45-minute lesson
Primary 4 Science: Food chains in Australian habitats
Lesson objective
- Explain that a food chain shows how energy passes from one living thing to another when it is eaten.
- Identify producers and consumers in a food chain.
- Build food chains from habitats such as grasslands, ponds, forests and the ocean, and predict what happens if one link is removed.
Success criteria:
- I can draw a food chain with arrows pointing the right way.
- I can label the producer and the consumers in a food chain.
- I can predict what might happen if one living thing disappeared from a food chain.
Materials
- Small cards or sticky notes
- Pencils and coloured pencils
- A long strip of paper for drawing chains
- Books or pictures showing animals from grasslands, ponds, forests and the ocean
Introduction
5 minIntroduce today's words:
- food chain: A diagram that shows what eats what, with arrows showing how food energy passes along.
- producer: A living thing, usually a plant, that makes its own food using sunlight.
- consumer: A living thing that gets its energy by eating other living things.
- herbivore: An animal that eats only plants.
- carnivore: An animal that eats only other animals.
- decomposer: A living thing, such as a fungus, bacterium or worm, that breaks down dead plants and animals.
Ask your child what they already know about food chains in australian habitats.
Explanation
9 minEvery living thing needs energy to live and grow. A food chain shows how that energy passes from one living thing to the next when it is eaten.
Food chains begin with a producer. Plants are producers because they make their own food using sunlight, air and water. Almost all energy in a food chain first came from the Sun.
Animals are consumers. They cannot make their own food, so they eat other living things.
- A herbivore eats only plants, such as a grasshopper or a rabbit.
- A carnivore eats only animals, such as a snake or an owl.
- An omnivore eats plants and animals, such as many birds, bears and people.
The arrows in a food chain point from the thing being eaten to the thing that eats it. The arrow means 'is eaten by' and shows which way the energy goes. For example: grass → grasshopper → frog → snake.
Every habitat has its own food chains. In a pond: algae → water snail → fish → heron. In a forest: seeds → mouse → owl. In the ocean: tiny drifting algae → krill → whale.
Decomposers, such as fungi, bacteria and worms, break down dead plants and animals and return nutrients to the soil so producers can grow again.
Food chains are linked. If one living thing disappears, others are affected. If frogs disappeared, grasshoppers might increase because fewer are being eaten, and snakes would have less food.
Worked examples
7 minBuild a grassland chain
Put these in a food chain: snake, grass, frog, grasshopper.
Step 1: Find the producer (it makes its own food): grass.
Step 2: What eats grass? The grasshopper.
Step 3: What eats the grasshopper? The frog.
Step 4: What eats the frog? The snake.
Step 5: Draw arrows from the eaten to the eater.
Answer: grass → grasshopper → frog → snake
Label the chain
In seeds → mouse → owl, label the producer and the consumers.
Step 1: Seeds come from plants, which make their own food: producer.
Step 2: The mouse eats seeds: consumer (herbivore here).
Step 3: The owl eats the mouse: consumer (carnivore).
Answer: Producer: seeds (plant). Consumers: mouse and owl.
What if one link goes?
In grass → grasshopper → frog → snake, what might happen if a disease killed most of the frogs?
Step 1: Frogs eat grasshoppers, so fewer grasshoppers are eaten.
Step 2: Grasshopper numbers could rise, and they might eat more grass.
Step 3: Snakes eat frogs, so snakes have less food and may decrease or move away.
Answer: Grasshoppers would likely increase, grass could decrease and snakes would struggle to find food.
Guided practice (do together)
9 min1. In grass → grasshopper → frog → snake, which is the producer?
(a) Grasshopper (b) Frog (c) Snake (d) Grass
2. What does the arrow in a food chain mean?
(a) 'Is eaten by' (b) 'Is bigger than' (c) 'Lives next to' (d) 'Is faster than'
3. Where does almost all the energy in a food chain first come from?
(a) The soil (b) The Sun (c) Water (d) The snake
4. In grass → grasshopper → frog → snake, which animal is a herbivore?
(a) Frog (b) Snake (c) Grasshopper (d) None of them
Independent practice
11 min5. If most frogs disappeared from that chain, what would probably happen to the grasshoppers?
(a) They would increase (b) They would all disappear (c) They would turn into frogs (d) Nothing would change
6. An animal that eats both plants and animals is called an o________.
7. Living things that cannot make their own food and must eat other living things are called ____.
8. In seeds → mouse → owl, what does the owl eat?
Questions to check understanding
- Can you draw a food chain with arrows pointing the right way?
- Can you label the producer and the consumers in a food chain?
- Can you predict what might happen if one living thing disappeared from a food chain?
- What was the trickiest part today?
Answer guide
1. Grass — Grass makes its own food using sunlight, so it is the producer.
2. 'Is eaten by' — Arrows point from the food to the animal that eats it.
3. The Sun — Plants capture energy from sunlight to make food.
4. Grasshopper — The grasshopper eats only plants.
5. They would increase — With fewer frogs eating them, more grasshoppers would survive.
6. omnivore — Omnivores eat plants and animals.
7. consumers — Animals are consumers.
8. mouse — The arrow from mouse to owl shows the mouse is eaten by the owl.
Review
4 minRecap the success criteria together. Watch for these common misconceptions:
- Students often draw arrows the wrong way (from eater to eaten). Teach the arrow as 'is eaten by' or 'gives energy to'.
- Some students think plants get their food from the soil. Plants make their own food using sunlight, air and water; soil gives them water and small amounts of nutrients.
- Students may think removing a predator is always good for the animals it eats. Without predators, plant-eaters can grow in number and run out of food.
Extension activities
- Link several food chains from one habitat into a food web and see how many arrows you can draw.
- Watch a garden for 15 minutes and list producers and consumers you see.
- Start a small compost bucket and watch decomposers turn food scraps into soil over a few weeks.
Suggested follow-up
- Revisit food chains in australian habitats tomorrow with two or three quick questions from memory.
- Try the online practice check for this topic and look at any questions that need another go.
Tips for parents
- Ask your child to build a food chain for a meal: for example, grass → cow → person.
- Draw chains on cards so they can be rearranged and linked into a food web.
- Safety: if you look for minibeasts in the garden, look but do not touch spiders, wasps or snakes, and wash hands afterwards.