Exam questions · Biology · Communities in Ecosystems
Levels of Organisation in an Ecosystem
- 6 exam questions
- 16 marks
- 8 quick checks
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1 Name [3 marks]
Figure 1 shows levels of organisation in a pond. Name the levels shown at A, B and C.
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Model answer
A is a population. B is a community. C is an ecosystem.
Mark scheme
- A: population — 1 mark
- B: community — 1 mark
- C: ecosystem — 1 mark
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2 State [2 marks]
State what is meant by a population and by a habitat.
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Model answer
A population is all the organisms of one species living in an area. A habitat is the place where an organism lives.
Mark scheme
- Population: all the organisms of one species in an area — 1 mark
- Habitat: the place where an organism lives — 1 mark
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3 Explain [2 marks]
Explain the difference between a community and an ecosystem.
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Model answer
A community is all the living things, the populations of all the different species, in an area. An ecosystem is the community together with the non-living, abiotic, parts of the environment.
Mark scheme
- A community is only the living things — 1 mark
- An ecosystem also includes the abiotic parts — 1 mark
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4 Describe [3 marks]
A woodland contains 40 oak trees, 300 bluebells, 25 foxes and thousands of beetles. Describe the populations and the community in the woodland.
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Model answer
The 40 oak trees are one population, and the bluebells, the foxes and the beetles are other populations, each made of one species. All the populations together form the woodland community.
Mark scheme
- Each species is a separate population — 1 mark
- Oak trees, bluebells, foxes and beetles named as populations — 1 mark
- All the populations together are the community — 1 mark
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5 Calculate [3 marks]
A student counts the animals in a rock pool community. There are 45 limpets, 15 crabs and 40 sea anemones. Calculate the percentage of the animals that are limpets, and the fraction that are crabs, in its simplest form.
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Model answer
Limpets are 45 per cent of the animals. Crabs are three twentieths of the animals (15 out of 100).
Mark scheme
- Total = 45 + 15 + 40 = 100 — 1 mark
- Limpets: 45 per cent — 1 mark
- Crabs: 15/100 = 3/20 — 1 mark
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6 Explain [3 marks]
A pond is polluted and the temperature of the water rises. Explain why this could affect the whole ecosystem.
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Model answer
The abiotic factors in the ecosystem have changed. Some species may not survive in the changed conditions, so their populations fall. The other species that feed on them, or compete with them, are affected, so the whole community can change.
Mark scheme
- Abiotic factors change — 1 mark
- Some populations fall or die — 1 mark
- Other populations are affected, so the community changes — 1 mark
Quick check
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1
What is a population?
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B: All the organisms of one species in an area
A population is all the organisms of one species in an area.
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2
Which level of organisation includes the abiotic factors?
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D: Ecosystem
An ecosystem is the community and its non-living surroundings.
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3
What is a community?
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A: All the populations in an area
A community is all the populations of different species living in an area.
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4
Which of these is a habitat?
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C: A pond
A habitat is the place where an organism lives, such as a pond.
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5
What is the smallest level of organisation?
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B: Organism
An organism is a single living thing.
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6
Which is an example of a community?
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D: All the plants and animals in a wood
A community is all the different species living in an area.
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7
In a pond, which of these is an abiotic part of the ecosystem?
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C: The temperature of the water
The temperature of the water is non-living.
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8
How many species are there in a population?
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A: One
A population is made of organisms of one species.