Ecosystems and Food Webs Quiz

Grade 6 · Science · Quiz

Test your understanding of ecosystems, food webs, and energy flow.

Questions

1. Which of the following best describes a food web?

   1. A single path from producer to top predator
   2. Multiple overlapping food chains in an ecosystem
   3. A diagram of an animal's habitat
   4. A chart showing population sizes
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   Answer: Multiple overlapping food chains in an ecosystem

   Food webs show the real complexity of feeding relationships, unlike a simple linear food chain.

2. Herbivores are primary consumers because they eat producers directly.

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   Answer: True

   Herbivores eat plants (producers), making them the first consumers in the energy chain.

3. What role do decomposers play in an ecosystem?

   1. They produce energy from sunlight
   2. They hunt and eat other animals
   3. They break down dead organisms and recycle nutrients
   4. They convert water into oxygen
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   Answer: They break down dead organisms and recycle nutrients

   Decomposers are essential recyclers — they return carbon, nitrogen, and other nutrients to the ecosystem.

4. The variety of species in an ecosystem is called ___.

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   Answer: biodiversity

   Biodiversity is the measure of the number and variety of species in an area. High biodiversity = healthy ecosystem.

5. If all the plants in an ecosystem died, what would happen first?

   1. Decomposers would disappear
   2. Herbivore populations would decline
   3. Carnivores would increase
   4. Sunlight would decrease
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   Answer: Herbivore populations would decline

   Without plants (producers), herbivores lose their food source and their populations crash first.

6. Omnivores eat only plants.

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   Answer: False

   Omnivores eat both plants AND animals. Bears, humans, and raccoons are examples.

7. Which correctly lists the levels of a food chain from bottom to top?

   1. Consumer → Producer → Decomposer
   2. Producer → Primary Consumer → Secondary Consumer
   3. Decomposer → Consumer → Producer
   4. Secondary Consumer → Primary Consumer → Producer
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   Answer: Producer → Primary Consumer → Secondary Consumer

   Energy always flows upward from producers through successive levels of consumers.

8. In the 10% rule, only ___ percent of energy passes from one trophic level to the next.

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   Answer: 10

   The 10% rule means energy transfer is very inefficient — 90% is lost as heat at each step.

9. An eagle eats a snake that ate a frog that ate a grasshopper that ate grass. The eagle is a:

   1. Primary consumer
   2. Secondary consumer
   3. Tertiary consumer
   4. Quaternary consumer
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   Answer: Quaternary consumer

   Grass→grasshopper (primary)→frog (secondary)→snake (tertiary)→eagle (quaternary consumer).

10. A trophic cascade occurs when removing one species affects many others in an ecosystem.

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    Answer: True

    When a keystone species is removed, the effects ripple through the entire food web — this is a trophic cascade.

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