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DSE Biology: Applied Ecology (Elective) — Practice Questions & Answers
How populations and communities are studied, how pollution affects ecosystems and can be controlled, and how conservation supports sustainable use of natural resources.
384 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Medium
After farmland is abandoned, the natural process by which the area is gradually recolonised and the community changes over time is:
ecological succession
eutrophication
biological control
artificial selection
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Why This directional change in community is ecological succession.
2
Multiple choice · Easy
The earliest plants to colonise abandoned bare ground are described as:
pioneer species
climax species
keystone species
invasive predators
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Why Pioneer species are the first colonisers.
3
Multiple choice · Hard
During succession on abandoned land, the soil generally becomes:
deeper and richer in organic matter, supporting larger plants
progressively more infertile until no plants grow
completely waterlogged and anaerobic
unable to support any microorganisms
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Why Accumulating organic matter deepens and enriches the soil, supporting larger plants.
4
Fill in the blank · Medium
The orderly change in community composition over time on abandoned land is called
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Answer:
succession / ecological succession
Why Ecological succession restores natural vegetation.
5
Fill in the blank · Easy
The first organisms to colonise a bare area are the
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Answer:
pioneer
Why Pioneer species begin the succession.
6
Fill in the blank · Hard
Succession on land that still has soil, such as abandoned farmland, is
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Answer:
secondary
Why Secondary succession proceeds on disturbed but soil-bearing land.
7
Multiple choice · Medium
In shifting agriculture, clearing trees from a hill slope increases the annual runoff mainly because:
there is less vegetation to intercept rain and hold the soil
the soil becomes more fertile
transpiration increases
the slope becomes flatter
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Why Less vegetation means less interception of rain and less binding of soil.
8
Multiple choice · Hard
Which pair of agricultural activities would most increase surface runoff on cleared land?
removing ground vegetation and ploughing or loosening the topsoil
planting cover crops and terracing
adding mulch and reforesting
reducing irrigation and resting the land
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Why Removing ground cover and loosening topsoil both raise runoff.
9
Multiple choice · Easy
Soil erosion on deforested slopes is reduced by:
replanting vegetation whose roots bind the soil
removing all remaining plants
increasing the slope steepness
compacting the soil with heavy machinery
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Why Replanting vegetation binds the soil and lowers runoff.
10
Fill in the blank · Easy
Removing trees from a slope increases the surface
Check answer
Answer:
runoff / run-off / run off
Why Runoff rises when cover is lost.
Key terms in Applied Ecology (Elective)
Pollution: The release of harmful substances into the environment that damage organisms or ecosystems.
Eutrophication: The enrichment of water with nutrients that causes excessive algal growth and oxygen depletion.
Algal bloom: A rapid increase of algae in water, often caused by nutrient pollution.
Biological oxygen demand: A measure of the oxygen used by microorganisms decomposing organic matter in water.
Bioaccumulation: The build-up of a persistent substance in an organism over time.
Biomagnification: The increasing concentration of a pollutant along a food chain.
Indicator species: An organism whose presence or absence indicates the level of pollution in an environment.
Conservation: The protection and careful management of natural resources and ecosystems.
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