Decomposers

The idea

Decomposers, microorganisms such as bacteria and fungi, break down dead remains and wastes, turning complex organic substances into simple inorganic substances that go into the soil and are used again by plants.

Fallen leaves

Dead leaves and the waste of animals fall on the ground. After some time they are gone, but the plants nearby keep growing.

What happens to the dead remains and wastes in an ecosystem?

• Microorganisms break them down and the plants use the products
• They stay on the ground unchanged
• The Sun turns them back into living leaves

What happens to the remains

Press Next step.

Back to the soil

Bacteria and fungi break down the dead remains and wastes. The complex organic substances become simple inorganic substances. These go into the soil and the plants use them once more.

Decomposers, microorganisms such as bacteria and fungi, break down dead remains and wastes, turning complex organic substances into simple inorganic substances that go into the soil and are used again by plants.

Notes

Decomposers break down dead remains into simple inorganic substances that plants use again.

Check yourself

Which organisms are the decomposers?

What do decomposers break down?

Decomposers turn complex organic substances into what?

What happens to the simple inorganic substances made by decomposers?

• Green plants that make food. Green plants that make food are producers.
• Microorganisms such as bacteria and fungi — correct. Yes!
• Animals that eat other animals. Animals that eat other animals are carnivores, which are consumers.
• Inorganic substances in the soil into complex organic substances. Decomposers do the opposite. They turn complex organic substances into simple inorganic substances.
• The leaves of living plants. Decomposers break down dead remains and waste products of organisms.
• The dead remains and waste products of organisms — correct. Yes!
• Simple inorganic substances — correct. Yes!
• Sugar and starch. Sugar and starch are made by producers, not by decomposers.
• More complex organic substances. Decomposers break complex substances down. They do not build them up.
• They are lost from the ecosystem. They go into the soil, and plants use them again.
• They go into the soil and are used once more by plants — correct. Yes!
• They are eaten by herbivores in place of grass. The book says that these substances go into the soil and are used up once more by plants.