Explain how resource partitioning among species within the same guild reduces interspecific competition and promotes coexistence.

IB DP Biology Higher Level (2023 syllabus) — C4.1 Populations and communities · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Species in the same guild use the same broad type of resource, so they can compete for it.
Resource partitioning means the species divide the resource – for example, they may use different micro‑habitats, feed at different times, or take different sized prey.
By partitioning the resource the species’ niches overlap less, so the intensity of interspecific competition is lowered.
With reduced competition no species is competitively excluded, allowing several species to coexist and maintain diversity in the community.

Examiner tips

  • Use the word ‘guild’ and explain that it means similar resource use.
  • Show the sequence: same guild → potential competition → partitioning → less overlap → coexistence.
  • Include examples of partitioning (micro‑habitat, time, prey size).

Common mistakes

  • Confusing ‘guild’ with ‘species’ or ‘community’.
  • Omitting the link between reduced competition and coexistence.

Mark scheme (4 marks)

  1. Species in the same guild exploit the same broad category of resources, creating potential for interspecific competition.
  2. Resource partitioning occurs when species divide / differentiate use of available resources, for example by exploiting different microhabitats, feeding at different times, or taking different prey sizes.
  3. Partitioning reduces niche overlap, which lowers the intensity of interspecific competition between the co-occurring species.
  4. Because no single species is competitively excluded, multiple species can stably coexist, maintaining species diversity within the community.

Key terms in this question

guild · resource partitioning · interspecific competition · coexistence

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