Authentic Lessons for 21st Century Learning

The Circle of Life

Food Webs

Morgan Myers | Published: June 8th, 2022 by K20 Center

  • Grade Level Grade Level 6th, 7th, 8th
  • Subject Subject Science
  • Course Course
  • Time Frame Time Frame 2-3 class period(s)
  • Duration More 120 minutes


Students will explore the flow of energy among living organisms by constructing a food web consisting of the organisms that inhabit a salt marsh. This lesson includes optional modifications for distance learning. Resources for use in Google Classroom are included.

Essential Question(s)

How does energy flow within an ecosystem? (Topical: How do food webs show energy being cycled among producers, consumers, and decomposers?)



Students watch a clip of Mufasa telling Simba about the circle of life and reflect on what a circle of life is to them.


Students research and become familiar with salt marshes before discovering more about the organisms that inhabit them.


Students sort the salt marsh organisms based on their diets and construct a model of energy flow among those organisms.


Students differentiate between various types of consumers and then experience a disruption to the energy flow model they constructed.


Students create their own scenario that disrupts the balance in the salt marsh.


  • The Circle of Life lesson slides (attached)

  • Organism cards (attached, one set per pair of students)

  • CER (Claim, Evidence, Reasoning) handout (attached, one per student)

  • Internet connectivity to read the salt marsh research websites (or print copies for students)

  • Paper

  • Scissors

  • Glue

  • Markers


Use the attached lesson slides to introduce the lesson title and Essential Question, on slides two and four. Transition to slide five and show the students the video titled, "Morning Lesson with Mufasa." Follow the previous link, also found in the notes on slide five and in the Resources at the end of this lesson.

After showing the video, go to slide six and introduce the Think-Pair-Share instructional strategy. Have students answer the following questions:

  1. Make a list of the foods that you ate at your last meal. Where did that meal ultimately come from?

  2. Name something you’ve done today that required your body to use energy. Where did the energy you used come from?

  3. What do you think Mufasa means when he says, "the Great Circle of Life?"


Show slide eight—What is a Salt Marsh? Let students know they will be asked to research this question. Provide the students with the following web resources to begin their research (full URLs are listed in the Resouces below):

  1. "What is a Salt Marsh?"—an article on the National Oceanic and Atmospheric Association (NOAA) website

  2. "Salt Marshes"—an article on the National Park Service website

  3. "What is a Salt Marsh?"—a PDF fact sheet by the New Hampshire Department of Environmental Services

You may print copies of these articles, or allow students to access and read them from Internet-connected devices in your classroom. As they read these materials, as students to employ a Categorical Highlighting strategy to identify key aspects of salt marshes.


Assign students to partners and display slide 10—Organism Card Sort. For this activity, have students use the Card Sort strategy to organize the Organism Cards into producer, consumer, and decomposer categories. Begin by handing out the Organism Cards introducing students to some of the organisms that live in the salt marsh. Each card also lists what the organisms eat. Define the categories of producer, consumer, and decomposer for the students, as shown on slide 10. Ask the students to sort the organisms based on their diet type given the information on the cards and then label the cards with the category P, C, or D (producer, consumer, or decomposer) on the card.

Go to slide 11—Salt Marsh Energy Flow. Have students continue to work in pairs, and ask them to use their Organism Cards to develop a model showing how energy flows among the organisms in the salt marsh (this will be their food web). They should arrange the cards as they see fit on a piece of paper or cardstock, then glue them down, and add any graphical features necessary to show energy flow (such as arrows).

At the beginning of our lesson, Mufasa mentioned eating the antelope. Go to slide 12—Food Chains. Show students the savannah food chain displaying this action. Define food chain as shown on the slide. Ask the students to identify the direction of the arrows (in the direction that the energy flows—from the organism being eaten to the organism consuming).

Continue to slide 13—Food Webs. Show students the savannah food web that displays the lion eating the antelope, but also many other food chains. Define food web as shown on the slide. Now, given this new information, have students make corrections or additions to their salt marsh food web as needed, such as changing the direction of their arrows.

Move to slide 14—Producers, Consumers, & Decomposer. Use slides 14–19 to have students identify which savannah organism has each type of diet, and then reveal what salt marsh organisms have that same diet type. Have students make corrections to any cards that are not categorized correctly.


Go to slide 21—Different Types of Consumers. Now that they know what a consumer is, have students differentiate between carnivore, herbivore, and omnivore. Help students define these terms using their prefixes as shown on the slide.

Continue to slide 22—Different Types of Consumers. Instruct the student pairs to label the consumers on the food web according to type by placing a C, H, or O (carnivore, herbivore, omnivore) on the line next to the "C". Reveal the correct categories for the salt marsh organisms and have students make any necessary corrections.

Go to slide 23—The Delicate Balance. Remind the students that Mufasa said everything exists together in a delicate balance. Ask the students what effect a disruption to the ecosystem would have on that balance by posing the following scenario: "Insecticides are widely used by many people to kill insects. These insecticides contain chemicals that are harmful to other animals and humans that live in the environment. After these chemicals are applied, they can travel to human water supplies and to neighboring ecosystems. Predict what would happen to the food web you have made if insecticides entered the salt marsh and killed the grasshoppers." Pass out one of the attached CER (Claim, Evidence, Reasoning) instructional strategy handouts to each student. Ask students to make their prediction about the scenario and justify it using the CER.

After they have finished, instruct the students to share their CER with their partner. After pairs have shared with each other, solicit volunteers to share a couple of answers with the class.


Go to slide 25—The Delicate Balance. Ask the partnered students to come up with another scenario that might disrupt the balance in the salt marsh. They need to:

  1. Describe the scenario.

  2. Identify the organism(s) directly affected by the introduced scenario and explain how their population is affected.

  3. Identify the organism(s) indirectly affected by the introduced scenario and explain how their population is affected.

  4. Reconstruct the food web based on this scenario (they can remove organisms if eliminated or add organisms if being introduced).

Use a Gallery Walk strategy to have students share their scenario and the food web they have constructed based on that that scenario.