Food Webs and Energy — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A producer is an animal that eats plants to get energy from the sun.
Corrected: A producer is an organism, such as a plant, that makes its own food using energy from the sun.
The corrected sentence is: "A producer is an organism, such as a plant, that makes its own food using energy from the sun.". The original sentence "A producer is an animal that eats plants to get energy from the sun." contained an error that needed to be fixed.
2. Fix the sentence:
A food web shows a single straight path of energy from the sun to one animal.
Corrected: A food web shows many overlapping food chains and the multiple paths energy can take through an ecosystem.
The corrected sentence is: "A food web shows many overlapping food chains and the multiple paths energy can take through an ecosystem.". The original sentence "A food web shows a single straight path of energy from the sun to one animal." contained an error that needed to be fixed.
3. Fix the sentence:
Decomposers are predators that hunt and eat other animals for energy.
Corrected: Decomposers are organisms like fungi and bacteria that break down dead plants and animals, returning nutrients to the soil.
The corrected sentence is: "Decomposers are organisms like fungi and bacteria that break down dead plants and animals, returning nutrients to the soil.". The original sentence "Decomposers are predators that hunt and eat other animals for energy." contained an error that needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. Green plants are called producers because they make their own food.
Producers (plants, algae) use photosynthesis to make their own food from sunlight, water, and CO₂.
2. Animals that eat other animals are called predators.
Predators hunt and eat other animals (their prey). They are consumers at higher trophic levels.
3. All food chains begin with energy from the sun.
The sun is the ultimate energy source for almost all food webs. Plants capture solar energy through photosynthesis.
4. Mushrooms and bacteria are examples of decomposers.
Decomposers break down dead organic matter, recycling nutrients back into the soil for producers to use.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Explain the difference between a food chain and a food web.
Sample answer: A food chain shows one path of energy from a producer to consumers. A food web shows many food chains connected together because most animals eat more than one type of food.
Food chains are linear; food webs are interconnected networks showing the complexity of real ecosystems.
2. What would happen to a food web if all the producers disappeared?
Sample answer: The consumers that eat producers would run out of food and their populations would shrink. Then the predators that eat those consumers would also lose their food source. The whole web would collapse.
Producers are the base of all food webs. Without them, no energy enters the ecosystem and all consumer populations decline.