Unit 2: Ecosystems and Ecology
Topic 2.4: Food Chains & Webs and Trophic Levels Questions
Practice 20 exam-style questions for IB ESS Topic 2.4. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
1define1 mark
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Define the term trophic level.
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State the trophic level of a rabbit in the food chain grass → rabbit → fox.
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In the food chain oak leaves → caterpillar → robin → sparrowhawk, identify the secondary consumer.
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In the food chain phytoplankton → zooplankton → small fish → tuna, identify the secondary consumer.
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Compare and contrast food chains and food webs. Explain why food webs provide a more accurate representation of feeding relationships in ecosystems.
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Explain the role of decomposers in ecosystems and describe what would happen if all decomposers were removed from an ecosystem.
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Explain what the arrows represent in a food chain.
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Outline the role of producers in ecosystems.
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Describe the roles of producers, consumers, and decomposers in an ecosystem.
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Figure 1 shows a grassland food chain (DDT): Hawk → Snake → Frog → Grasshopper → Grass. Using Figure 1, identify the producer in this food chain.
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Figure 2 shows a marine food chain (mercury): Shark → Tuna → Mackerel → Shrimp → Phytoplankton. Identify the primary consumer in this food chain.
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Figure 1 shows a grassland food chain (DDT): Hawk → Snake → Frog → Grasshopper → Grass. State the trophic level of the frog.
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Figure 2 shows a marine food chain (mercury): Shark → Tuna → Mackerel → Shrimp → Phytoplankton. State the trophic level of the mackerel.
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Outline one strength and one weakness of using a food chain to model energy flow in an ecosystem.
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Distinguish between detritivores and saprotrophs.
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Figure 3(a) shows a simplified food web in a seagrass meadow ecosystem.
State the trophic level of sea cucumbers in the seagrass meadow ecosystem shown in Figure 3(a).
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A woodland has many scavengers, detritivores, and saprotrophs. Suggest one reason this could increase soil fertility.
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Explain why food webs are a more realistic model than food chains.
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Outline one way that greater connectivity in a food web can increase ecosystem resilience.
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