Unit 2: Ecosystems and Ecology
Topic 2.1: Species, Populations Questions
Practice 20 exam-style questions for IB ESS Topic 2.1. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
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List four abiotic factors that can affect the distribution of organisms in an ecosystem.
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Define the term population.
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Define the term dichotomous key.
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Outline the steps involved in using a dichotomous key to identify an organism.
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State two advantages of using dichotomous keys for organism identification.
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Distinguish between an organism and a species.
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State four observable physical features that could be used to identify plant species in the field.
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State the rules for writing a binomial name and provide an example.
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Distinguish between a population and a species, using wolves as an example.
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Distinguish between abiotic and biotic factors, giving one example of each.
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Outline why classification systems may change over time.
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Outline three limitations of using dichotomous keys for identifying organisms.
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Explain why accurate identification of organisms is important for conservation efforts.
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Figure 3 shows a tolerance curve for a species of freshwater fish, illustrating how population growth rate changes with water temperature.
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Figure 2 shows three types of population distribution patterns that can be observed in nature.
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What is the main purpose of scientific classification in biology?
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Which of the following is an abiotic factor in an ecosystem?
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