Energy in Ecosystems — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Organisms that break down dead plants and animals are called decomposers.
Decomposers break apart dead matter so the nutrients can return to the soil.
2. Mushrooms and molds are examples of decomposers called fungi.
Fungi release chemicals that break down dead material into smaller nutrients.
3. Tiny one-celled decomposers found in soil are bacteria.
Bacteria help recycle nitrogen and other nutrients back into the soil.
4. Decomposers return important nutrients to the soil for plants to use.
Recycled nutrients let producers grow, which keeps the ecosystem energy cycle going.
5. Without decomposers, dead plants and animals would simply pile up.
Decomposers prevent buildup of dead matter and keep ecosystems healthy.
6. Decomposers are an important part of every ecosystem.
Every ecosystem needs decomposers to recycle matter and support new life.
7. The breakdown of dead matter into nutrients is called decomposition.
Decomposition releases stored nutrients so producers can use them again.
8. Earthworms help decomposition by breaking dead leaves into smaller pieces.
Worms speed up decomposition by mixing soil and shredding dead material.
9. Decomposers are sometimes called nature's recyclers.
Decomposers recycle the matter in dead organisms back into the ecosystem.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Decomposer
→ Organism that breaks down dead matter
Organism that breaks down dead matter
Fungi
→ Mushrooms and molds that recycle nutrients
Mushrooms and molds that recycle nutrients
Bacteria
→ Tiny one-celled organisms in the soil
Tiny one-celled organisms in the soil
Decomposition
→ The process of breaking down dead matter
The process of breaking down dead matter
Knowing these decomposer words helps Grade 5 students explain how matter cycles in ecosystems.