Unit 3: Interaction and Interdependence
Topic 3.8: Populations and Communities Questions
Practice 20 exam-style questions for IB Biology Topic 3.8. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
1Identify1 mark
Why do ecologists usually estimate a population's size from a sample instead of counting every individual?
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State the sampling method used to estimate the population size of an animal that moves around its habitat.
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State the interspecific relationship in which both species are harmed.
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A keystone species in a community is present in only small numbers, yet its loss would change the whole community.
Which everyday comparison best captures this idea?
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An ecologist wants to estimate the size of a population of fast-moving beetles.
Which sampling method is most suitable?
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State the term for the process in which a plant releases a chemical that inhibits the growth of other plants nearby.
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What is meant by the carrying capacity of a habitat for a species?
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State whether competition between two species for the same food is an abiotic or a biotic factor.
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A plant releases a chemical into the soil that inhibits the growth of other plants nearby.
What is the name of this process?
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Which statement best describes an ecological niche?
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What does species richness measure in a community?
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An interaction between two species harms BOTH organisms.
Which interspecific relationship is this?
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Which term means all the individuals of one species living in the same area at the same time?
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Which of the following is an ABIOTIC factor that can affect where a species lives?
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State what is meant by ecological succession.
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State what is meant by the carrying capacity of a habitat for a population.
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Which term means the place (the type of environment) where a species or community normally lives?
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At the carrying capacity, what is true of the birth rate and death rate of the population?
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Which sampling method is most suitable for estimating the number of dandelion plants in a meadow?
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Which interspecific relationship benefits BOTH species?
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