Ecosystems — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A rabbit is a producer because it eats plants to get its energy.
Corrected: A rabbit is a consumer because it eats plants to get its energy.
The corrected sentence is: "A rabbit is a consumer because it eats plants to get its energy.". The original sentence "A rabbit is a producer because it eats plants to get its energy." contained an error that needed to be fixed.
2. Fix the sentence:
Decomposers like mushrooms hunt and eat living animals for nutrients.
Corrected: Decomposers like mushrooms break down dead matter and return nutrients to the soil.
The corrected sentence is: "Decomposers like mushrooms break down dead matter and return nutrients to the soil.". The original sentence "Decomposers like mushrooms hunt and eat living animals for nutrients." contained an error that needed to be fixed.
3. Fix the sentence:
The Sun is a biotic factor because it provides energy for all living things.
Corrected: The Sun is an abiotic factor because it is not alive even though it provides energy.
The corrected sentence is: "The Sun is an abiotic factor because it is not alive even though it provides energy.". The original sentence "The Sun is a biotic factor because it provides energy for all living things." contained an error that needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. Plants are called producers because they make their own food using sunlight.
Producers (autotrophs) make their own food via photosynthesis using sunlight, water, and CO₂.
2. Animals that eat other organisms for energy are called consumers.
Consumers (heterotrophs) cannot make their own food and must eat other organisms to get energy.
3. Fungi and bacteria are decomposers that break down dead plants and animals.
Decomposers break down dead organic matter and return nutrients to the soil for producers to use.
4. Producers use a process called photosynthesis to turn sunlight into food.
Photosynthesis: sunlight + water + CO₂ → glucose + oxygen. This is how plants make food.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. What would happen to an ecosystem if all the decomposers disappeared?
Sample answer: Dead plants and animals would pile up and nutrients would not return to the soil. Without those nutrients, producers like plants would struggle to grow, which would affect the entire food chain.
Decomposers recycle nutrients. Without them, nutrients get locked in dead matter and the cycle breaks.
2. Why are producers the most important part of an ecosystem?
Sample answer: Producers are the most important because they convert sunlight into food through photosynthesis. All other organisms in the ecosystem depend on producers either directly or indirectly for their energy.
Every food chain starts with a producer. Without them, no energy enters the ecosystem.