Unit 2: Ecosystems and Ecology
Topic 2.2: Communities and Ecosystems Questions
Practice 20 exam-style questions for IB ESS Topic 2.2. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
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Define the term ecosystem in environmental systems and societies.
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Define the term open system.
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Define the term ecosystem and distinguish between biotic and abiotic components, giving examples of each.
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Define the term sustainability in the context of environmental systems.
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Define the term resilience in the context of environmental systems.
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State one characteristic of a keystone species in an ecosystem.
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Define the term community in environmental systems and societies.
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Suggest two features of a desert habitat that help a cactus survive.
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Explain how a top predator can act as a keystone species in a food web.
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Outline two examples of matter entering or leaving a forest ecosystem that show it is an open system.
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What is the difference between a community and an ecosystem?
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Figure 3(a) shows a simplified food web in a seagrass meadow ecosystem.
Outline why green sea turtles may be described as a keystone species in seagrass ecosystems. [1 mark]
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Figure 3(a) shows a simplified food web in a seagrass meadow ecosystem.
Explain how a reduction in dugong numbers might lead to changes in the seagrass meadow food web. [3 marks]
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Figure 3(b) shows carbon stored in seagrass in ecosystems with and without green sea turtles.
Calculate the difference between carbon stored in seagrass in the ecosystem with and without green sea turtles.
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Figure 3(b) compares seagrass meadow ecosystems with and without green sea turtles.
Explain how green sea turtles may affect the stability of the seagrass meadow ecosystem. [3 marks]
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Figure 3(a) shows a simplified food web in a seagrass meadow ecosystem.
Using Figure 3(a), identify two organisms whose population would likely decline if tiger sharks were removed from the ecosystem. [2 marks]
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Outline what is meant by a trophic cascade.
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