Which list shows the levels of organisation in an ecosystem from smallest to largest?
- Organism, population, community, ecosystem
- Population, organism, community, ecosystem
- Organism, community, population, ecosystem
- Ecosystem, community, population, organism
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Answer: A A (1)
Bluebells grow on the floor of a woodland under tall oak trees. Suggest two factors that the bluebells and the oak trees compete for.
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- any two from:
- light (1)
- water (1)
- mineral ions (1) allow nutrients from the soil
- space (1)
- Max 2
The table shows the number of plants of one species per m² in soils of different pH. (a) State the soil pH at which the plant is most abundant. (1) (b) Describe how the number of plants changes as the soil pH increases. (2)
| Soil pH | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|
| Number of plants per m² | 2 | 14 | 40 | 38 | 9 |
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- (a) pH 6 (1)
- (b) number increases from pH 4 to pH 6 (1)
- then decreases from pH 6 to pH 8 (1)
- allow correct data quotes, for example rises from 2 to 40 plants per m², in place of one (b) mark
A lake contains small fish that feed on insect larvae. A new predatory fish species arrives in the lake. It eats only the small fish. (a) Explain how this could affect the population of small fish. (2) (b) Explain how this could affect the population of insect larvae. (2)
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- (a) small fish are eaten / preyed on (1)
- so their numbers decrease (1)
- (b) fewer small fish to eat the larvae (1)
- so the numbers of larvae increase (1)
Polar bears live in the Arctic. (a) A polar bear has a thick layer of fat under its skin. Suggest how this is an adaptation to its environment. (1) (b) A polar bear has white fur. Suggest how this is an adaptation. (1) (c) Bacteria that live in deep sea vents are adapted to very extreme conditions. Name the term for organisms like this. (1)
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- (a) insulation / reduces heat loss in the cold (1)
- (b) camouflage in the snow, so it can get close to its prey without being seen (1) allow to hide from prey
- (c) extremophiles (1)