Describe a community
A community is all the populations of different species in an ecosystem.
Section 19.4 · Populations
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Know population, community and ecosystem terms and read the axis labels on a graph.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What does a community contain?
What you will learn
- Define a community in terms of populations and species
- Distinguish a community from one population
Combine populations of different species
A community consists of all the populations of different species in an ecosystem. It includes interacting populations of plants, animals and microorganisms that live in the specified place. Each population within the community is a group of one species in an area at a time.
The term community focuses on living populations. It does not include the non-living environment in its definition; that wider interacting unit is an ecosystem. When using a habitat example, identify more than one species and keep the same ecosystem boundary.
Read the nested scale
A species population is one part of a community. A community contains the different populations. The ecosystem includes the community and its environment interacting together. These terms describe different levels of organisation, not different names for the same group.
If a question asks for a community, do not list only one species or add soil, water and light as community populations. Those non-living components belong to the ecosystem description.
Pause and explain
A forest description lists trees, birds, fungi and insects but excludes the soil and climate. What is the best term for the living groups?
Worked example
A pond contains populations of algae, snails, insects, fish and bacteria. What term describes all these living populations together?
Show the worked solution
- Each named organism group represents a population.
- The combined populations are of different species.
Answer Together, the populations of different species form the pond community.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A garden contains populations of grass, ants, earthworms and birds. Name the group formed by all these populations and explain.
Give me a hint
Look for different species living in the same ecosystem.
Compare my reasoning
- The groups are populations of different species.
- Together these living populations are a community.
They form the garden community because a community includes the populations of different species in an ecosystem.
Look for these in your work
- Different populations identified
- Definition applied
A student defines a community as “all organisms and the temperature in a pond.” Correct the definition and name the wider unit.
Give me a hint
Separate living populations from the environment.
Compare my reasoning
- A community is all populations of different species.
- The organisms and environment interacting form an ecosystem.
A community is all the populations of different species. The interacting community and its environment together form the ecosystem.
Look for these in your work
- Community corrected
- Ecosystem distinguished
A survey records only one species of reed in a wetland. Does that record alone identify the full community? Explain.
Give me a hint
A community includes all different species, not one recorded population.
Compare my reasoning
- The reed count is one population.
- More species populations must be included for the community.
No. It describes a reed population only; the full community includes all populations of different species in the wetland ecosystem.
Look for these in your work
- Single population classified
- Scope limitation stated
Common mistakes
- Calling the non-living environment part of the community
- Defining a community as one species
- Confusing a community with an ecosystem
What can you explain now?
What does a community contain?
Compare with the explanation
All populations of different species in an ecosystem
The community is the living populations together.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Define community and explain how it differs from a population.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.