Whole Earth Curriculum WEC

Lesson 01 — Matter and Energy Move Through a Food Web

Learners trace how matter and energy move from the Sun through a food web: producers make food, consumers eat, and decomposers recycle. They build a web with arrows that always point from the eaten to the eater, and connect it to real ecosystems around the world.

D06 P3: Intellectual & Cognitive Awareness D06.S2 55 minutes Draft

Objectives

Essential question

How do matter and energy move from the Sun through the living things in a food web?

producerconsumerherbivorecarnivoredecomposerfood chainfood webenergymatter

Materials

Standard materials

Low-tech / no-cost

Enriched / lab & device

Works in different contexts

A food-web diagram. At the top, a labeled Sun sends an arrow down to a grass plant labeled producer. The grass sends arrows to a grasshopper and a rabbit (consumers, herbivores). The grasshopper sends an arrow to a frog, the rabbit to a fox, the frog to a snake, and the snake and fox to an eagle (consumers). Dashed arrows lead from the plants and animals down to mushrooms and worms labeled decomposers, and a dashed arrow labeled 'nutrients return' leads back up to the grass. The arrows point from the eaten to the eater to show the direction energy moves. Labels and shapes, not color alone, carry the meaning so it prints clearly in grayscale.
A food-web diagram. At the top, a labeled Sun sends an arrow down to a grass plant labeled producer. The grass sends arrows to a grasshopper and a rabbit (consumers, herbivores). The grasshopper sends an arrow to a frog, the rabbit to a fox, the frog to a snake, and the snake and fox to an eagle (consumers). Dashed arrows lead from the plants and animals down to mushrooms and worms labeled decomposers, and a dashed arrow labeled 'nutrients return' leads back up to the grass. The arrows point from the eaten to the eater to show the direction energy moves. Labels and shapes, not color alone, carry the meaning so it prints clearly in grayscale.

Lesson 1 — Matter and Energy Move Through a Food Web

Summary

Learners follow matter and energy as they travel from the Sun into producers (plants and algae), through consumers (animals that eat), and back into the soil through decomposers. They learn the one rule every arrow in a food web follows — the arrow points from the eaten to the eater, because that is the direction the energy moves — and they build a small web of their own.

Objectives

  • Explain how matter and energy move through a food web, from producers to consumers and back through decomposers. (D06.S2.05.01)

Connection

Every time you eat, you are joining a food web. The rice in your bowl, the maize in a flatbread, the fish from a river, the greens from a garden — all of it got its energy the same way, by passing from a plant, through animals, to you. A coral reef in the Pacific, a savanna in East Africa, and a rice paddy in South Asia all run on the same rule: energy flows from what is eaten to what eats it. Today you learn to trace that flow.

Materials

  • Food web diagram
  • Arrow cards (or paper slips)
  • Blank web-builder page

Preparation

  • Print or draw the food web diagram and a blank web-builder page for each learner.
  • Cut arrow cards.
  • If using the yarn activity, have one ball of yarn ready.

Facilitator note

Written to the learner (“you”). The one rule to land is the arrow points from the eaten to the eater (the direction energy flows), not the reverse. This is the single most common mix-up in food webs, so model it, then have learners check every arrow aloud: “does energy flow from this one to that one?” Note the word “energy” is used in its everyday sense here (the usable fuel living things get from food); Grade 4 met energy moving from place to place, and Grade 6 will formalize it. The Sun’s role is evidence-based science; the idea that all living things share one flow is also a gentle environmental value we hold — name that distinction if it comes up. See docs/facilitation.md.

Procedure

  1. Gather (5 min). Recall from Grade 4: living and nonliving things in an ecosystem depend on each other. Ask: where does the energy in your last meal come from, all the way back?
  2. Meet the pieces (10 min). Look at the diagram. Find the three kinds of organisms: producers (plants and algae — they make their own food using the Sun’s light), consumers (animals — they eat other living things), and decomposers (mushrooms, worms, and tiny living things — they break down dead matter and return nutrients to the soil). Point to one of each.
  3. The arrow rule (10 min). Trace one chain: Sun → grass → grasshopper → frog → snake → eagle. Notice the arrow always points from the eaten to the eater, because that is the direction the energy moves. Say it aloud for one link: “the energy flows from the grass to the grasshopper, so the arrow points at the grasshopper.” Many chains crossing together make a food web.
  4. Build your own web (20 min). On your blank page, place a producer, a few consumers, and a decomposer. Draw arrows between them. Then check every single arrow with a partner: does energy flow from the eaten to the eater? Fix any arrow that points the wrong way. Add a “nutrients return” arrow from the decomposer back to the producer.
  5. Close (5 min). Every arrow you drew is a story about where energy goes. The Sun starts it, plants catch it, animals pass it along, and decomposers send the matter back to begin again.

Differentiation

  • Support: Provide a pre-drawn web with missing arrows; learners add only the arrowheads. Practice the arrow rule aloud on one chain first.
  • Extension: Add a second chain that crosses the first (a true web) and explain what it means when one animal has arrows from two different foods.

Assessment

  • Formative (observation): Does the learner point every arrow from eaten to eater, and name one producer, one consumer, and one decomposer?
  • Self-check: The learner asks, “If I follow any arrow backwards, do I find where that energy came from?”

Home connection

At your next meal, trace one food on your plate back through its food web — the plant or animal, what it ate, and where the Sun comes in. Tell someone the story of your food.

Resources