Unit 2: Ecosystems and Ecology
Topic 2.3: Habitat, Niche and Interactions Questions
Practice 20 exam-style questions for IB ESS Topic 2.3. 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 carrying capacity.
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Define the term limiting factor.
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Unlock Question3calculate5 marks
The graph shows population changes in snowshoe hares and lynx over a 16-year period.
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The graph shows changes in two populations (A and B) over time in an ecosystem.
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A lake has two fish species that both feed mainly on small zooplankton near the surface during the day. Suggest one change in resource use that could reduce competition between the fish.
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A grassland has abundant sunlight and space, but low rainfall. Suggest the most likely limiting factor for plant growth.
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A severe storm reduces a seabird population by 40 percent in one week. Explain why this is considered a density-independent factor.
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Distinguish between density-dependent and density-independent limiting factors.
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Distinguish between habitat and niche.
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Outline three components that could be used to describe the niche of a bird species.
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Figure 2 shows two different population growth patterns over a 50-year period.
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The graphs show predator–prey population changes in two different ecosystems (A and B).
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Outline what is meant by niche overlap and state one likely consequence for two species.
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Explain why ecosystems with a greater variety of niches often have higher biodiversity.
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Two insect-eating bird species live in the same woodland habitat. Explain how they could reduce competition and coexist.
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The graph shows prey (mice) and predator (owls) population changes from year 0 to year 8. The shaded area represents years 8–12.
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Outline three examples of limiting factors that could reduce the population size of deer in a forest.
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Explain why disease is often a density-dependent factor in animal populations.
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