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Environmental Science
Subject Code: EVS5C
2005 External Examination Report
TASMANIAN QUALIFICATIONS AUTHORITY
General Comments
The marking examiners considered the Environmental Science exam paper in general to be very
good. It was fair with some challenging sections, eg the feedback question, and gave candidates
plenty of opportunity to show what they know and, by implication, what they don’t know. It was
acknowledged that a lot of hard work and thought went into its setting, and this was appreciated.
It would seem that candidates had plenty of time to complete the paper (with time left over in
some cases), others ran out of time. This is probably a reflection on how well they know the
subject matter and whether they need to look for information in their notes or not. There is a
concern that many candidates rely on their notes to such an extent that they copy out complete
statements and end up not addressing the question. Candidates should note that the information
at the beginning of a question is the context for the answer for all parts of the question.
Candidates who copy out notes without relating to the question scored few marks. Greater
emphasis needs to be given to candidates that the examiners are looking for understanding and
relevance rather than the ability to crudely ‘cut and paste’. This dependence on their notes
seems to actually prevent candidates from reading the question accurately and then responding
to it. Instead they write about the topic within the question in a general way without addressing
the specifics of the question.
The questions in Part 1 were easy and straight forward. Most candidates answered them well.
The teachers of this subject can be considered to have taught candidates to develop and evaluate
experiments very well. Because of the nature of the questions, the number of points that could
be made and the acceptable variations in the answers it was considered preferable to deduct
points for what was missing rather than allocate points for what was included.
In Part 2, some candidates wasted both time and the space provided for their answers by
rewriting much of the wording of the question, or needlessly restating, explaining or expanding
the information given, instead of using it as the jumping-off point for the answers that were
actually asked for. More practice is needed in reading questions carefully, and becoming
precisely focused on exactly what answer is required.
Candidates performed well in Part 3 overall.
Comments about Part 4 are that answers should address the data in the question: e.g. Q14 the
footprint was for a FA cup final; Q15 (a) the environmental factors for a wind farm
development; Q15 (b) the legislation for the wind farm development; Q16 the ESD principles in
forestry agreements.
There was some discussion about Question 16, which called for a discussion of ecologically
sustainable development principles of practices set out in various forestry agreements in
Tasmania. It was noted that since the changed syllabus, the topics forests, water and energy are
no longer listed for study as such. However, the syllabus does include depletion of natural
resources, eg forests, fisheries, etc, and also the study of topical issues. Forest management is an
ongoing issue in Tasmania, particularly so this year and as such it would be expected to be
covered, particularly with the recent community forest agreement set up between the State and
Federal governments. A suggestion was made that the question could have provided a choice
between forests or fisheries to allow for variation in teacher emphasis on particular issues. The
question was marked by considering discussion of the application of ecologically sustainable
development principles within forest management in Tasmania.
2005 External Examination Report
Environmental Science
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Subject Code: EVS5C
Candidates still need to develop their skills in Part 5 - analysis of data.
Written Examination
The following section specifically comments on candidates’ performance. Marking examiners
offer suggested answers to each question, followed by specific comment on aspects such as
how the question was assessed, where candidates gained or lost marks, where they had difficulty
in interpreting the question, or where candidates failed to comprehend what was required to
successfully answer the question. The suggested answers are by no means prescriptive.
Candidates providing different but valid answers were rewarded accordingly as noted by the
examiners.
Suggested Answers and Comments
Part 1 – Criterion 4
Question 1
(a)
Hypothesis:
Alternative one: Temperature affects the rate of photosynthesis.
Alternative two: An increase in temperature causes an increase in the rate of
photosynthesis.
(b)
Independent variable: increase in temperature.
(c)
Dependent variable: the rate of photosynthesis.
(d)
Fixed variables: light, water, CO2 , size and type of plants.
(e)
Yes, from 5 to 35o C the rate of photosynthesis increases in all the plants, but at 40o C it
decreases.
Comments
Either of the two hypotheses was acceptable but it was disappointing the almost all of the
candidates use the second one. The first alternative is a better hypothesis.
(a)–(c) Points were deducted for poor wording of hypothesis and independent and dependent
variables. A few candidates got them the wrong way around.
(d)
Points were deducted if candidates used aspects of the plants as more than one fixed
variable or used trivial variables.
(e)
Points were deducted if candidates fail to indicate that the data was consistent with the
hypothesis only up to 40o C.
2005 External Examination Report
Environmental Science
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Subject Code: EVS5C
.Question 2
(a)
Experiment
Set-up five Petri dishes lined with paper toweling and divided in half. Soak the paper
toweling as follows: Dish 1 – distilled water 0.0M. Dish 2 – 0.2M salt solution. Dish 3 –
0.4M salt solution. Dish 4 – 0.6M salt solution and Dish 5 –0.8M salt solution. Place 30
rye grass and 30 clover seeds in each dish. Cover the dishes and place them in a warm
dark place until all of the seeds that will germinate in dish1 have done so. Count and
record the number of each seed type that germinated.
Control: the seeds in distilled water – 0.0M salt.
Independent variable: The two types of seeds and the salt concentration.
Dependent variable: The number of each seed type that germinated.
Fixed variables: water, temperature, number of seeds, size and shape of dishes.
The experiment will need to be repeated several times to obtain more valid data.
The hypothesis would be supported if more rye grass than clover seeds germinated in the
dishes with high salt concentrations (dishes 3, 4, 5). It would not be supported if
germination rates were similar.
(b)
Field trials
Collect data from areas that are salt affected and have rye grass and clover to show that
there are more rye grass plants than clover plants. Compare this to areas that are not salt
affected. The two species could be planted in these areas to provide data. Field trials are
less reliable than laboratory investigations because many variables are difficult to control.
Comments
(a)
Points were deducted for each of the following:
a field investigation when a laboratory investigation was specified.
poorly worded or inadequate instruction on how to set up the experiment.
inadequate sample size.
lack of or inadequate control.
inaccurate, missing or poorly worded independent and dependent variables.
no indication of fixed variables.
no indication of the need to repeat the experiment.
no information on what data would support or not support the hypothesis.
The question was well answered by most candidates. However, it was disappointing that
only a few indicated that the different types of seed were part of the independent variable
and many failed to indicate the need to repeat the experiment.
(b)
The field investigation needed to be carried out in the field and be feasible. Points were
deducted if it wasn’t. Points were deducted if both species were not used and there was
no comparison between areas.
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Environmental Science
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Subject Code: EVS5C
Question 3
(a)
Criticisms of the experiment:
Ethical concern: it would be unethical to put a live goldfish in acid to see how it would be
affected.
Sample size; one goldfish is not enough. A number of individuals would be required and
more than one species would be preferable.
Acid rain rarely contains hydrochloric acid.
The control is not adequate. More tanks would be needed.
(b)
Field studies:
Choose a lake affected by acid rain and measure its pH and the population and health of a
particular type of fish. Repeat this in a lake not affected by acid rain.
Field studies are less valid because of the variables that cannot be controlled.
Comments
(a)
There are a number of components missing in this experiment and any three were worth a
point each. However a point was deducted if the ethical consideration was not included.
(b)
The field investigation needed to be carried out in lakes and be feasible. Points were
deducted if it wasn’t. Points were deducted if there was no comparison between affected
and non-affected lakes or if fish were not investigated.
It was pleasing to see that most candidates recognised the ethical consideration.
Question 4
Data should be collected above and below the dam and compared. Both biotic and abiotic data
should be collected.
Abiotic data would include temperature, pH, dissolved oxygen, B.O.D., nutrients, water flow,
water depth, dissolved solids and turbidity.
Biotic data would include the presence of index species, bacteria, phytoplankton, zooplankton,
invertebrate species and fish.
Comments
Many candidates do not understand what is involved in monitoring. Monitoring includes
baseline studies, which are measurements of the present state of a system. While baseline
studies are a component of both Environmental Impact Assessments and Environmental
Management Plans, these are criterion 9 not 4.
Credit was given for feasible answers but points were deducted if there was no indication that
the studies needed to be carried out above and below the dam and that both biotic and abiotic
data needed to be collected.
Unfortunately many candidates only considered the water behind the dam and only considered
the abiotic factors.
2005 External Examination Report
Environmental Science
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Subject Code: EVS5C
Part 2 – Criterion 7
Question 5
(a)
Positive feedback. (1 mark)
Explanation: Loss of tree cover -> soil exposed to erosion (1/2 mark) (especially as this
is a hillside, with the possibility of losses through runoff)
Loss of nutrients (& soil) through erosion -> poor grass establishment; which leaves soil
exposed to further erosion & a continuing decline in soil fertility (1/2 mark)
Some candidates also argued for sheep impacts (eg compaction) as a cause of erosion, &
received credit for this – but to get full marks, it was important to take the suggested
feedback components through a full cycle, always showing the feedback effect on the
soil.
Comments
In 5a, many candidates suggested increased salinity as the only impact of tree clearing:
this seemed unlikely on a hillside, although one candidate gained credit for this
suggestion by specifying a rise in the water table at the bottom of the slope. Candidates
seemed unaware that salinity problems are specific to certain soil types and cannot be
expected as a general outcome of any tree clearing, anywhere.
(b)
Positive feedback (1 mark)
Explanation: Loss of cloud -> loss of rainfall (1/2 mark)
Loss of rainfall -> less chance of rainforest regeneration (1/2 mark)
Comment
Again, it was essential to take the reasoning ‘full circle’, by giving outcomes which could
be understood to lead to a worsening spiral, of forest damage -> less rain -> less
regeneration of/more damage to the forest -> less rain etc.
Also, it was essential to show the feedback effect ‘on the forest ecosystem’.
(c)
Positive feedback (1 mark)
Decomposition by microbes results in the release of CO2 (1/2 mark) (and, heat) as a result
of respiration
-> CO2 is a greenhouse gas, which results in further warming (1/2 mark), which leads to a
further increase in the rate of decomposition (and the heat released by microbial activity
speeds up decomposition even more).
Comment
For this question, it was essential to show the feedback effect specifically ‘on global
temperature’.
(d)
Negative feedback (1 mark)
Increased plant growth, removes CO2 from the air through photosynthesis (1/2 mark)
- thus counteracting the enhanced greenhouse effect and reducing global temperatures
(1/2 mark)
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Environmental Science
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Subject Code: EVS5C
Comments
Again, for this question, it was essential to show the feedback effect specifically ‘on
global temperature’.
A surprising number of candidates argued here that increased plant growth leads to higher
populations of animals, resulting in a higher output of CO2 and hence greater global
warming - if you scale up this thinking on a planetary scale we would all be dead, as the
earth’s plants would not be producing a sufficient excess of oxygen from their
photosynthesis to sustain animal life on earth! These candidates reverted to a more
‘conventional’ appreciation of the balance between plant and animal numbers & biomass
in their answers to Question 8, but clearly had trouble bringing their understanding of
pyramids of biomass and the carbon cycle across into Question 5.
A very few candidates still have ideas about global warming incorrectly mixed up with
thoughts about the ozone layer.
In all parts of Question 5, it was apparent that many candidates were meeting the concept
of feedback in ecosystems for the first time, or understood this very poorly. ‘Positive’ &
‘Negative feedback’ were not well understood: many candidates thought this was about
‘good outcomes’ & ‘bad outcomes’, which is not the case.
Only one candidate in the state successfully answered Question 5 with simple feedback
diagrams (only one other attempted this, less successfully). Clear feedback diagrams
would have been an excellent approach to the question, and might be worth practicing.
In all parts of Question 5, many candidates needlessly restated or expanded the
information given in the question, without going on to discuss the EFFECTS of the
situation described. Unfortunately, there were no marks for simply showing an
understanding of the given scenario, without moving on to explain the feedback effects
that would RESULT FROM the given situation.
Question 6
(a)
Half a mark each, for 3 biotic & 3 abiotic factors, up to a total of 3 marks. Where
candidates failed to specify whether factors were biotic or abiotic, the marks for the
factors given were halved.
Biotic factors:
•
•
•
•
•
Predators (cats, owls, hawks, foxes)
Insects carrying viral diseases
Availability of food plants
Nutritional quality of food plants (sodium content)
Rabbit population, influencing efficiency of cooperative burrowing
Abiotic factors:
•
•
•
Soil type
Soil moisture content
Overall climate of an area
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Environmental Science
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Subject Code: EVS5C
•
•
•
•
Rainfall
Drought
Topography (mountains vs. plains)
Obstacles to movement, eg fences
Comments
This should have been extremely easy, & most candidates did well. However, some
seemed not to know what a ‘factor’ was, & simply made statements ‘about rabbits’ (eg
‘young rabbits are easy prey for cats …’, rather than stating ‘cats …’ as a factor). This
was marked leniently, but the thinking was sloppy.
Some candidates insisted on trundling out a list of rote-learned factors, including pH and
temperature, when the stimulus material gave so many good possibilities that this was
unnecessary.
Some candidates listed as ‘factors’ statements such as, ‘an adult female may produce 20
– 25 young’. Since we were looking for factors influencing the SURVIVAL of the
rabbits, the mere fact of being born (& when breeding occurs) was not credited.
A simple table (vertical line down the space provided; heading each side; list of 3 points
under each heading) seemed to be the most sensible approach, and was used by many of
the stronger candidates.
(b)
Various ways to gain 2 marks, such as:
Southern Australia (1 mark)
- since it has a climate similar to the area where rabbits originated/evolved (1/2 mark)
- and hence rabbits are pre-adapted (or ‘already adapted’, or just ‘adapted’) for these
conditions (1/2 mark).
Or: Half a mark each for any of the following, up to a total of 2 marks:
- an area with well-drained dry ground;
& of a soil type to support good burrows;
& with reliable spring rains
- & hence plenty of feed;
& a low incidence of drought;
- in an area that is not mountainous;
- so nutritional quality of plant food is good;
& without many barriers to movement (eg fences);
- without excessively high predator numbers;
- without excessively high numbers of insects carrying viral diseases.
Comments
Many candidates mentioned specific Australian states, including Tasmania, but didn’t
always back these up with sensible reasons. For instance, it is not true to say that
Tasmania as a whole ‘isn’t wet’ or ‘isn’t mountainous’, and it is unrealistic to suggest
that soil types are suitable for rabbits across all parts of any state. The strongest
candidates used specific knowledge such as ‘sandy soils near coastal areas of Tasmania’,
‘dry soils such as in many parts of the east coast of Tasmania’. Several candidates
remembered Tasmania’s low fox numbers/fox free status, which was a good point.
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Environmental Science
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Subject Code: EVS5C
Overall, this was marked leniently, & most candidates got the 2 marks.
(c)
insects
cats
rabbits
owls
foxes
hawks
lambs
green plants, grass
3rd trophic level
or secondary consumers
or carnivores
2nd trophic level
or primary consumers
or herbivores
1st trophic level, or producers
Marking:
1 mark for arrows, showing the right connections & pointing the right way (showing
energy flow from one organism to the next) _ mark for overall layout; all organisms on
the same trophic level placed on then same level of the diagram.
1 mark for labels (any of the approaches shown above was accepted).
1.5 marks for including all the organisms named in the question (1/2 mark deducted for
any omitted organisms, until no marks left after 3 left out).
Decomposers were optional.
Comments
Overall, this was well done. Many candidates forgot the cats, owls and disease-carrying
insects. Many remembered there were insects somewhere, but turned them into herbivores
competing with the rabbits and plants. A few specified ‘mosquitoes’ on the basis of
having read 6d. A very few candidates had arrows round the wrong way; more omitted
arrow-heads altogether. A fair few candidates went for a 4th trophic level, with ingenious
foxes catching & eating owls and hawks as well as cats. Some of these suggestions were
unconvincing, but all were unnecessary, as there was enough clearly-stated information to
make a good food web without further speculation.
(d)
Predator (1 mark) because a parasite lives ‘on or in’ its host, (1 mark) whereas the
mosquito hunts the rabbit (its prey), feeds briefly on its blood, and then flies away.
Comments
The vast majority of candidates opted for ‘parasite’, which was accepted if justified using
an appropriate definition.
Question 7
Answers:
(a)
Nitrogen fixation/ nitrogen fixing (1 mark)
(b)
Nitrogen fixation/ nitrogen fixing (1 mark)
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Subject Code: EVS5C
(c)
Nitrification (1 mark)
(d)
Any 2 sensible points, for _ mark each, up to 1 mark, eg:
- nitrogen-fixing bacteria in root nodules convert atmospheric nitrogen to nitrate for plant
use
- when legumes die and decompose, nitrates are released to the soil
- bacteria in root nodules combine oxygen and nitrogen to form nitrates/other forms of
biologically available nitrogen
(e)
There is not much nitrogen in the open sea, so N nutrients for proteins are limited,
reducing plankton size. Upwelling currents bring more nitrogen for plant growth and
consequent animal growth closer to the shore, explaining fisheries in these zones.
Comments
This was an extremely disappointing question to mark.
Major problems were:
•
candidates having no idea what a ‘process’ is, and writing irrelevant statements
•
candidates copying information directly from the diagram without addressing the
questions or adding any more information.
•
total confusion between bacteria, molecules, ions and processes, randomly mixed in
answers (eg ‘legumes denitrify the bacteria’, ‘the nitric acid is forming bacteria in the
soil.’)
•
lack of knowledge of the basic processes in the Nitrogen Cycle (‘processes’ offered for
7a, b and c included, ‘bacterialfication’, ‘deionisation’, ‘combustion’, ‘photosynthesis’,
‘eutrophication’, ‘nutrefying’, ‘respiration’, ‘absorption’, ‘precipitation’, ‘secondary
succession’, ‘producing’ and more).
•
for 7e, very few candidates made the connection between nitrogen and protein; very few
understood that the producers take up inorganic nitrogen and build it up into complex
molecules such as proteins, which then pass up food chains; very few understood the
connection between fish (at the top of the food chain) and available nitrogen going into
the bottom of the food chain.
Alas! The remaining mystery is – with the Nitrogen Cycle a standard feature in textbooks, why
didn’t the candidates simply look up the answers to parts a – d?
Question 8
(a)
Trees are big, and hence one tree may have similar biomass to many small grass plants,
and support similar numbers of consumers.
(1 mark for big tree vs. small grass plant; 1 mark for one tree vs. many grass plants).
Comments
Somehow, the simplicity of this question was a problem, and not many candidates
managed to give the necessary short, simple, but complete answer.
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Environmental Science
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Subject Code: EVS5C
Many candidates pointed out that consumers on a tree (eg caterpillars) are likely to be
small whereas grassland consumers (eg wallabies) are much bigger, and hence present in
lower numbers – whilst this is true, it’s not very relevant to this question, where the
number of primary producers varied, but the number of primary, secondary & tertiary
consumers shown in the two pyramids appears to be identical.
(b)
For one mark each, two sensible points of explanation, such as:
Phytoplankton can reproduce fast & have a shorter lifespan than zooplankton.
The phytoplankton may be reproducing faster than they are being consumed by the
zooplankton. (1 mark)
- whereas the grass in a grassland cannot reproduce at such a rapid rate, so the grassland
pyramid cannot be inverted (1 mark).
Comment
Many candidates had a good understanding of the possibilities here, and explained them
well.
(c)
All three energy pyramids would have the same shape, and this would be most similar to
the pyramid of biomass for the grassland ecosystem (1 mark).
(Or the shape of such a pyramid could be described &/or simply sketched)
Or, some candidates gained credit for saying: An energy pyramid can never be inverted.
This is because approximately 90% of the energy at each trophic level is lost by the time
the next level is reached, and only around 10% of the energy in one trophic level is passed
on to the next. (1 mark)
(d)
Since 90% of energy is lost from one trophic level to the next (in the form of heat
transferred to the environment; movement, in faeces and in undigested material such as
teeth, claws, fur, feathers) (1 mark for some idea of how energy is lost)
- there would be insufficient energy remaining to sustain a higher order carnivore at much
beyond the 4th or 5th trophic level.
Comments
This was well understood and well explained by most candidates, and many got the full
two marks.
Some candidates simply referred to ‘the 10% rule’ or Laws of Thermodynamics in their
answers. This left some doubt as to what they actually understood – it is better to explain
rather than just refer to a rule or law.
One fairly common misunderstanding ran as follows: ‘at the higher trophic levels, the
consumers have to eat vast amounts to survive, due to the energy lost as heat etc.’ Quite a
number of candidates were very strong on this point, but it is surely entirely mistaken – it
is the grass-eating herbivores that must munch away solidly all day, due to the low energy
content of their fibrous food. However, the energy-rich meat eaten by carnivores allow
some of them to feast one day and rest for a week. The NUMBER & BIOMASS of
carnivores must be few, because of all the energy lost on the way up the food chain – but
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Environmental Science
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Subject Code: EVS5C
each gram of meat eaten is highly nutritious, and they do NOT have to eat vast quantities
of it.
Part 3 – Criterion 8
Question 9
(a)
The effectiveness became less after each application. The remaining population becomes
higher to the point where the population exceeds the original population level
(b)
The pesticide is selecting the pesticide resistant insects which survive. These resistant
insects multiply after each application which only kills the non-resistant insects. After the
fifth application nearly all the insects are resistant. There is a need to apply the insecticide
at increasingly frequent intervals.
Comments
Some candidates were confused between the terms ‘immunity’ and ‘natural selection’. Quite a
few candidates talked about insects gaining ‘immunity’ to the pesticide, rather than being
selected ‘for’ or ‘against’.
Question 10
All energy resources have an impact:
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Dams affect river ecology
Solar panels use other resources during production and use a lot of energy in construction
Nuclear power has nuclear waste storage, mining and tailings dams problems
Fossil fuels have mining and carbon dioxide greenhouse and acid rain and photo-chemical
smog effect problems, which could be argued to be more serious than the above.
Wind farms need to take into account bird migration, visual pollution, but with significant
energy conservation measures and education about problems – people must change
lifestyles to prevent excess energy use
What needs to be made clear is whether the environmental benefits outweigh the costs,
particularly in relation to other energy forms.
Comments
Generally very well answered. Some candidates only listed alternative energy resources, and
failed to explain any impact on the environment.
Some failed to see any benefits from soft energy pathways.
Question 11
The organisms form a food chain in which the pesticide is concentrated (bioaccumulated)
because it is persistent (not biodegradeable) and fat soluble. For each trophic level one gram
increase in growth requires 10 grams of food from the lower trophic level. All of the pesticide is
passed on resulting in greatest storage at the highest trophic levels.
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Subject Code: EVS5C
Comments
Very well answered. Majority of candidates knew about ‘bioaccumulation’. Some thought
plankton had less pesticide (0.04ppm) than birds (26.40ppm) because their body mass was
smaller.
Question 12
(a)
•
•
•
•
•
Maria Island was required to be free of disease, and no other devils would occur in that
area.
The areas near Devonport and Southport were seen to be free of the disease.
Young female devils need to be screened and monitored for a period of time.
Ability of devils to survive relocation away from their established territories.
Whether island habitat is suitable for devils and secure.
(b)
The captive breeding program would aim to establish a population of disease free devils
that are hopefully resistant to the virus. These can then be used to re-establish the
mainland population to prevent extinction of this species.
(c)
Loss of genetic diversity. The captive devils may become susceptible to other diseases and
may lose the ability to compete for food when re-introduced to the wild.
Very well answered by majority of candidates.
Question 13
(a)
Tree roots take up much of the infiltrated rainwater in the soil, preventing it from reaching
the groundwater table. This lowers the groundwater table and prevents dissolved salt from
lower in the soil profile from reaching the surface.
(b)
Irrigation adds more water to the water table because it is not being taken up by plants at
the rate it is being added. Waterlogging leaches further salts from the soil to add to the
already saline water table.
Run-off also increases salinity in rivers
Comments
Very well answered. Some candidates thought that all plants absorb salt. In most cases salt
levels are reduced by plants lowering the water table rather than accumulating salt.
Part 4 – Criterion 9
Question 14
Answer: any five points which in which the footprint is discussed.
•
Energy in the future could be based on solar, hydrogen, nuclear – where carbon dioxide is
not an issue, and the footprint of forest needed to reduce carbon dioxide does not apply.
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Subject Code: EVS5C
•
•
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•
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Train and bus (electric or hydrogen) transport could be included in the ticketing price, and
this would discourage further the use of cars which add more to the footprint.
Roads near the football park could be for bus and bicycle only; bicycles do not need
fossil fuels and thus forests for carbon dioxide.
Replace beer with water. Water does not need the land resources of beer production.
Replace chicken burgers with vegie burgers. Food lower in the food chain saves up to
90% of energy and thus incurs a lesser footprint.
Materials used in food and drink packaging could be made of recyclable materials and the
collection of this would have less of a footprint in waste disposal.
Comments
Answers which got lower marks did not discuss how the footprint was reduced, just a list of
things that could change. Other poor answers did not address the scenario given. Overall the
question was well answered.
Question 15
Answer:
(a)
•
•
•
•
•
•
•
(b)
•
•
•
Any five environmental effects Effects on flora and fauna – rare, vulnerable and endangered species – and disturbance to
the wetland.
Whether the farm is in the path of migratory birds.
Roads and transmission lines will cross remote land with landscape values; potential
effects on visual amenity.
Potential introduction of exotic pest species.
Potential effects on the recreational values of the area.
Effects of magnetic fields associated with the transmission line.
Effects of noise from the turbines.
Both Commonwealth and State legislation can be applied to this wind farm situation
because where threatened species are involved the Commonwealth EPBC Act and the
State Threatened Species Protection Act are relevant.
The Commonwealth has jurisdiction over the Ramsar Convention (wetlands) and
Migratory Bird agreements.
The State Coastal Policy is also relevant for this project.
Comments
Very often candidates wrote about EIA in a general way and did not address the question i.e.
environmental factors for the wind farm. Also, in part (b) a general answer on legislation for
Lake Pedder did not apply here (although awarded marks).
Question 16
Discuss to what extent is ………………………….followed by practices set out in the various
forestry agreements for Tasmania.
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Intergenerational Equity Contribute to by
•
Forest management plans and environmental surveys (EMP & EIS/EIA) conducted by the
forest practices board.
•
Maintenance for forest structure and diversity by varied logging coupe dispersal patterns
•
Division of the state into Bio-regions recognising the importance of regionally significant
species, and vegetation types.
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Preservation of vegetation types. i.e. reserves, conservation areas, national parks, WHA,
Convenants on private land.
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Education about the value of forests i.e. their importance commercially
•
On going forest resources for the future through sustainable management in the form of
timed rotation of plantations & regrowth, selective logging, and appropriate slash and
burn techniques.
Detract from by
•
Decrease in number of living species flora and fauna.
•
Decrease in diversity of living species flora and fauna.
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Decrease in habitat for living species flora and fauna.
•
Loss of general forest values eg habitat, aesthetics and contribution to environmental
maintenance.
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Increase the degree of threat to already threatened flora and fauna.
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Loss of cultural heritage.
•
Inappropriate management of animals in regenerating forest or plantation e.g. 1080
Intra-generational (Social) Equity Contribute to by
•
Tourism
•
Preservation of vegetation types and areas containing threatened species. ie reserves,
conservation areas, national parks, WHA.
•
Increased employment – through forest workers, agriculture, tourism
•
Increased access to forest areas roads and even use of resource
•
Increase in research and funding.
•
Maintaining diversity of vegetation types through timed logging rotations and burning
practices
Detract from by
•
Decrease in number of living species flora and fauna.
•
Decrease in diversity of living species flora and fauna.
•
Decrease in habitat for living species flora and fauna.
•
Loss of general forest values eg habitat, aesthetics and contribution to environmental
maintenance.
•
Increase the degree of threat to already threatened flora and fauna
•
Loss of personal places that can be integral to ones identity.
•
Loss of cultural heritage.
•
Loss of possible farmland and options for agriculture.
•
Inappropriate management of animals in regenerating forest or plantation e.g. 1080
•
Conservation of Biodiversity and Ecological Integrity Contribute to by
•
Preservation of vegetation types and areas containing threatened species. ie reserves,
conservation areas, national parks, WHA.
•
Create plantation forest to reduce the need for logging of natural forest.
•
Increase in research and funding.
•
Forest management plans and environmental surveys (EMP & EIS/EIA) conducted by the
Forest Practices Board.
•
Continuous environmental monitoring.
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Environmental Science
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Subject Code: EVS5C
•
Division of the state into bioregions and recognition of regional significance.
Detract from by
•
Decrease in number of living species flora and fauna.
•
Decrease in diversity of living species flora and fauna.
•
Decrease in habitat for living species flora and fauna.
•
Loss of general forest values eg habitat, aesthetics and contribution to environmental
maintenance.
•
Increase the degree of threat to already threatened flora and fauna
•
Loss of personal places that can be integral to ones identity.
•
Loss of cultural heritage.
•
No compensation for the loss of animal habitat.
•
Inappropriate management of animals in regenerating forest or plantation e.g. 1080
Precautionary and Anticipatory Principles Contribute to by
•
Forest management plans and environmental surveys (EMP & EIS/EIA) conducted by the
forest practices board.
•
Continuous environmental monitoring, acquisition of baseline data.
•
Preservation of buffer zones around rivers, threatened species sites and vulnerable areas.
•
Leaving a set % of each forest type based on Pre-European distribution of vegetation
communities.
•
Regeneration
Detracts from by
•
Old growth forest which can not be regenerated in an acceptable time frame.
•
Inadequate surveying of coupes.
•
Inadequate base line data
•
Destruction of endangered species habitat.
•
Inappropriate management of animals in regenerating forest or plantation e.g. 1080
Pricing environmental and natural resources (‘user-pays’ principle) Contribute to by
•
Taxation
•
Charging more for less readily available and specialty timbers.
Detracts from by
•
Under charging for forest products
•
Not taking into account all aspects of the cost to the environment. Air, Water, Land
•
Not taking into account all the benefits of the forest that people value i.e. social, aesthetic
and spiritual.
•
No compensation for the loss of animal habitat.
Efficiency of resource use Contributes to by
•
Wood chips (Pulp)
•
Veneer timber
•
Construction timber
•
Various types of paper
•
Saw logs
•
Craft wood
•
Replanting
Detracts from by
•
Rate of use
•
Rate of logging
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Environmental Science
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Subject Code: EVS5C
•
Inappropriate uses of various wood types i.e. craft wood for woodchips.
Comments
Each of the three principles chosen had the potential to gain 4 marks.
Candidates were awarded marks for discussing the various ways each selected principle was or
was not followed by forest management in Tasmania (and hence followed by the various
forestry agreements established in Tasmania.)
A general reliance on regurgitation of information from notes, rather than a true understanding
of the concept was the major down fall of most candidates in this question.
The question was to discuss to what extent ‘the selected sustainability principle’ is followed by
practices set out in the various forestry agreements for Tasmania.
Many candidates failed to realise this and simple wrote definitions of the principle or did not
refer to forestry at all. For this they received no marks.
Many candidates wrote why they should follow the principles of ecological sustainable
development, not how or to what extent it is followed by forestry in Tasmania. Depending on
how this was done they received minimal marks.
Answers often only referred to one way in which forestry managed the chosen principle and
hence only one mark was awarded. e.g. ‘They don’t manage it because they chop down old
growth.’
May references were made to old growth forests with no reference to the exact value of them.
Answers were constrained by one sidedness, severe personal bias and significant narrow
mindedness throughout all principles.
Many mistakes were made through a misunderstanding in the difference between principles e.g.
Inter and Intra – generational.
In general candidates did poorly on this question due to not reading/answering the question
properly and an enormous reliance on copying information rather than the understanding of
concepts.
Candidates should beware of overstatements such as, ‘It will destroy the
environment’.
Part 5 – Criterion 10
Question 17
(a)
(b)
(c)
Westerly
Southerly
Melbourne; The CO2 levels were highest on the days when a northerly wind was blowing
from Melbourne, elevating measured CO2 levels.
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Environmental Science
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Subject Code: EVS5C
(d)
Its location allows for collection of global/Southern hemisphere base-line gas data due to
its latitude (‘roaring 40’s’) and remoteness from westerly landfall
Comments
This question was generally well answered in parts a, b, and c. ‘Easterly’ was also generously
marked as correct for part (b) as it did not once appear as a wind direction in the data.
Many candidates seemed not to know the true purpose of the Cape Grim station and thought it
was to measure pollution from Melbourne, Hobart and Launceston.
Question 18
(a)
(b)
(c)
Increasing levels of ozone result in less survival in plants at the end of the trial, ie, more
ozone, less plant survival
Ozone; when comparing trial 4 and 5 when both gases are at 1.0 ppm, 17 plants survived
in the ozone trial, compared to all 50 surviving the same concentration of sulphur dioxide.
The combined effects of both the ozone and sulphur dioxide had the least plants surviving
and the overall effect was more lethal than each of the gases alone.
Comments
This question was attempted by all candidates with the majority correct for sections (a) and (b).
In part (c), many candidates did not explain the results, and fell into the trap of describing the
results instead.
Question 19
(a)
(b)
(c)
2/20 = 10% of days unsafe
10 days
Seepage from septic tanks, release of partially/untreated sewage, flushing drains from
increase in stormwater levels (any one of these)
Comments
This question was well answered by a majority of candidates. Candidates erred by
miscalculating a simple percentage, or also giving the answer to part (b) as a percentage.
Some candidates ruled lines on their graph to make the data easier to interpret, which was
pleasing to note.
Question 20
(a)
Agricultural run-off from farm fertilizers has a cumulative effect as the concentrations
increase downstream as more agricultural areas contribute to the nitrogen and phosphorus
load.
(b)
Farm erosion from overgrazing, cleared paddocks, stock disturbance or poor farming
techniques increased the suspended solids (SS), eg soil load along the catchment as it
passed through more agricultural areas and picked up SS loads from tributaries.
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Environmental Science
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Subject Code: EVS5C
(c)
Clean water fauna (fly larvae and nymphs) cannot tolerate the increasing pollution levels
(N, P and SS) and their numbers decline downstream. Index species are more tolerant of
poor water quality (Chironomus, Tubifex) increase in number downstream.
(d)
Nitrogen and phosphorus from agricultural run-off creates eutrophic conditions in the
bay. Algal growth is stimulated, hence the bloom.
(e)
As the levels of phytoplankton (as stated) were insignificant in the river, so will be the
distribution of zooplankton, which feed on phytoplankton; numbers will be low due to
very limited food supply.
(f)
B.O.D. is highest in the bay as decomposer organisms require very high levels of D.O. to
break down the algal bloom present, hence increasing the B.O.D.
Comments
Most candidates answered the start of this section well, but tended to err on parts (e) and (f).
Candidates in part (c) tended to write the Chironomids/Tubifex ‘liked pollution’ or even ‘ate the
algae’ rather than being index species and quite tolerant of poor water quality.
Most candidates did not connect eutrophication from N and P in section (a) with creating
conditions ideal for algal growth in part (d). For part (e), most candidates did not answer the
question well and seemed to miss the stating of low phytoplankton numbers in the background
information in the question. Some also wrote that both species were marine organisms only and
so would only be found in the bay.
In part (f), many candidates seemed to confuse D.O. (Dissolved Oxygen) with B.O.D.
(Biochemical Oxygen Demand) or could not demonstrate within the context of the question and
provide sufficient explanation of why B.O.D. was highest in the bay.
All correspondence should be addressed to:
Tasmanian Qualifications Authority
PO Box 147, Sandy Bay 7006
Ph: (03) 6233 6364 Fax: (03) 6224 0175
Email: [email protected]
Internet: http://www.tqa.tas.gov.au
2005 External Examination Report