Food Chain Builder

Little levels (ages 4 to 6)

1. Who eats what? Tap sun, grass, rabbit and fox in order to build the chain.
2. The pond chain Drag algae, little fish, big fish and heron into the right order.
3. Plant or animal? Sort living things that make their own food from the ones that have to eat.
4. Who is missing? Fill the gap in a chain with the right creature.
5. The forest chain A five-link chain from the sun to an owl.

Big levels (ages 7 to 9)

1. Take away the fox Predict what happens to the rabbits, then watch six seasons.
2. No grass A dry summer kills the grass; predict what happens to the foxes.
3. The food web Draw seven arrows between seven creatures.
4. The clean-up crew Sort out the worms, mushrooms and beetles that turn dead things into soil.
5. Plants, meat, or both? Sort nine animals by what they eat.
6. The energy pyramid Stack 1000 grass plants, 100 grasshoppers, 10 birds and 1 hawk.

The big ideas

• Every food chain starts with the sun. Plants capture sunlight and make their own food. Everything else eats plants, or eats something that ate plants. Scientists call plants producers and animals consumers.

• The arrows show where energy goes. An arrow points from the food to the eater: grass to rabbit, rabbit to fox. Reading the arrows tells you who depends on whom.

• Break a link and the whole chain feels it. Without foxes, rabbits boom, strip the grass, then starve. Without grass, rabbits dwindle and the foxes that never touched a blade of grass go hungry too.

• Real life is a web, not a chain. Most animals eat several things and are eaten by several others, which is what makes ecosystems tough but not unbreakable.

• Decomposers close the loop. Worms, fungi and beetles break dead plants and animals down into soil, and plants grow from that soil. Energy flows one way, but the materials go round.

• Energy is lost at every step. Only about a tenth of the energy in grass ends up in the grasshopper that eats it, which is why a meadow needs a thousand plants to support a single hawk.

Try it at home

1. Dinner chain At a meal, trace each food back to the sun: bread came from wheat that grew in sunlight; cheese came from a cow that ate grass.
2. Garden detectives Look under a log or a stone and find the clean-up crew: worms, woodlice, beetles. Put the log back gently.
3. Who eats what? Pick a local animal and find out what it eats and what eats it. Draw the chain with arrows pointing toward the eater.
4. Pyramid of snacks Use 10 raisins, 3 crackers and 1 cookie to build an energy pyramid, and talk about why there is only one cookie.

Ask after playing

• Why does every food chain start with the sun?
• What happened to the rabbits when the foxes went away?
• Why are there so many grass plants and so few hawks?