Q1.          The diagram shows the annual energy flow through 1 m2 of a habitat.
The unit, in each case, is kJ per m2 per year.

(a)     Calculate the percentage of the energy absorbed by the grass from sunlight that is transferred to the frog.
Show clearly how you work out your answer.
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                                      Answer ....................................................... %	   (2)
(b)     All of the energy the grass absorbs from the sun is eventually lost to the surroundings.
In what form is this energy lost?
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(c)     Food chains are usually not more than five organisms long. Explain why.
To gain full marks you must use data from the diagram.
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(2)
(d)      In this habitat microorganisms help to recycle materials.
Explain how.
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(3)
(Total 8 marks)
The information in the table compares two farms. Both are the same size, on similar land, close to one another and both are equally well managed.
Name of farm	Activity	Energy value of
food for humans
produced in
one year	Number of people whose
energy requirements
can be met by
this food	
Greenbank Farm	Grows food for
humans	3285 million kJ	720	
Oaktree Farm	Grows food for
animals on the
farm which become
food for humans	365 million kJ	80	
           (a)     Use this information to work out the average daily human energy requirement in kilojoules (kJ) per day.
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Energy requirement = ................................. kJ/day
(2)
(b)     The figures show that farms like Greenbank Farm can be nine times more efficient at meeting human food energy requirements than farms such as Oaktree Farm.
(i)      The food chain for Greenbank Farm is:
vegetation   →   humans
         What is the food chain for Oaktree Farm?
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(1)

(ii)     Explain why Greenbank Farm is much more efficient at meeting human food energy requirements.
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(c)     The human population has been increasing rapidly throughout this century. It is now about 6 billion and is still growing. What does the information in this question suggest about likely changes in the human diet which may need to occur during the coming century? Explain your answer.
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(Total 10 marks)
 Q3.          The drawings show changes to a farm between 1953 and 1983.

          The fields on the farm are separated by hedges.
(i)      Give two major changes which were made to the land on this farm between 1953 and 1983.
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2 ..................................................................................................................................
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(2)
(ii)      How would these changes affect the number of wild animals which live on the farmland?
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          Explain your answer.
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(2)
(Total 4 marks)
 Q4.          (a)     The world-wide use of fossil fuels has increased rapidly during this century.
(i)      Give two reasons for the increase in the amount of fossil fuels used.
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2 ........................................................................................................................
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(ii)     Give two effects on the environment of this increase in the amount of fossil fuels used.
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2 ........................................................................................................................
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(b)     Describe and explain the long term effects of large-scale deforestation on the Earth’s atmosphere.
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(4)
(Total 8 marks)

Q5.         The diagram shows the annual flow of energy through a habitat.
The figures are in kJ m–2.

(a)     (i)      Calculate the percentage of the energy in sunlight that was transferred into energy in the green plants.
Show clearly how you work out your answer.
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                                                   Answer = ........................................ %
(2)
(ii)     Suggest reasons why the percentage energy transfer you calculated in part (a)(i) was so low.
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(b)     Compare the amount of energy transferred to the insect-eating birds with the amount transferred to the predatory birds.
Suggest explanations for the difference in the amount of energy transferred to the two types of bird.
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(Total 7 marks)
Q6.          The diagram shows the amounts of energy that are transferred, over a period of time, through some living things in a grassland habitat.

(a)     Calculate the amount of energy transferred from the grass to the cows.
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Amount of energy = ..................................................... kJ
(1)
(b)     X is a process in plants.
(i)      Calculate the amount of energy usefully transferred by process X.
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Amount of energy = ..................................................... kJ
(1)
(ii)     Name process X.
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(c)     Give two ways in which energy is ‘lost’ from the cows at Y.
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(d)     Describe how hormones can be used to improve the efficiency of producing food from plants.
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(Total 7 marks)
 Q7.          A gardener pulled up weeds and used them to start a compost heap. The compost heap soon became colonised by large numbers of earthworms and slugs. The gardener then noticed a hedgehog rooting through the compost heap, eating the earthworms and slugs. Every so often the hedgehog stopped to scratch itself. This was because it had large numbers of fleas which fed by sucking the hedgehog’s blood.
(a)     Use only information from the passage to answer the following.
          Construct and label a pyramid of biomass for your food chain.

(2)
(b)     Gardeners put plant material onto compost heaps so that it will decay. They then put the decayed compost onto soil where they are growing their plants.
          Give three conditions which are needed for plant material to decay rapidly.
1 .....................................................................
2 .....................................................................
3 .....................................................................                                   (3)
(Total 5 marks)
 Q8.          The table shows energy transfers in a large insect and a small mammal.
Both animals feed mainly on grass.
 
Energy transfer	Amount of energy in kJ.	
	Large insect	Small mammal	
Eaten as grass	4.00	25.00	
Absorbed into body	1.60	12.50	
Leaves body as faeces	2.40	12.50	
Production of new tissue	0.64	0.25	
Transferred by respiration	0.96	12.25	

(a)     What percentage of the energy in food is transferred into new tissue in the large insect?
Show clearly how you work out your answer.
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                              Answer = ............................................................ 
(2)
(b)     The proportion of energy in the food transferred into new tissue is much greater in the large insect than in the small mammal.
Explain why as fully as you can.
You should include references to the data in your answer.
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(3)
(Total 5 marks)
M1.          (a)    0.18
award both marks for correct answer irrespective of working
if no answer or incorrect answer
allow 1 mark for 45 × 100 / 25000
2
(b)     heat / thermal
allow heat from respiration
1
(c)     energy / mass / biomass lost / not passed on or energy / mass / biomass
is used or not enough energy / mass / biomass left
ignore reference to losses via eg respiration / excretion / movement / heat						1
a sensible / appropriate use of figures including heron
eg only 2 from frog / to heron
ignore units							1
(d)     any three from:
accept marking points if candidate uses other terms for microorganisms
•        (microorganisms) decay / decompose / digest / breakdown / rot 
ignore eat
•        (breakdown) releases minerals / nutrients / ions / salts / named
ignore food
•        (microorganisms) respiration 
ignore other organisms respiring
•        (microorganisms / respiration) release of carbon dioxide
3
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 M2.          (a)     12 500
incorrect numerical answer but clear evidence of correct working e.g. 365 million ÷ 365 ÷ 80 or 3285 million ÷ 365 ÷720 credit with (1)
2
(b)     (i)      vegetation
→ (farm) animals → humans
accept any correct variation on this theme 
e.g. grass → lambs → humans
1
(ii)     any three linked points from
         * less links in the food chain
or only one link in the food chain
         * energy ‘wasted’ or ‘lost’ or
   ‘used’ at each link
* energy ‘wasted’ or ‘lost’ in (the
   process of) respiration
* energy ‘used’ to maintain body
   temperature
* energy ‘used’ by the animals in
   movement
3
(c)     people will eat more/greater proportion
of food from plants
accept people will eat less/smaller proportion of food from animals
do not credit ‘everyone will stop eating meat’
1
          any three linked points from
these marks are independent of the ‘prediction’ mark
do not credit ‘food from plants will become less expensive’
          * meat will become more expensive
* only a limited area of land
  available on the planet (for food
  production or otherwise)
* more people means less land
  available for food production
  because some used for housing etc.
* land will become more expensive
* land will have to be used more
  efficiently
or more people will go hungry
or people will (each) eat less
          * livestock farmers will try to improve efficiency
* (leading to) growth of ‘factory farming’
* demand for food will rise (total)
3
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 M3.          (i)      fewer hedges
marsh drained
less woodland/trees
more farm buildings
any  2 for 1 mark each
2
(ii)      fewer
e.g. fewer habitats
for 1 mark each
2
[4]
 M4.          (a)     (i)      2 of:
increase in population
increase in living standards
example
any 2 for 1 mark each
2
(ii)     pollution effects OWTTE
destruction of habitats by extraction methods
gains 2 marks
(allow 2 pollution effects)
2
(b)     4 of e.g.
trees can no longer photosynthesise
removing carbon dioxide from atmosphere and ‘locking it away’ long term
increased carbon dioxide concentration leads to more 
absorption of reflected energy atmosphere therefore warms 
any 4 for 1 mark each
4
[8]

M5.          (a)     (i)      0.6 or 6 x 10-1
for correct answer
if no / incorrect answer
or
0.006 or 6 x 10-3 gains 1 mark
2
(ii)     any two from:
•        reflected
ignore some of light is green
•        not absorbed or misses chloroplasts / chlorophyll
allow transmitted or passes through leaves
allow hits other plant parts 
•        wrong wavelength
•        photosynthesis inefficient
accept other limiting factors / named
•        allow some lost through respiration / as heat (from respiration)	2
(b)     energy lost via faeces / not digested / waste / excreted (of insect-eating birds)
1
energy loss via respiration / movement / muscle contraction / heat (by insect-eating bird)
accept examples of muscle contraction
do not accept energy used for respiration			1
some of (insect eating) bird not eaten but all / most / more of insect is eaten
1
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 M6.          (a)     3060 (kJ)
1
(b)     (i)      22060 (kJ)
1
(ii)     photosynthesis
1
(c)     faeces / undigested food
reference to movement and respiration are neutral
          urine / urea
2
accept excretion / waste / droppings if
both of the mark points are not gained
(d)     any two from
•        control ripening
•        herbicides
•        prevent over ripening in transport
•        stimulate root growth
other growth references are not neutral
•        use in tissue culture to produce large numbers of plantlets
2
[7]
 M7.          (a)     pyramid correct shape labelled
2

(b)     warm
moist
oxygen
3
[5]
 
M8.          (a)     16
accept correct answer for 2 marks, irrespective of working
if no answer or answer incorrect accept 0.64 x 100 / 4 (.0) or 0.16 for 1 mark
2

(b)     insect cold-blooded / not warm blooded or does not control body temperature
accept mammal warm-blooded / constant (high) body temperature / controls body temperature
1

reference to insect 0.96 (kJ) and mammal 12.25 (kJ) transferred by respiration
or relevant calculation of this transfer
ignore references to other data
1

(less respiration) so more energy / biomass / food available (for growth of insect)
(more respiration) so less energy / biomass / food available (for growth of mammal)
1
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