Question 1
What is meant by a community in ecology?
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All the populations of different species living in a habitat
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All abiotic factors in one ecosystem
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All individuals of one species only
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All decomposers in a food web
Question 2
Which is a biotic factor in an ecosystem?
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Competition for food
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Light intensity
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Soil pH
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Temperature
Question 3
Which is an abiotic factor in an ecosystem?
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Moisture level
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Predation
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Disease-causing microorganisms
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Availability of prey species
Question 4
Why are microorganisms important as decomposers?
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They break down waste and dead material, recycling nutrients
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They produce oxygen by photosynthesis in all habitats
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They remove all carbon dioxide from air
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They prevent any disease transmission
Question 5
In food chains, about what percentage of biomass is typically transferred to the next trophic level?
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Around \(10\%\)
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Around \(1\%\)
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Around \(50\%\)
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Around \(90\%\)
Question 6
Why does biomass usually decrease at higher trophic levels?
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Not all biomass is transferred because energy is lost at each stage
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Predators do not respire
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Producers never die
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Top consumers make glucose by photosynthesis
Question 7
What is the main purpose of a quadrat in fieldwork?
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To estimate abundance or distribution of organisms in a sample area
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To measure pH in blood
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To trap fast-moving predators
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To sterilise soil before counting
Question 8
Why is random sampling used with quadrats?
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To reduce sampling bias
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To guarantee every species is counted
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To increase competition between species
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To make decomposition faster
Question 9
What is a transect used for in ecology?
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To study how organisms change across a habitat gradient
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To identify blood groups in a population
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To separate biotic and abiotic factors chemically
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To measure oxygen uptake in athletes
Question 10
Decay by microorganisms is generally fastest in which conditions?
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Warm, moist and aerobic
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Cold, dry and anaerobic
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Cold, moist and acidic only
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Warm, dry and no oxygen
Question 11
What happens to decomposition rate if temperature falls a lot?
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It usually decreases
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It usually increases sharply
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It stays exactly the same
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It becomes independent of microorganisms
Question 12
In composting, which organisms mainly carry out decomposition?
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Bacteria and fungi
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Red blood cells
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Viruses only
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Root hair cells
Question 13
Which gas produced by decomposition in landfill contributes to global warming?
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Methane
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Nitrogen
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Hydrogen
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Oxygen
Question 14
What often triggers eutrophication in freshwater?
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Nitrate and phosphate ions
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Dissolved oxygen
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Glucose and amino acids
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Carbon monoxide and sulfur dioxide
Question 15
Why can eutrophication kill fish?
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Decomposition of dead algae uses up dissolved oxygen
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Extra nutrients stop all algae growth
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Fish cannot respire in warm water
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Carbon dioxide concentration falls to zero
Question 16
How can deforestation reduce biodiversity?
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It destroys habitats and food sources for many species
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It increases habitat variety immediately
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It prevents climate change completely
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It eliminates all competition between organisms
Question 17
Why can peat bog destruction increase atmospheric carbon dioxide over time?
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Stored carbon is released when peat is drained or burned
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Peat bogs absorb no carbon
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Peat formation is faster than burning
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Carbon dioxide turns into oxygen in dry peat
Question 18
Which method helps conserve biodiversity?
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Maintaining seed banks and breeding programmes
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Clearing old forests for monoculture farming
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Releasing untreated sewage into rivers
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Increasing landfill use instead of recycling
Question 19
Why is maintaining high biodiversity often linked to ecosystem stability?
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More species and interactions can make systems more resilient to change
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High biodiversity removes all pathogens
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High biodiversity prevents all abiotic stress
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High biodiversity means no natural selection
Question 20
Why is fish stock management needed in some seas?
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To prevent overfishing and allow populations to recover
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To eliminate predator species
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To raise ocean temperature for faster growth
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To increase eutrophication for plankton blooms