Rocket builds a model on the workbench. A paper leaf, a toy rabbit, a toy hawk and a pile of brown crumbs for soil.
"Energy comes from the Sun," he says. "But the stuff, the matter, where does it start?"
Raven moves the crumbs back under the paper leaf. "What do you notice if the soil feeds the next plant?" she asks.
Nova traces a glowing circle around the whole model. "Interesting," she says. "Does this path have an end?"
"No!" Rocket says. "It goes in a circle!"
Matter cycles between the air and soil and among plants, animals and microbes. Microbes are tiny living things like bacteria.
Plants take in carbon dioxide and water. They build them into food.
Animals eat plants, or eat animals that ate plants. Animals release waste and carbon dioxide back into the environment.
When plants and animals die, decomposers break them down. Materials go back to the air and soil, ready for new plants.
Energy comes in from the Sun and flows through a food web.
Matter is different. It goes around and around.
The same materials move from air and soil, to living things, and back again.
| Statement | True or false? |
|---|---|
| Matter cycles between air, soil and living things. | ? |
| Microbes are tiny living things like bacteria. | ? |
| Animals never release anything back into the environment. | ? |
| Decomposers return materials to the air and soil. | ? |
You discovered a circle that has been turning for a very long time. Tomorrow we will see it in real forests.