldiers would spray DDT directly on their bodies to get rid of lice and it would be sprayed from trucks and airplanes in great amounts to kill mosquitoes. Mosquitoes were not just a pest but also a serious health problem because they were a carrier of serious diseases such as malaria.

     The most talked about pesticide that has caused trouble in estuaries is DDT. DDT was first developed and used during World War II. It was thought to be a great benefit to humans because it would kill pests to humans like lice and mosquitoes. Soldiers would spray DDT directly on their bodies to get rid of lice and it would be sprayed from trucks and airplanes in great amounts to kill mosquitoes. Mosquitoes were not just a pest but also a serious health problem because they were a carrier of serious diseases such as malaria.

    People who sprayed DDT to kill insect pests like mosquitoes and lice were careful with the amount they used so it would not kill fish or other animals. What they didn’t know was the process of Biological Magnification. While the levels being sprayed were not high enough to kill the animals directly, the levels were building up in plants and animals that were eaten by others. These levels of DDT would eventually build to high enough levels within consumers that it would kill them.

    The process goes like this: DDT is picked up through food and water and is stored in fat cells. An animal like an oyster or clam may pick up a small amount of DDT from eating the detritus (decaying dead stuff). Next, a small fish or crab that then eats a maybe 10 of the oysters and/or clams contaminated with DDT.  The fish or crab now has about 10 times the amount of DDT that the clam of oyster had. Along comes an osprey that eats 10 fish. That osprey now has 10 times the amount of DDT as one of the fish had or 100 parts DDT. (10 fish each with 10 parts DDT is equal to 100 parts DDT for one osprey). The spraying of DDT that was thought to be harmful only to the pesky insects was indirectly poisoning the osprey.

    Biologists discovered that many shore birds, including osprey were unable to successfully reproduce after widespread use of DDT. It was discovered that the DDT affected the eggs that were being laid. The shells of the eggs were very thin and would break as soon as the parents tried to sit on them for incubation. The decline in the bird population was rapid and serious.

    DDT has been associated with cancer in mice. It also is known to interfere with the reproduction in many other organisms. Because of the harmful effects of DDT it is no longer used in the United States.

    Although it is not widely used in other places in the world it is still being used and contributing to biological magnification. In addition to the countries still using DDT there is a significant concentration of DDT still lying at the bottom of the ocean. This concentration is being consumed by bottom feeders in the ocean and continuing the problems associated with Biological Magnification. The United States does not use DDT, however there are still other pesticides used that cause similar problems.

CHECKPOINT OR ASSESSMENT

  • As an assessment of what they have learned so far about estuary food webs, have students complete the following scenario as an assessment. Be sure to remind students that a food chain is just a small part of a food web and that energy and matter are transferred throughout the food chain/web as plants and animals are consumed.
  • Scenario: A marine scientist has been investigating levels of DDT and has reported those levels for a single food chain in the estuary food web. Her results are as follows:
  • Concentration of DDT (parts per million):

  •                                                              Water 0.0005
                                                                 Plankton 0.04
                                                                 Clams 0.23
                                                                 Flounder 2.07


    • The clams eat the plankton. The flounder eats the clams. A fish eating bird such as the eagle then eats the flounder.
  1. Why does the clams have so much more DDT (parts per million) than the plankton?
  2. Answer: the clam is higher on the food chain than the plankton and as it consumes water and plankton, it takes in all of their matter, energy, and toxins.

  3. If the eagle eats 8 flounder, how much DDT would end up in the eagle?
  4. Answer: if an eagle eats one flounder it will receive 2.07 parts per million of DDT, however if it eats 8 you need to multiply 2.07 by 8 to receive an answer of 15.56 parts per million.

  5. Which level of producer or consumer (producer, primary consumer, secondary consumer, or tertiary consumer) would contain the highest level of DDT? Explain why.
  6. Answer: a tertiary consumer, as it the highest on the food chain will receive the highest levels of DDT as it consumes organisms with high levels and this adds up quickly, for example if you are a primary consumer eating plankton, it takes a large amount of plankton (over fifty) to reach the same levels as an eagle eating one flounder.

  7. Which level of producer or consumer would have the lowest levels of DDT? Explain why.
  8. Answer: Producers and primary consumers will have the lowest levels of DDT at they are lower on the food chain and this results in the lowest build-up, for example: consumers will receive DDT build-up from water which as a low level of DDT and primary consumers eat things lower on the food chain that do not have a large concentration of DDT, such as plankton.

REFLECTION and SHARING

  • Students revisit the questions and share out as a whole class.  Encourage students to add notes from this sharing in their notebooks and provide time for students to share any of the new learning.

CLOSURE

  • Collect scenario papers.

NOTES and INSTRUCTOR REFLECTIONS

  • This fifth lesson is an opportunity for students to see the effects of contaminates entering the estuary and the impact those have on the organisms in the estuary. It will also show how humans are a part of the estuary system.
Day 6 Food Webs Day 6 30-6- minutes
Assessment
  • Research report on an estuary organism.
http://www.padillabay.gov/lessons/ReportWorksheet.pdf
Lesson Description ROUTINE
  • Students respond in their notebook to the question, “What is the most important thing you have learned about estuaries?”
  • Students then share their research reports with the rest of the class. Before sharing their reports, students should complete the rubric and make any needed modifications to ensure that their projects are quality work. During sharing, students will have a rubric in front of them and are encouraged to give constructive feedback to their peers. Both student and teacher will evaluate the research according to the rubric.

MATERIALS NEEDED

  • Completed research reports
  • Notebooks

PROCEDURE

  • Students give an oral report on their research and score themselves. Students are given between 5-10 minutes to give their report with 3-5 minutes for feedback from the class.
  • Provide students with the opportunity to publish or share their work with others:
    • post reports in the school library or other display location
    • post reports to your district or class web page
CHECKPOINT OR ASSESSMENT
  • Students are expected to give their research report orally sharing any visuals they have prepared. Students are expected to respectfully provide feedback to their peers. Students complete a self-evaluation and are evaluated by the teacher.
Modifications and Extensions MODIFICATIONS
  • Ensure that collaboration teams are constructed to support student success
  • Provide extra scaffolding and assistant for students that are unable to work independently, such as: provide research materials, hi-light important information, ensure that reading level is appropriate for students
  • Require more frequent check points for some students to ensure that research and notebooks are completed accurately

EXTENSIONS

  • Have students write letters to the local newspaper to share the plight of the estuary and its organisms and perhaps things that people can do to help
  • Create an informational website aimed at a particular audience (other students, adults, business people, etc.) to help others realize the need to think carefully about the choices we make and how we are connected to the environment
  • Develop some educational materials to help students and other learn about the estuaries and how we impact them, such as: a modified estuary game that includes the effect of pollutants, an estuary poster that shares information about organism and their needs, etc.