1 markThe diagram below shows a food chain
grass → locusts → snakes → eagles
If the number of snakes decreases due to disease, what will happen to the numbers of the other organisms in the food chain?
| grass | locusts | eagles | |
| A | increase | increase | increase |
| B | increase | decrease | increase |
| C | decrease | decrease | decrease |
| D | decrease | increase | decrease |
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1 markWhich of the following factors does NOT affect the rate of decomposition of biological material within an ecosystem?
Availability of oxygen
Presence of predators nearby
Temperature
Availability of water
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1 markThe diagram below illustrates part of the carbon cycle.
Which process is shown by the arrow labelled Y?
Photosynthesis
Feeding
Respiration
Combustion
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1 markWhich of the following options shows four ecological terms in a logical order, starting with the smallest and ending with the largest?
individual → community → population → ecosystem
population → individual → ecosystem → community
community → population → ecosystem → individual
individual → population → community → ecosystem
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1 markWhich of the following diagrams shows a pyramid of biomass for a marine ecosystem?
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1 markThere are different levels of organisation within an ecosystem.
What is the correct order of these levels?
individual, community, population, ecosystem
community, individual, ecosystem, population
individual, population, community, ecosystem
population, community, ecosystem, individual
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1 markLook at the information about a food chain.
| Organism | Number | Biomass |
| Oak tree | 1 | 500,000 |
| Aphids | 10,000 | 1,000 |
| Ladybirds | 200 | 50 |
Calculate the percentage biomass of the aphids transferred to the ladybirds.
0.05%
20%
5%
2000%
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1 markThe diagram shows a food web.
What is the most likely effect on the food web, if the number of cod decreases?
An increase in the number of herrings
An increase in the number of krill
An increase in the number of sharks
No effect on the population of puffins
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1 markLook at the pyramid of biomass.
What can you tell from this pyramid of biomass?
All four trophic levels contain consumers.
Fleas are producers.
The trophic level with oak trees has the lowest biomass.
There are fewer birds than caterpillars.
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1 markOrganisms in an ecosystem are affected by biotic factors.
Which term is a biotic factor?
Disease
Light intensity
Rainfall
Wind speed
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1 markIn food chains, biomass is lost between different trophic levels.
One reason for this is the release of undigested food from the body.
Which term is used to describe this release?
Decomposition
Egestion
Excretion
Peristalsis
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1 markWhich of these is an abiotic factor that can affect organisms?
Food availability
Light intensity
Pathogens
Predators
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1 markThe diagram shows the water cycle.
Which label, A, B, C or D, represents evaporation?
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1 markWhich relationship describes an organism living on an animal and harming it?
Decomposition
Mutualism
Parasitism
Predation
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1 markMost food chains only have a maximum of five trophic levels.
Explain why.
Organisms always get larger at higher trophic levels.
Energy is lost at each trophic level.
It is more energy efficient to eat meat than plant material.
The number of organisms feeding always increases at higher trophic levels.
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1 markWhich process in the carbon cycle takes in carbon dioxide from the air?
Combustion
Decomposition
Photosynthesis
Respiration
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1 markThe diagram shows a pyramid of biomass.
Which trophic level is X?
Primary consumers
Producers
Secondary consumers
Tertiary consumers
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1 markWhich is the correct definition of a parasite?
An organism that is always at the top of a food chain.
An organism that kills and eats another organism.
An organism that lives on another living organism so that they both benefit.
An organism that lives on or in another living organism causing it harm.
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1 markThe diagram shows a food web in the sea.
The number of penguins decreased in the area. This caused an increase in seal numbers.
What is a possible reason for the increase in seal numbers?
Fewer seals were eaten.
The krill numbers dropped.
There were more plankton for the seals to eat.
The seals had less competition for squid.
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1 markThe diagram shows pyramids of biomass for two food webs, X and Y.
Which statement explains the difference between the two pyramids?
In food web X there is a greater efficiency of transfer between primary consumer and secondary consumer than in Y.
In food web X there is a greater efficiency of transfer between secondary consumer and tertiary consumer than in Y.
In food web X there is a lower efficiency of transfer between primary consumer and secondary consumer than in Y.
In food web X there is a lower efficiency of transfer between secondary consumer and tertiary consumer than in Y.
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1 markThe diagram shows part of a cycle in an ecosystem.
What is the name of the cycle shown in the diagram?
Carbon cycle
Hydrogen cycle
Nitrogen cycle
Sulfur cycle
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1 markGoldfish are a species of fish.
What name is given to all the goldfish living in a pond?
A community
An ecosystem
A habitat
A population
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1 markThis is a food chain for organisms in a forest.
Oak tree ⟶ Greenfly ⟶ Ladybird ⟶ Blackbird
Which is the correct shape for a pyramid of biomass for this food chain?
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