Energy flow

Which order shows how energy moves through an ecosystem?

May/June 2015

The diagram illustrates a food web. What is most likely to happen to the owl population if foxes die out?

May/June 2015

Some organisms inhabit the seabed, where the surroundings are extremely dark. To synthesise glucose, they obtain energy from chemicals in the superheated water released from volcanoes. What is a distinguishing characteristic of these organisms?

May/June 2015

The diagram illustrates a food web. Which statement about this food web is correct?

May/June 2015

The diagram illustrates the movement of substances through an ecosystem. The circles stand for trophic levels. Which circle shows herbivores?

May/June 2016

The diagram illustrates the movement of substances through an ecosystem. The circles stand for trophic levels. Which circle shows the herbivores?

May/June 2016

Why must an ecosystem receive regular exposure to sunlight?

May/June 2017

The diagram represents a food chain. tree  mice  cats  fleas What form would the pyramid of numbers take for this food chain?

May/June 2017

Why is it necessary for an ecosystem to receive sunlight at regular intervals?

May/June 2017

The leaves of a tree are eaten by insects. Those insects are then eaten by small birds, which are themselves preyed on by larger birds. Which pyramid of numbers shows this food chain?

May/June 2017

A simple food chain is shown here: tree → insect → bird → fox

May/June 2017

The graph illustrates how the populations of plant plankton and animal plankton in a lake change over time. Consider the following statement in relation to the data shown on the graph. ‘Changes in the population of animal plankton occur later than similar changes in plant plankton because the animals eat the plants.’ Which category does the statement belong to?

May/June 2018

Which sequence constitutes a food chain?

May/June 2018

The graph illustrates how the populations of plant and animal plankton in a lake change over time. With reference to the information shown on the graph, consider this statement: 'Population changes in animal plankton lag behind similar changes in plant plankton because the animals feed on the plants.' Which category does this statement belong to?

May/June 2018

A food chain is illustrated. grain $$ insects $$ small birds $$ owls $$ lice What would the pyramid of numbers be for this food chain?

May/June 2018

The diagram presents a food web in a pond.

May/June 2018

In the long run, what happens to all the energy present in an ecosystem?

May/June 2019

Which statement about the organisms found at the start of food chains is correct?

May/June 2019

What ultimately becomes of all the energy in an ecosystem?

May/June 2019

Which statement correctly describes the organisms found at the start of food chains?

May/June 2019

These processes take place in living organisms within a food chain. Which of them would cause energy to be lost from a food chain?

May/June 2021

Why is the flow of energy through an ecosystem described as non-cyclic?

May/June 2021

A full food web is shown in the diagram. Which row gives examples of the organism types in this food web?

May/June 2021

A sycamore tree functions as a producer in many food chains in a forest ecosystem.

May/June 2021

The diagram depicts a biomass pyramid. What percentage of biomass is transferred from the primary consumer to the secondary consumer?

May/June 2023

Which process does not cause a net loss of energy from the organism?

May/June 2023

The diagram illustrates four ecological pyramids. In one food chain, cows feed on grass. Insects live on the cows’ skin. Birds eat the insects. Which one is the pyramid of biomass and which one is the pyramid of numbers in this food chain?

May/June 2023

The diagram presents a food web from an ecosystem. Which group of organisms in an ecosystem is missing from this food web?

May/June 2024

Within Africa’s grasslands, large herbivores, for example elephants, carry many parasites, including ticks. These ticks feed by sucking blood from the herbivores’ skin. The parasites then provide food for small birds known as oxpeckers. In turn, oxpeckers are food for goshawks. Which pyramid of numbers corresponds to this food chain?

May/June 2024

What is the main source of energy in most biological systems?

May/June 2025

What does the term food chain mean?

May/June 2025

Fig. 2.1 displays a pond food web.

May/June 2025

The diagram illustrates a food chain. mahogany tree $\rightarrow$ caterpillar $\rightarrow$ songbird $\rightarrow$ hawk Which category of organism occurs in the greatest numbers in this food chain?

Oct/Nov 2015

The diagram displays a food web. For which pair of animals is the largest amount of energy available?

Oct/Nov 2015

Fig. 2.1 depicts a sloth. This mammal lives in the trees of South American rainforests. Sloths are described as having several features linked to feeding, movement, predators, and their associations with algae, moths, and mosquitoes.

Oct/Nov 2015

The diagram presents a food chain. mahogany tree $\rightarrow$ caterpillar $\rightarrow$ songbird $\rightarrow$ hawk What substance is not recycled from the hawk back to the mahogany tree?

Oct/Nov 2016

The diagram illustrates a pyramid of numbers. Which food chain does this pyramid of numbers represent?

Oct/Nov 2016

Which statement correctly describes the flow of energy through an ecosystem?

Oct/Nov 2016

The diagram illustrates a pyramid of biomass. What percentage of biomass is transferred from the primary consumer to the secondary consumer?

Oct/Nov 2016

The diagram represents a food chain: grass $\rightarrow$ rabbit $\rightarrow$ fox $\rightarrow$ flea. Which pyramid of numbers corresponds to this food chain?

Oct/Nov 2017

The diagram illustrates a food chain. grass $\rightarrow$ rabbit $\rightarrow$ fox $\rightarrow$ flea Which pyramid of numbers corresponds to this food chain?

Oct/Nov 2017

Fig. 3.1 illustrates the movement of energy through a biological system.

Oct/Nov 2017

The diagram illustrates a section of a food web. Which pyramid of numbers is derived from this food web?

Oct/Nov 2018

Certain organisms inhabit the seabed, where there is almost no light. In order to synthesise glucose, they obtain energy from chemicals in the extremely hot water discharged by volcanoes. What is one distinguishing characteristic of these organisms?

Oct/Nov 2018

Which organisms always derive their energy from dead organic matter?

Oct/Nov 2018

The diagram illustrates a section of a food web. Which pyramid of numbers is built from this food web?

Oct/Nov 2018

A few organisms inhabit the bottom of the sea, where darkness is extreme. In order to synthesise glucose, they gain energy from chemicals in the extremely hot water discharged by volcanoes. What is one distinguishing feature of these organisms?

Oct/Nov 2018

The diagram illustrates a food web. In this web, what is meant by a food chain?

Oct/Nov 2019

Why is the flow of energy in an ecosystem regarded as non-cyclic?

Oct/Nov 2019

Each square metre of grassland receives $1\,004\,000\,\text{kJ}$ of sunlight energy per year. The table illustrates how this energy is used. How much of the $1\,004\,000\,\text{kJ}$ of sunlight energy was used by the grass plants?

Oct/Nov 2019

Explain how energy originating from the Sun may ultimately be used in active transport within the alimentary canal.

Oct/Nov 2019

Mealybugs are tiny insects that feed on crops such as mango and coffee. They harm the crops and lower the yield and profits for farmers. Lacewing insects and ladybird beetles both feed on mealybugs. Which row shows the positions of some of the organisms in this food chain?

Oct/Nov 2020

The diagram shows a food web of organisms in a pond. Which organism is a herbivore as well as a carnivore?

Oct/Nov 2020

Explain how the energy that first comes from the Sun is ultimately used to drive the muscles of a lion when it runs.

Oct/Nov 2020

In a pyramid of biomass, the biomass of the producers is $800\,\text{g m}^{-2}$. What are the probable biomass values of the herbivores and the carnivores?

Oct/Nov 2021

What does the term food chain mean?

Oct/Nov 2021

The kapok tree is a flowering plant that grows very quickly until it becomes one of the tallest trees in a tropical rainforest ecosystem. Climbing plants twine around its stem, and the tree offers a habitat for insect-eating birds and frogs. Bats feed on nectar from its flowers and pollinate them, allowing the tree to make small, light seeds. Insects eat its leaves, and when the leaves drop to the ground they come into contact with soil bacteria and fungi.

Oct/Nov 2021

What is the main source of energy entering biological systems?

Oct/Nov 2022

The diagram presents a food web in a grassland habitat.

Oct/Nov 2022

The diagram illustrates a food chain. mahogany tree $\rightarrow$ caterpillar $\rightarrow$ songbird $\rightarrow$ hawk. Which organisms are found in the greatest numbers in this food chain?

Oct/Nov 2023

In a tree, insect larvae tunnel through its leaves. The insects that emerge are then consumed by birds, and parasitic fleas live among the birds’ feathers. For this food chain, which pyramid represents biomass and which pyramid represents numbers?

Oct/Nov 2023

Fig. 2.1 depicts a reindeer. Reindeer inhabit treeless regions of the Arctic. In certain months of the year, reindeer feed mainly on grasses, ferns and mosses. Wolves and brown bears eat reindeer.

Oct/Nov 2023

Which row shows the organisms in a food chain?

Oct/Nov 2024

The diagram presents the pyramid of energy for this food chain: grass $\rightarrow$ grasshopper $\rightarrow$ bluebird. A pyramid of energy indicates the total amount of energy contained in the biomass of organisms at each trophic level in the food chain per year. To one decimal place, what percentage of energy is passed from the producer to the herbivore?

Oct/Nov 2024

The diagram illustrates a food web. Which organisms in this food web are primary consumers?

Oct/Nov 2025

The processes shown take place in living organisms in a food chain. 1 excretion 2 photosynthesis 3 respiration Which of these processes cause energy to be lost from a food chain?

Oct/Nov 2025

The diagram represents a food chain: large tree → small insect → small bird → large bird. Which pyramid of numbers corresponds to the food chain shown?

Oct/Nov 2025

Energy passes out of a food chain as it moves from one trophic level to the next. In which ways is energy lost from a food chain? 1. by egestion 2. by respiration 3. by photosynthesis 4. by excretion

Oct/Nov 2025