• Quick retrieval from earlier learning (Food webs and interdependence). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Woodland food web: grass is eaten by rabbits and mice. Seeds are eaten by mice. Rabbits are eaten by foxes. Mice are eaten by foxes and owls. Which animal is eaten by two different predators? (rabbits / owls / mice / foxes) → micePrompt: Look for an animal that both foxes and owls eat.
2. Rabbits and sheep both eat grass in the same field. This is an example of… (competition / predation / photosynthesis / decomposition) → competitionPrompt: They both want the same limited resource.
3. Food webs: which statement is NOT true? (Plants compete for light, water and minerals. / Removing one species can affect many others in a food web. / Animals often compete for food, water and space. / A food web contains only one food chain.) → A food web contains only one food chain.Prompt: Think about what happens when one population changes.

• Show a food web and ask what would happen if one animal disappeared.
• Share the objective: Biodiversity under pressure and how we protect it. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: A survey found 200 breeding pairs of a bird species in 2010 and 180 in 2024. What was the percentage decrease?
• Step 1: 200 − 180 = 20
• Step 2: 20 ÷ 200 × 100 = 10
• Step 3: So the answer is: 10 %
• Answer: 10 %
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. A survey found 120 hedgehogs counted in a survey in 2010 and 102 in 2024. What was the percentage decrease? → 15 %Prompt: Find the decrease first.
2. Why is high biodiversity good for an ecosystem? (It makes the ecosystem more stable because species depend on many others / It removes all predators / It stops the water cycle / It means fewer species compete) → It makes the ecosystem more stable because species depend on many othersPrompt: Think about what happens if one food source disappears.

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Biodiversity: which statement is NOT true? (Fertiliser running into lakes can cause algae to grow and oxygen to fall. / Human activity has no effect on extinction rates. / Breeding programmes can help protect endangered species. / Deforestation reduces biodiversity and adds carbon dioxide to the air.) → Human activity has no effect on extinction rates.Prompt: What does biodiversity actually measure?
2. A survey found 400 hectares of rainforest in 2010 and 320 in 2024. What was the percentage decrease? → 20 %Prompt: Find the decrease first.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-10.