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4B Feeding relationships
Time: 1 hour 21 minutes
Total marks available: 81
Total marks achieved: ______
Andy Todd
Q1.
This food chain shows feeding relationships in paddy fields in Sri Lanka and India.
(a) (i) Name the producer.
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(ii) Name the secondary consumer.
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(b) Give two environmental factors that could affect the growth of the rice crop.
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(c) Suggest why a farmer might choose to use a chemical pesticide in his paddy field.
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(d) Describe how the farmer could use biological control in his paddy field.
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(Total for question = 8 marks)
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Q2.
Here is a food chain.
(a) (i) Use the information in this food chain to complete the diagram.
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(ii) Name one type of organism that is a decomposer.
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(b) Decomposition is a stage in the carbon cycle. The other stages are respiration,
photosynthesis and combustion.
How many of these four stages add carbon dioxide to the air?
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(Total for question = 5 marks)
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Q3.
The diagram shows part of a food web in an oak forest.
(a) Use the information in the food web to complete the statements in the table.
The first one has been done for you.
(4)
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(b) (i) What effect would a decrease in the population size of caterpillars have on the
population size of blue jays?
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(ii) What is meant by the term population?
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(c) The tick feeds on deer by sucking their blood.
Name two different molecules that are found in the blood of deer that the tick
could feed on.
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(Total for question = 8 marks)
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Q4.
Pigeons are birds that eat seeds. They are hunted by predators called hawks.
(a) Use this information to draw a food chain in the space below.
(2)
(b) Pigeons often feed in small groups. The size of the group of pigeons affects the
success rate of a hawk in catching a pigeon. Pigeons use their eyes to see an
approaching hawk.
The table gives information about the success that a hawk has in catching pigeons
when pigeons are in different group sizes.
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(i) Use the information in the table to describe and explain the relationship
between the size of a group of pigeons and the success rate of the hawk.
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(ii) Describe the changes that would take place in the eye of a pigeon to help it
focus on an approaching hawk.
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(iii) Describe what happens to protein from pigeon meat when it is in a hawk's stomach.
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(Total for question = 11 marks)
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Q5.
Caterpillars feed on hawthorn bushes. The caterpillars are eaten by small birds such as
the dunnock. The dunnocks are preyed on by a larger carnivorous bird, the sparrowhawk.
This data was collected from a hedgerow.
(a) Use the information in the table to draw an accurate pyramid of numbers for this
data on the grid below.
(4)
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(b) Describe how a pyramid of biomass from the same data would differ from the
pyramid of numbers.
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(c) Explain why not all the energy in a producer passes to the primary consumer.
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(d) Some farmers are removing hedges in order to increase the size of their fields.
This means that the number of hawthorn bushes is decreasing.
Suggest how removing hawthorn bushes will affect the size of the dunnock population.
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(Total for question = 10 marks)
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Q6.
The table describes four different geographical regions. It also gives the amount of energy
converted into plant biomass each year in each region.
(a) Plot a bar graph on the grid to show the amount of energy converted into plant
biomass each year in each region.
(5)
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(b) The amount of energy converted into plant biomass each year depends on the
effect that abiotic (non-living) factors have on the rate of photosynthesis.
Carbon dioxide is one of these abiotic factors.
Name three other abiotic factors likely to affect the rate of photosynthesis.
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(c) Regions C and D have the same climate. Plants grown in region D have more
energy converted into plant biomass than plants grown in region C. One reason
for this is the use of selective breeding to produce high yielding crops.
(i) Suggest two other reasons for more energy being converted into plant
biomass in region D.
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(ii) What is meant by the term selective breeding?
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(d) Describe how you could use a quadrat to estimate the plant biomass in one of the regions.
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(Total for question = 18 marks)
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Q7.
The photograph shows a bird called a parakeet.
(a) (i) Parakeets eat seeds.
Parakeets can be eaten by birds of prey called raptors.
Use this information to draw a food chain.
(2)
(ii) Many seeds contain starch.
Suggest what happens to starch in the gut of a parakeet.
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(b) (i) The graph shows the volume of oxygen used by a resting parakeet compared
to a flying parakeet.
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Calculate the extra volume of oxygen used in litres per gram per hour when
flying compared to the volume used at rest.
Show your working.
(2)
Answer ........................................................... litres per gram per hour
(ii) Like humans, parakeets need to keep their body temperature constant.
Suggest how the volume of oxygen used by a parakeet at rest would change
if it was moved to a colder environment.
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(Total for question = 10 marks)
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Q8.
A student was told that farming animals outdoors was less efficient than keeping
them indoors (factory farming). The student investigated this idea, using beakers of
hot water to represent the animals, with the apparatus shown below. The cardboard
box was used to represent keeping animals indoors.
The beakers were filled with the same volume of hot water and the temperature in
each beaker was measured at intervals of 10 minutes over a period of 30 minutes.
The investigation was repeated five times. The results are shown in the table.
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(a) (i) How many times did the student measure the temperature of the water in the
beakers outside the box during the investigation?
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(ii) The diagram shows one of the temperature readings during the investigation.
Use the diagram and the information in the table to complete the following
sentence.
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The reading on this thermometer is ........................ °C, which suggests the reading was
taken from a beaker after ........................ minutes kept
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(b) (i) What was the independent variable (the variable that the student chose to
change) in this investigation?
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(ii) What was the dependent variable (the variable measured by the student) in
this investigation?
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(iii) Explain why the student kept the other variables constant.
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(c) The student tried to make his measurements accurate.
Give one way that he could have done this.
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(d) The results of this investigation suggest that meat production would be less
efficient if farmers kept their animals outdoors rather than indoors.
Use the data and your knowledge to explain why.
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(Total for question = 11 marks)
Q1.
This question showed a food chain from Asia and in (a) almost all the
candidates were able to correctly identify the producer and secondary
consumer. In (b) many candidates could correctly give two environmental
factors that affect the growth of the rice. Some answers were too vague
such as weather or climate and others mentioned biotic factors such as
pests. In part (c) the more able candidates were able to explain how a
pesticide would kill the beetles and therefore increase the rice yield.
In (d) the best responses described how by releasing a predator such as an
Asian toad the beetles would be eaten. Some candidates chose
inappropriate predators such as cats or even wrote about fertilisers.
Q2.
This question presented a food chain and in part a) candidates had to use the
information to complete a diagram, almost all gained full marks. Although
most candidates could name one type of decomposer some suggested rose
or another organism from the food chain. Part b) was correctly answered by
most candidates. Candidates had no difficulty with parts c) and d).
Q3.
Part (a) gave part of a food web and students had to determine the number of different groups in
the web. Most students had no difficulty with this item with the few errors observed being for the
number of secondary consumers. In part (b)(i) most responses correctly predicted that the
population of blue jays would decrease. Some students gave the reason for the change but did
not state the effect on the population size. In part (b) (ii) a significant number of students were
unable to state the meaning of population and the 'number of animals' or the 'number of people'
were given. For (c) most could give two molecules that the tick could feed on from the deer's
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blood. A few students put blood cells or starch as suggestions.
Q4.
Most candidates coped well with having to draw the food chain, though a
surprising number included organisms not mentioned in the question. An
equally surprising number failed to put the arrows in the correct direction. In
(b)(i), most were able to appreciate that a hawk had more success with a
smaller number of pigeons in a group, but only the better candidates went on
to give a sensible explanation. Part (b) (ii) examined student knowledge of the
eye and a pleasing number of candidates appreciated the role of the ciliary
muscle, the suspensory ligaments and the lens in helping to focus on an
approaching hawk. Considerable confusion existed about the contraction /
relaxation, tightening / slackening and fattening / thinning of these eye parts.
The role of circular and radial muscles was not credited. Most candidates were
able to describe what happens to protein in the stomach and it was common
to award full marks for this part of the question.
Q5.
Students were given a food chain and data from which they had to plot an
accurate pyramid of numbers. Although many gained full marks in (a), some
presented the data in the wrong order or did not draw the pyramid to scale. In
(b), most could describe how a pyramid of biomass would be a regular pyramid
and that the producers would have a larger biomass than for example the primary
consumers. In (c), some candidates did not realise the question asked about
energy transfer from the producer to the primary consumer so that answers
referring to losses due to movement or excretion were not relevant. The best
candidates gained full credit for describing losses due to respiration in the plant
and the primary consumer not eating all of the plant or not being able to digest
some parts of it. Many candidates gained full marks for describing how the
removal of the bushes would decrease the caterpillar population and therefore
reduce the dunnock population.
Q6.
In part (a) of this question most students were able to score at least 4 marks with excellent bar
charts. The most common loss of a mark was for not labelling the axes fully, including
appropriate units. Part (b) was well answered with most showing good understanding of abiotic
factors that affect photosynthesis, temperature and light being the most common responses. A
few gave vague references to humidity and wind speed confusing it with transpiration. Part (c)(i)
was challenging for many. The mark scheme rewarded students who appreciated that farming
practices improve primary production. The better students made the connection and scored well
but the weaker students made bland references to photosynthesis or made vague references to
farming intensity. Student understanding of selective breeding in part (ii) was impressive with
many appreciating that human involvement is part of the process. In part (d), many students had
no understanding of how to use quadrats. Students who were familiar with the technique scored
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at least two marks for mentioning the importance of random sampling and repeats. The question
asked for an estimate of biomass not numbers but most students referred to counting plants
rather than weighing them.
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Q7.
In this question the style of question asked in part (a)(i) has been a feature of several past
papers and yet there are still students who draw pyramids of biomass, or put the arrows in the
wrong direction. These students could still gain one mark providing they wrote all three names
and put the parakeet in the middle. Part (a)(ii) was answered very well and it was pleasing to
note that most students are aware of the digestion of starch by amylase into maltose. In part (b),
most were able to correctly calculate 25.5 as the volume of oxygen used when flying in part (i),
but many struggled in part (ii) to gain all three marks. Most appreciated that the volume of
oxygen used would increase but only the best students appreciated the link between this and the
need to respire more because of the heat loss that would occur when moving to a colder
environment.
Q8.
Part (a) was well-answered with most being able to work out that the student
measured the temperature twenty times in the beakers outside the box, and
that the thermometer reading was 54 °C after 10 minutes kept inside the box.
Part (b) was more challenging, but many were able to note that the
independent variable was linked to the positioning of the beakers inside or
outside the box, and that the dependent variable was the measurement of
temperature. The examiners were pleased to note that in part (iii) many
students made reference to the need to keep other variables constant to ensure
a fair test that allows a valid comparison of the results to be made because no
other variable, other than the independent variable, is having an influence on
the results. Students also seem to have a decent grasp on what the term
accurate means with most making reference to parallax error, stirring the water
or using a thermometer with finer divisions. Other acceptable responses were
rewarded. Weaker students wrote about the need for replication and answered
the question as though reliability was being asked, not accuracy. Part (d) was
challenging to candidates. Many did appreciate that animals kept outdoors
would lose more heat and that this would need to be replaced by respiration of
food if the animals were to maintain their body temperature. However, the
expression of these ideas was often convoluted and difficult to decipher.
Candidates are encouraged to think carefully about their ideas before starting to
write their answers in order to improve the clarity of their responses.
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Q1.
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Q2.
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Q4.
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Q6.
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Q8.
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