Engage:
The teacher will begin the lesson by showing the students a picture of a bear, a fish, and a plant from a pond, or lake.
Ask the students: What does each picture have in common with the other? Solicit answers from the students and begin charting the students answers as the students respond.
Explore:
Ask the students to spread out around the classroom making a large circle. After the students make a large circle around the room, begin passing out the animal, plant, and insect picture cards.
Examples of picture cards can be found at:
Each student should receive one picture card.
After the teacher issues an animal, plant, or insect card to the students, ask the students to name the organism they have on their cards. [It would be helpful if the teacher prints out picture cards with the animal or plant name(s) already printed on the card. This will ease the student's understanding of the animal, plant, or insect.]
Before beginning the food web game, explain to the students that they will be making connections from one organism to another by tossing a ball of yarn from one person to another. Explain to the students that as you begin the game you will call a student's name before tossing the loose end of the ball of yarn to the student.
After making the connection, the student holding the ball of yarn should call the name of the fellow student he or she is tossing the ball of yarn to; make more connections (for example, teacher: plant card; student: rabbit card; student: fox card).
The game should continue until all students have made a connection using their animal/plant/insect cards. As the students toss the ball of yarn throughout the circle, ask the students the following questions:
- What is being transferred from organism to organism? (energy) Provide the students with a real-world situation: If you're hungry and your mother prepares your favorite dinner, what do you think is going to happen to your body as you eat the food? (Your body will gain strength and energy from the food being eaten or consumed.)
- What does the yarn represent? (the flow of energy or energy flowing from one organism to another) Explain to the students the ball of yarn represents energy and how energy flows from one organism to another. Ensure that the students understand that the yarn represents the arrows in a food web pointing from the organisms being eaten to the organisms eating it. Provide a brief explanation as to how this energy is broken down.
After the class finishes the game ask the students:
- What have we created using the pictures and the ball of yarn? (a food web model)
As the students answer, point out to the students the interconnections and graphical representation of what eats what. Explain how the food web begins as a food chain and grows into a food web (refer to the example of the bear, fish, and plant). Reinforce the idea that energy is being transferred from one organism (producer) to another organism (consumer) as one organism eats the other.
Explain/Research:
Allow the students to keep the picture cards. Ask four student volunteers to come to the front of the classroom with their picture cards. Ask the students if they have ever heard the terms producer, consumer, decomposer, and scavenger. Allow the students to respond.
As the students respond, chart their answers (definitions) on chart paper. After the students' responses are recorded, ask the four volunteer students to hold up their picture cards. Ask the students if they are able to identify the decomposer, scavenger, producer, and consumer on the picture cards.
If the students respond incorrectly, guide the students' responses by showing the students the connections between the consumer, producer, decomposer, and scavenger. Point out to the students that some of the organisms may have more than one role in the food web. If the students' cards are not sufficient to match the four terms, ask for other volunteers to come up and join the group until the students have gained an understanding of the four terms.
Review the engaging activity chart with the students. As the teacher reviews the chart, point out to the students that the three organisms make up a food chain or an ecosystem. Explain to the students the definition of an ecosystem. State to the students that a food chain always begins with plants (producers).
Ask the students, Where do plants get their food and energy? (the sun and through photosynthesis) Prompt the students to take the discussion to the next level. If a squirrel eats plants and a snake eats the squirrel, which organism is the consumer? (both)
Explain to the students that both organisms are needed to create an ecosystem. Allow the students the opportunity to play the ecosystem game: http://to.pbs.org/28SWgyH. Reinforce the difference between a food chain and a food web.
Extend the discussion by asking the students to compare a food chain to a food web. Have the students create a Venn Diagram inside of their science notebooks. The students should use the Venn Diagram to record their answers.
The teacher will introduce the students to Explore Learning. The teacher will need to create a free trial account in order to use Explore Learning. Once the teacher has created a free account, view the Food Chain Gizmo: http://bit.ly/28OBc9J. You may use the gizmo for five minutes as a trial demonstration.
The students will use the gizmo to gain a deeper understanding of how a food chain ecosystem works. Allow the students to manipulate the gizmo. As the students manipulate the gizmo they should grasp the concept of how organisms depend on each other for survival. The gizmo is full of resources that the teacher may use to enhance and extend this lesson.
Elaborate:
Ask the students to get into groups of three and bring their organism cards to their groups.
Have the students create a pyramid foldable for the four terms (consumer, scavenger, producer, decomposer) from Dinah Zike's foldables. The pyramid foldable is located on page 16 of the pdf. The teacher should guide the students in making the pyramid foldable.
After the students construct the foldables, tell the students that they are going to label each section with a term (side 1: consumer, side 2: scavenger, side 3: producer).
After the students label each side of their pyramid foldable, allow the students to glue pictures that they used for the game in the appropriate sections. You may want to make extra copies as the students may want to glue several pictures in each section. As the students work together on their pyramids, circulate throughout the room checking for understanding.
Question the students' work as they complete their pyramid foldables. Encourage the students to use small pieces of yarn or draw arrows to show the flow of energy from the producers to the consumers to the scavengers.
As the students complete the pyramid foldables refer to the term decomposer. Initiate a conversation with the students on the role of the decomposer in a food web. Share with the students' pictures of decomposers. http://bit.ly/2916Ro5
Allow the students to add the pictures of decomposers to the pyramid foldable by attaching the pictures to string and using a hole-puncher to punch holes evenly around the bottom of the pyramid foldable.
The teacher may create a rubric to evaluate the students' pyramid foldables. Allow the students to share their foldables with the class and display the foldables around the classroom once the students are finished.