Food Webs and Energy Transfer Quiz

Grade 5 · Science · Quiz

Test your knowledge of how energy moves through ecosystems via food chains, food webs, and trophic levels.

Questions

1. A grasshopper eats grass, a frog eats the grasshopper, and a snake eats the frog. What is the frog's role?

   1. Producer
   2. Primary consumer
   3. Secondary consumer
   4. Decomposer
   Show answer

   Answer: Secondary consumer

   The frog eats the grasshopper (a primary consumer that eats grass), making the frog a secondary consumer — it is two steps away from the producer.

2. Where does the energy in almost all food chains ultimately come from?

   1. Soil nutrients
   2. The moon's gravity
   3. The sun
   4. Decomposers in the ground
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   Answer: The sun

   The sun is the original energy source for almost all food chains on Earth. Producers capture solar energy through photosynthesis and store it as chemical energy.

3. According to the 10% rule, if grass stores 10,000 calories of energy, how much energy is available to the rabbits that eat the grass?

   1. 10,000 calories
   2. 5,000 calories
   3. 1,000 calories
   4. 100 calories
   Show answer

   Answer: 1,000 calories

   The 10% rule states that only 10% of energy passes from one level to the next. 10% of 10,000 calories = 1,000 calories available to rabbits.

4. Decomposers are harmful to ecosystems because they destroy organisms.

   Show answer

   Answer: False

   Decomposers are essential to ecosystems. They break down dead organisms and waste, recycling nutrients back into the soil that plants need to grow.

5. If a disease wiped out all the rabbits in a food web (grass → rabbit → hawk), what would most likely happen?

   1. The hawk population would grow larger
   2. The grass would decrease and the hawk population would decline
   3. The grass would decline and the hawk population would grow
   4. Nothing would change
   Show answer

   Answer: The grass would decrease and the hawk population would decline

   Without rabbits, the hawk would lose its food source and its population would decline. With fewer rabbits eating it, grass would initially increase, but the ecosystem balance would be disrupted.

6. Which term describes an animal that only eats plants?

   1. Carnivore
   2. Omnivore
   3. Herbivore
   4. Decomposer
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   Answer: Herbivore

   Herbivores eat only plants (producers), making them primary consumers. Carnivores eat animals, and omnivores eat both plants and animals.

7. A diagram that shows energy decreasing at each higher level of a food chain is called an energy ________.

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   Answer: pyramid

   An energy pyramid visually represents how energy decreases at each higher trophic level, with the widest base representing producers and the smallest top representing apex predators.

8. Which group of organisms recycles dead matter and returns nutrients to the soil?

   1. Primary consumers
   2. Top predators
   3. Producers
   4. Decomposers
   Show answer

   Answer: Decomposers

   Decomposers (bacteria and fungi) break down dead organisms and animal waste, releasing nutrients like nitrogen and phosphorus back into the soil for producers to absorb.

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