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Science lesson plan · 5th grade (Year 6 in England) · 45 minutes

Predict what happens when a food web changes

Ecosystems and food chains

CCSS NGSS.5-LS2-1England: KS2 Y6 Living things and their habitatsEngland: KS3 Biology: Interactions and interdependencies

Objective and success criteria

Students will: Predict what happens when a food web changes.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Read a food web: who eats whom?

Leads to: the next skill in this area.

Materials: Food web cards, Arrows to build chains, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Read a food web: who eats whom?). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Here is a pond food web. (An arrow points from the food to the animal that eats it.) algae → mayfly larva algae → tadpole pondweed → pond snail algae → pond snail mayfly larva → dragonfly larva tadpole → dragonfly larva mayfly larva → stickleback (small fish) dragonfly larva → stickleback (small fish) stickleback (small fish) → heron tadpole → heron Which of these does the dragonfly larva eat? (heron / pond snail / pondweed / mayfly larva) → mayfly larvaPrompt: Find the arrows that point TO this animal.
  2. Here is an ocean food web. (An arrow points from the food to the animal that eats it.) phytoplankton → zooplankton kelp (seaweed) → sea urchin zooplankton → herring sea urchin → sea otter herring → seal seal → orca herring → orca Which of these is a producer? (kelp (seaweed) / sea otter / herring / orca) → kelp (seaweed)Prompt: Producers make their own food from sunlight.
  3. Here is an ocean food web. (An arrow points from the food to the animal that eats it.) phytoplankton → zooplankton kelp (seaweed) → sea urchin zooplankton → herring sea urchin → sea otter herring → seal seal → orca herring → orca A disease kills most of the seal. Which animal loses one of its foods? (orca / sea otter / herring / sea urchin) → orcaPrompt: Which animals have an arrow coming from it?

Hook · 5 min

  • Show a food web and ask what would happen if one animal disappeared.
  • Share the objective: Predict what happens when a food web changes. Read the success criteria together.

I do: model it · 10 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Sea otters eat sea urchins, and sea urchins eat kelp. Hunters remove most otters. What happens to the kelp forest?
  • Step 1: With fewer predators, urchin numbers rise and they overgraze the kelp.
  • Step 2: So the answer is: Urchins increase and eat much of the kelp.
  • Answer: Urchins increase and eat much of the kelp.
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 10 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. In a meadow, rabbits are eaten by foxes. A disease kills many rabbits. What will probably happen to the foxes? (They will struggle to find food and their numbers may fall. / They will start eating grass. / Their numbers will rise quickly. / They will grow bigger.) → They will struggle to find food and their numbers may fall.Prompt: What happens to predators when prey is scarce?
  2. True or false? Animals that eat many foods cope better when one food runs out. (True / False) → TruePrompt: Follow the arrows to see who depends on whom.

You do: independent practice · 10 min

  • Students work on the student sheet. Circulate and check the first two answers of every student early.
  • Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

Exit ticket · 5 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. What is a likely knock-on effect: a pesticide kills most of the insects in a field? (reef fish lose food and shelter / birds that eat small fish have less food / rabbit numbers rise and more grass is eaten / insect-eating birds have less food) → insect-eating birds have less foodPrompt: Who eats what was lost or added?
  2. Sea otters eat sea urchins, and sea urchins eat kelp. Hunters remove most otters. What happens to the kelp forest? (Urchins increase and eat much of the kelp. / The urchins disappear. / The kelp grows faster. / Nothing changes.) → Urchins increase and eat much of the kelp.Prompt: Follow the chain: fewer otters → ? urchins → ? kelp.

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Read a food web: who eats whom?.
  • Use concrete materials: food web cards.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-5.

Free lesson plan from eurekami.com/lesson-plan-builder

eurekami

Predict what happens when a food web changes

Name

Date

Score/ 8

  1. Question 1

    True or false? Removing a predator can cause its prey to increase.

    • A. True
    • B. False

  2. Question 2

    Why is a food web with many links more stable than a single food chain?

    • A. Webs have fewer animals.
    • B. Chains are always longer.
    • C. If one food runs short, animals can eat something else.
    • D. Webs need no producers.

  3. Question 3

    What is a likely knock-on effect: a new fish is added to a lake and eats the small fish?

    • A. insect-eating birds have less food
    • B. rabbit numbers rise and more grass is eaten
    • C. birds that eat small fish have less food
    • D. reef fish lose food and shelter

  4. Question 4

    True or false? Animals that eat many foods cope better when one food runs out.

    • A. True
    • B. False

  5. Question 5

    Sea otters eat sea urchins, and sea urchins eat kelp. Hunters remove most otters. What happens to the kelp forest?

    • A. Urchins increase and eat much of the kelp.
    • B. The kelp grows faster.
    • C. Nothing changes.
    • D. The urchins disappear.

  6. Question 6

    What is a likely knock-on effect: a pesticide kills most of the insects in a field?

    • A. birds that eat small fish have less food
    • B. rabbit numbers rise and more grass is eaten
    • C. reef fish lose food and shelter
    • D. insect-eating birds have less food

  7. Question 7

    True or false? More predators always means more prey.

    • A. True
    • B. False

  8. Question 8

    What is a likely knock-on effect: foxes are removed from an island?

    • A. birds that eat small fish have less food
    • B. insect-eating birds have less food
    • C. rabbit numbers rise and more grass is eaten
    • D. reef fish lose food and shelter

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Answer key: Predict what happens when a food web changes

  1. 1. A. True

  2. 2. C. If one food runs short, animals can eat something else.

  3. 3. C. birds that eat small fish have less food

  4. 4. A. True

  5. 5. A. Urchins increase and eat much of the kelp.

  6. 6. D. insect-eating birds have less food

  7. 7. B. False

  8. 8. C. rabbit numbers rise and more grass is eaten