Energy flow
19.1What the syllabus asks of you
- Understand that the Sun is the principal source of energy input to most biological systems
- Explain why most forms of life are completely dependent on photosynthesis
- Describe the flow of energy through food chains and webs including energy from light and energy in living organisms and its eventual transfer to the environment
- Construct and interpret simple food chains
- Understand the terms producer, consumer, herbivore, carnivore and decomposer
- Describe food webs as networks of interconnected food chains and construct and interpret them
- Explain why the transfer of energy from one trophic level to another is inefficient
- Explain why food chains usually have fewer than five trophic levels
- Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants
- Construct and interpret pyramids of numbers, biomass and energy
Read the notes first
Chapter 19: Energy flow
Drill this topic
Every question on Energy flow, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
12 questions
1Oct / Nov 2020 · Paper 11 · Q29Show mark scheme →
Alacewing | mealybug | coffee
Bcoffee | mealybug | lacewing
Cmealybug | ladybird | mango
Dmango | ladybird | mealybug
Mark scheme
2Oct / Nov 2020 · Paper 12 · Q28Also set in Oct / Nov 2020 Paper 11Show mark scheme →
ACarbohydrates are passed from decomposers to producers.
BEnergy is passed from carnivores to herbivores.
CProteins are passed from primary consumers to producers.
DCarbohydrates are passed from producers to herbivores.
Mark scheme
3Oct / Nov 2020 · Paper 12 · Q29Show mark scheme →
Aalgae
Bdragonfly larva
Cmosquito larva
DParamecium
Mark scheme
4May / June 2020 · Paper 11 · Q28Show mark scheme →
AEnergy can be transferred back to its original source.
BEnergy is not transferred from living things to their environment.
CEnergy is only transferred from smaller to larger organisms.
DEnergy is transferred from living organisms as heat.
Mark scheme
5May / June 2020 · Paper 11 · Q29Show mark scheme →
A
B
C
D
Mark scheme
6May / June 2020 · Paper 12 · Q28Show mark scheme →
Acarnivores
Bdecomposers
Cherbivores
Dproducers
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7May / June 2020 · Paper 12 · Q29Show mark scheme →
A[pyramid diagram A]
B[pyramid diagram B]
C[pyramid diagram C]
D[pyramid diagram D]
Mark scheme
8Oct / Nov 2019 · Paper 11 · Q29Show mark scheme →
Afleas → mouse → grasshopper → grass
Bgrass → seeds → mouse → fleas
Chawk → snake → rabbit → grass
Dseeds → mouse → praying mantis → snake
Mark scheme
9Oct / Nov 2019 · Paper 12 · Q28Show mark scheme →
AEnergy can only be passed on in the form it entered the ecosystem.
BEnergy can only be passed on to a larger organism.
CEnergy cannot be completely returned to its original source.
DEnergy cannot have its form changed within an organism.
Mark scheme
10Oct / Nov 2019 · Paper 12 · Q29Show mark scheme →
A500 kJ
B2000 kJ
C23 500 kJ
D24 000 kJ
Mark scheme
11May / June 2019 · Paper 12 · Q28Also set in May / June 2019 Paper 11Show mark scheme →
AIt is lost from the system as heat.
BIt is recycled by the decomposers.
CIt is used by the producers.
DIt is used by the top carnivore.
Mark scheme
12May / June 2019 · Paper 12 · Q29Also set in May / June 2019 Paper 11Show mark scheme →
AThey cause decay and provide minerals for the ecosystem.
BThey feed on animals and recycle energy.
CThey feed on plants and provide food for animals.
DThey absorb nutrients and photosynthesise.
Mark scheme