Questions on Trophic Levels
Multiple-Choice Questions: Trophic Levels
1. What does a trophic level represent in an ecosystem?
A) The rate of reproduction of species
B) The role of organisms in water purification
C) The position an organism occupies in a food chain
D) The type of habitat an organism prefers
E) The lifespan of an organism
2. Which organisms are found at the first trophic level?
A) Herbivores
B) Carnivores
C) Decomposers
D) Omnivores
E) Producers
3. What is the typical energy transfer efficiency from one trophic level to the next?
A) 90%
B) 50%
C) 25%
D) 10%
E) 1%
4. What kind of organisms are usually at the second trophic level?
A) Producers
B) Secondary consumers
C) Primary consumers
D) Decomposers
E) Omnivores
5. A hawk that eats a snake, which ate a mouse, which ate seeds, is at what trophic level?
A) First
B) Second
C) Third
D) Fourth
E) Fifth
6. Why are there usually only 4–5 trophic levels in a food chain?
A) Organisms refuse to eat others
B) Energy is lost at each level
C) Ecosystems are too simple
D) Decomposers stop the chain
E) Organisms grow smaller
7. Which of the following is a primary consumer?
A) Grass
B) Cow
C) Wolf
D) Fungus
E) Lion
8. Which of the following organisms is at a higher trophic level than an insect?
A) Grass
B) Bird that eats insects
C) Bacteria that decompose insects
D) Other insects
E) Fern
9. Which organism is a secondary consumer in the following chain: grass → grasshopper → frog → snake?
A) Grass
B) Grasshopper
C) Frog
D) Snake
E) Decomposer
10. Which of these organisms is at the top trophic level in most ecosystems?
A) Decomposer
B) Primary consumer
C) Producer
D) Apex predator
E) Detritivore
11. What determines an organism’s trophic level?
A) Its reproductive rate
B) Its size
C) What it eats and what eats it
D) Its lifespan
E) Its speed
12. Which of these organisms occupies more than one trophic level?
A) Algae
B) Cow
C) Omnivorous bear
D) Fungus
E) Mushroom
13. Which of the following is NOT considered when defining a trophic level?
A) Source of energy
B) Feeding behavior
C) Habitat size
D) Position in food chain
E) Role as producer or consumer
14. Which trophic level typically has the greatest biomass?
A) Primary consumers
B) Tertiary consumers
C) Producers
D) Secondary consumers
E) Decomposers
15. What type of energy is passed from one trophic level to another?
A) Heat energy
B) Sound energy
C) Chemical energy
D) Mechanical energy
E) Solar energy
16. A decomposer is best described as:
A) First trophic level
B) Not assigned a specific level but essential to all
C) Third trophic level
D) Fourth trophic level
E) Second trophic level
17. In a marine food chain, phytoplankton belong to which trophic level?
A) First
B) Second
C) Third
D) Fourth
E) Fifth
18. A trophic pyramid narrows at the top because:
A) Organisms get smaller
B) More sunlight is available at the bottom
C) Energy decreases at each level
D) Oxygen is limited
E) Water becomes scarce
19. What limits the number of trophic levels an ecosystem can support?
A) Biomass of consumers
B) The number of herbivores
C) Availability of sunlight
D) Energy loss at each level
E) Amount of space
20. Which of the following correctly orders the trophic levels from bottom to top?
A) Producer → Tertiary consumer → Secondary consumer → Primary consumer
B) Producer → Primary consumer → Secondary consumer → Tertiary consumer
C) Tertiary consumer → Producer → Primary consumer → Secondary consumer
D) Primary consumer → Producer → Secondary consumer → Decomposer
E) Decomposer → Producer → Consumer → Predator
Answer Key with Explanations
1. C – A trophic level indicates an organism's position in a food chain in terms of feeding and energy transfer.
2. E – Producers (like plants and algae) make up the first trophic level.
3. D – About 10% of energy is transferred to the next trophic level, the rest is lost as heat.
4. C – Primary consumers (usually herbivores) make up the second trophic level.
5. D – The hawk is at the fourth trophic level: seeds (1) → mouse (2) → snake (3) → hawk (4).
6. B – Energy decreases at each trophic level, limiting the number of sustainable levels.
7. B – A cow eats grass (a producer), so it is a primary consumer.
8. B – A bird that eats insects is at a higher trophic level than the insect.
9. C – The frog eats the grasshopper (primary consumer), so it's a secondary consumer.
10. D – Apex predators, such as hawks or lions, are usually at the top trophic level.
11. C – Trophic level is defined by what an organism eats and what eats it.
12. C – An omnivorous bear can act as both primary and secondary consumer.
13. C – Habitat size does not determine trophic level.
14. C – Producers have the greatest biomass as they are the foundation of energy flow.
15. C – Energy is transferred as chemical energy stored in organic molecules.
16. B – Decomposers recycle nutrients and don't fit neatly into one trophic level.
17. A – Phytoplankton are producers and belong to the first trophic level.
18. C – Energy is lost as heat at each level, so less is available higher up.
19. D – Energy loss at each trophic level limits how many levels ecosystems can sustain.
20. B – This is the correct order from base to top: Producer → Primary → Secondary → Tertiary.
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