Download EV846 Environmental Science

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EV846
Environmental Science
A S S E S S M E N T
B O A R D
2002 External Examination Report
General Comments
The feedback from teachers and candidates indicated that the examination paper covered the syllabus and was well
received.
Criteria 6, 8 and 9 were the most difficult criteria for candidates. Many candidates did not relate their answers to
the actual question and simply copied information from their notes about the topic.
Many candidates had difficulty completing the paper (they answered only one question in Section B Criterion 9)
and unfortunately there are still a few candidates answering all three questions and consequently disadvantaging
themselves by having less time to fully answer questions. The degree of difficulty for each question within a
criterion in Section B varied which may have forced candidates to answer questions they had not studied.
Overall, the exam gave candidates the opportunity to display their environmental knowledge and understanding
and to be rewarded accordingly.
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.
Section A
Comments - Criterion 4
This section was generally well answered with 15% of candidates getting less than 10 out of 20. Very few
candidates got less than 7. The average and median mark was 13 and the mode 12.
Question 1
(a)
Toothed whales
(b)
Composition of organic material and the release inorganic nutrients. Production of organic material via
photosynthesis (or chemosynthesis)
(c)
Any 6 interconnected species from the Antarctic marine food web.
(d)
Loss of energy at each trophic level means insufficient energy to support more than 5 trophic levels.
Around 90% of available energy lost at each trophic level from metabolic processes, heat, movement,
faeces production etc.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
(e)
Krill are the primary or sole food source of Crabeater seals and Adelie penguins, and account for half the
food source of the Emperor penguins and Baleen whales. Any reduction in krill numbers will impact on
the numbers of penguins and seals (which are in turn the main food source for the Leopard seals) and on
Baleen whales. A reduction in Crabeater seal biomass will result in Leopard seals relying on alternative
food sources (Adelie and Emperor penguins and krill). Consequently the reduction of large numbers of
krill will have the greater effect on the rest of the food web.
Comments:
Some candidates did not answer Question 1 (a). The most common incorrect answer was Baleen Whales.
Questions 1(b and c) were well answered, whilst 1(d) was very poorly answered, with many candidates
demonstrating little understanding of energy loss up trophic levels. Some candidates in Q1(b) did not use the
food web given from which to draw a food chain. Credit was given for reasonable attempts. Q 1(e) was quite
well answered, although many did not give enough information for 3 marks. Many stated that krill was the
correct answer and gave good reasons but did not mention crabeater seals.
Question 2
Natural ecosystem
Permaculture
Main inputs
Sunlight, water,
oxygen, carbon dioxide,
trace elements.
Sunlight, water,
oxygen, carbon dioxide,
organic matter.
Main outputs
Heat, water, oxygen,
carbon dioxide, organic
matter.
Heat, water, oxygen,
carbon dioxide, organic
matter.
Amount of recycling
Species diversity
Complexity of food
web
High
High
High
Moderate
Moderate
Moderate
Conventional
agriculture
Sunlight, water,
oxygen, carbon dioxide,
artificial fertilizer, trace
elements, pesticides,
herbicides,
Heat, water, oxygen,
carbon dioxide, organic
matter, chemical
residues.
Low
Low
Low
Comments:
Question 2 proved to be easy for the majority of candidates, although several did not put pen to paper! Answers
demonstrated a good understanding of the issues, with a large number of candidates getting 5 or 6 marks out of
6.
Question 3
The number of bird species increase with the complexity of the ecosystem. Grasslands provide limited habitats
for birds and climatic conditions relative to mixed forest are extreme. Mixed forest provides the the greatest
variety of food, shelter, protection and nesting sites for both ground and tree nesting species, given that the
mixed forest shows extensive understory including shrub and grassland beneath the mature canopy of trees. There
are more ecological niche options in the mixed forest than the grassland habitat.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Comments:
Once again, Question 3 was well answered by the majority of candidates. The best answers mentioned biological
diversity and the concept of an ecological niche. Most were able to state the relationship (1 mark) but fewer were
able to explain the link.
Question 4
(a)
ß
ß
ß
Initial exposure to pyrethrum killed approx 90% of insects
Within the population there were individuals resistant to the pyrethrum who survived
The resistant insects bred mainly resistant progeny and the population increased exponentially until
another limiting factor decreased the population growth rate
(b)
Any 2 of:
ß
Increasing numbers of pesticide resistant insects
ß
Non-target and/or natural predators killed
ß
Some pesticides are residual in waterways and soil
ß
Potential for pesticide to be biomagnified up a food chain
(c )
Any 2 of:
ß
Increased breeding of natural predators by some means
ß
Smaller crop areas with shelter belts for natural predators to inhabit
ß
Introduction of permaculture techniques
ß
Companion planting of crops to deter insects
ß
Use of chemicals such as garlic, urine etc to deter insects
ß
Use of/introduction of a biological control predator
ß
Use of/introduction of an insect pathogen such as a virus, fungus or bacteria
ß
Genetically modified insect resistant crop
ß
Breeding program of sterile male insects to reduce population
ß
Mechanical services eg nets
ß
Physical capture devices
ß
Pheromone based attractant traps
Comments:
(a)
Most candidates showed ability to analyse graph quantitatively. Few understood concept of immunity or
resistance being a genetic predisposition of a percentage of the population and that the resistant few then
reproduced passing in many cases, this resistance on to their progeny. Most candidates incorrectly
suggested that resistance was gradually acquired through continual exposure; as an adaptation. Concept of
natural selection not well understood.
(b)
Concepts of biomagnification/accumulation well understood although most candidates view all
conventional chemical pesticides as being non biodegradable and very residual in soil and water which is
not so. Generally well answered.
(c)
Many candidates described use of an organic pesticide but were confused about what the term organic
means. Terms such as ‘natural pesticide’ and ‘eco-friendly’ pesticide were also used with little theoretical
knowledge.
Generally well answered.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Question 5
(a)
•
•
•
Reduction in native species numbers due to predation by fox
Competition for food between fox and native predators eg quoll, devil reducing native species numbers
Introduction of diseases into native animal population
(b)
1080 in baits has the potential to kill native species which consume it as well as foxes
(c )
The bounty would lead to further illegal import of foxes (live, dead or remains) into Tasmania to collect
bounty. Also indiscriminate hunting and potential environmental damage.
The rewards will act as an incentive to the public to inform on people responsible for the fox importing
and a disincentive to others to try.
Apprehending the people may lead to information about released foxes age, sex and numbers plus date and
site of release.
Comments:
(a)
Basic ideas on main dangers of foxes to Tas ecology were sound but many candidates were vague about
outcomes using terms such as ‘threaten’, ‘harm’, ‘destroy’ and ‘affect’ rather than more precise terms
indicating predation, competition, population reduction etc. Most candidates showed some knowledge of
interaction in a predation and competition scenario between an introduced species and endemic species.
(b)
Most candidates simply stated that 1080 would be inadvertently eaten by native animals or pets, with
limited knowledge of the use and potential problems of 1080.
(c )
The major reason for a bounty being unwise was recognised by nearly all candidates but most were unable
to give specific reasons why catching the culprits and gaining information from them was so important.
Many candidates simply thought the conviction/apprehension of the culprits was good for retribution
reasons.
Question 6
(a)
•
•
•
•
•
•
•
•
•
•
•
•
•
Any 4 of:
Global increase in deforestation
Over fishing
Global increase in greenhouse gas production
Global increase in fossil fuel usage
Global increase in urbanisation
Global increase in population of humans
Unsustainable agricultural practices eg use of fertilisers, pesticides, herbicides
Global increase in land degradation through nutrient depletion and irrigation mismanagement
Global increase of mining of noon-renewable mineral resources
Use of ozone depleting chemicals such as CFCs
Burning of fossil fuels containing high levels of impurities which result in acid rain
Mismanagement and overuse of freshwater
Agricultural expansion into forest biomes
(b)
Use one of the above:
2 reasons why the problem has developed
2 long term effects if the problem remains unchecked
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Comments:
(a)
Generally well done question except some candidates identified the global problem rather than the
unsustainable practice which lead to the problem.
(b)
Candidates were better able to identify 2 or more long term effects than they were able to identify the
cause/s of the problem they were discussing. Better candidates identified ecological and social issues
which lead to the problem.
Criterion 6
Question 7
(a)
The precautionary principle involves shifting the burden of proof to the proponents of an activity to
prove sustainable development rather than to opponents to prove unsustainable outcomes. It involves
risk analysis, wide consultation, scientific base line studies, exploration of alternatives, continuous
environmental monitoring.
Candidates needed to demonstrate some basic understanding of the Precautionary Principle by giving t w o
examples of the above in the context of the Aral Sea e.g: planting variety crops not just one, continuous
monitoring sea and salt levels, avoiding large scale environmental change, evaluating risk by
investigating similar situations elsewhere, cost benefit analysis, proper initial research, EIS.
(b)
1.
Legal management: any three of:
Appropriate laws and policies eg on water irrigation quotas, fishing quotas, fishing management,
sustainable development, land use planning/zoning, coastal protection, participation in international
treaties for protection coast lines
2.
Economic management: any three of:
cost/benefit analysis, taxes and royalties on water use, licence fees, encouraging more diverse income
streams from other areas such as tourism, user pays principle, placing tangible $ values on
environmental assets, tax incentives to save water
(c)
Intergenerational equity implies sustaining environmental and social values for future generations.
Candidates needed to discuss four values in the context of the Queenstown example eg water quality,
forest values, employment (lost opportunities as well as those created short term), community and
species biodiversity in the area, financial burden for cleanup passed to following generations, aesthetic
values of area, aboriginal values.
Comments:
(a)
Many candidates failed to demonstrate a knowledge of the ‘Precautionary Principle’. The ‘Precautionary
Principle’ is a key idea specifically referred to in the syllabus. Through intelligent guess work candidates
came up with examples of how it could operate.
(b)
Candidates who did badly on this question failed to address the two key points actually asked, namely
explain management from a legal and an economic point of view. No marks were given for explaining
possible technological or educational solutions.
(c)
Generally well answered. Intergenerational equity is a key idea specifically mentioned in the syllabus.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Question 8
(a)
Discuss any three of:
Management issues such as lack research and knowledge, over emotional and political decision making,
lack continuous monitoring, lack visionary management plan. Other physical factors such as protection
from fire, removal competitors and predators, loss ecological balance, exponential growth on removal of
limiting factors on carrying capacity, lack emigration corridors when over crowding occurs.
(b)
Candidates need to discuss two issues from each proposed solution such as:
1.
Sterilising and relocating/culling:
Difficulties of dealing with national icon in this way - sentiment
Short term solution before problem re-establishes
Lack genetic variation in small separated colonies
Expensive veterinary procedures
Stressful on animals
Image and marketing problem esp for tourism
Advantage of fast response
2.
Replanting suitable trees with wild life corridors:
Advantage of also restoring other forest values simultaneously
More natural ecologically balanced procedure
Slow to take effect
Maintains large gene pool for future generations
Requires adequate areas of suitable land – cost factor
A combination of both is probably best to provide short term as well as long term solutions.
Comments:
(a)
Generally well answered though most candidates concentrated on the actual physical reasons (lack
predators, abundance food etc) rather that lack appropriate management procedures (eg research,
monitoring etc.
(b)
Generally well. Few marks were given for over emotional answers along the lines of ‘what right have we
got to kill these lovely animals’.
Criterion 8
Question 9
(a)
Developing countries borrow money from the WB/IMF to increase the standard of living and
services/infrastructure/industrialization/military spending/ and with high interest rates /devaluing of their
resources/exports, they ware unable to afford loan repayments, so are in ever increasing debt.
A very high percentage of candidates attempted this question, and answered this question well. Some
found it difficult explaining what the loan was for, or how the debt increased.
(b)
Countries have been forced to exploit their natural resources/natural capital (forests, minerals)/grow cash
crops and sell at low prices/higher than renewal rate/that may be finite. Both the resource and money
leaves the country, with long-term consequences.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Most candidates answered this question well. Many candidates wrote of cash crops such as coffee, rubber,
banana and sugar, and selling of forest wood from Brazil, the Solomons and Costa. Rica. Some did not
supply examples, thus not being awarded full marks.
(c)
Problems such as famine and malnutrition from exporting food crops leaving the country starving, no
money for services such as welfare/schools or education/provision of health services, clean
water/housing/employment/child labour/rising divisions between the country's rich and poor (inequitable
wealth distribution), social and/or political unrest leading to uprisings/coup/civil war.
Most candidates were able to supply reasonable responses here. A concerning number of candidates gave
answers such as 'terrorism, hate of another country'. It was felt there were far better responses than these,
so these answers were awarded no marks.
Question 10
There were a variety of answers to this question depending which contexts (a, b, c or d) were referred to in the
response.
(a)
Different values of stakeholders (professional fisherman, recreational fisherman, conservationists and state
government), implications for local economy, conflict of interest by different user groups. incompatible
resource, use by different groups.
(b)
Seen as an unfair burden by manufacturers/suppliers of resource, causes price rises, public pay more for
goods, consumer backlash, economic hardship/strain.
(c)
Benefits investors, denies other stakeholders opportunity to debate issue and get information from other
interest groups, seen as autocratic/undemocratic as it removes right of reply, causes mistrust in
legislators, with implications at election time, can be cheaper to fast-track in terms of time and money.
(d)
Politicians are under pressure to tow party line/ satisfy electorate and may not always make the 'hard'
long-term decisions. Economic progresslunemployment figures still seen as dominant value, voters want
to see this improve, sometimes at the expense of the environment Political terms are short, often not
long enough for the benefits of long-term plans to be realized. Politician may lose scat some. voters may
not appreciate the nature of long-term environmental decisions.
Most candidates answered this question satisfactorily, with each significant, relevant point being awarded a mark.
Many candidates did not refer to at least two the contexts, hence were not given full marks.
Question 11
Zoos and captive breeding programs can be seen as a social benefit/positive externality that can fund valuable
efforts to maintain viable species numbers and gives the public a chance to view/be educated about the animal.
They are, however, not very successful with only a small percentage of the animals being successfully
re-introduced to the wild. Restoration of the native habitat is more economically sound as it is a much cheaper
option, may have benefits for other organisms in the region/ integrity of environment/ biodiversity and address
the real problem as to why the species in endangered. Native habitat restoration will not allow as many people
to view the animals and loss of habitat due to agriculture/settlement 1 poaching could be very difficult to
overcome.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Most candidates were able to discuss the costs and benefits of each approach well, as well as write which was
more desirable in term of addressing the environmental problems. Unfortunately, some candidates began a
discourse on why zoos were cruel, unnatural, etc., instead of answering the question. Some candidates tried to
answer this in the form of a cost-benefit analysis grid, missing the focus of the question, and neglected the
second part of the question.
Criterion 9
Question 12
(a)
Chemical extracts from eelgrass inhibit/reduce/prevent algal fouling of boat hulls.
(b)
Investigation 1 allows the effectiveness of chemical extracts to be assessed by controlling all the
variables. A reduction or inhibition in algal growth can therefore be attributed to the extract and no other
factor.
or
Investigation 1 keeps the effects of the eelgrass extract in the laboratory
environmental effects.
should there be any adverse
Investigation 2 allows assessment of the extract in situ, where many unknown variables could affect the
inhibiting effect of the extract. The advantage here is that the extract is being tested in the environment
for which it was designed.
(c)
The extract could be tested on other species (non-target) in the laboratory to investigate any evidence of
physiological effect. It would require exposing organisms over varying duration. If there is no evidence of
adverse impact, then an in situ assessment could be run. The diversity of the community in the
surrounding habitat should be monitored for change. Tissue residue in organisms could be monitored for
bioaccumulation.
or
A description of a fully controlled experiment could be outlined. For example two tanks with all
variables controlled and sufficient numbers of each species to simulate the natural aquatic environment
could be set up. Eelgrass extract would be added to one tank. Organisms would be monitored for
numbers, growth, health for a period of about six months and the two tanks compared.
Comments:
(a)
Most candidates could put forward an hypothesis in an appropriate format.
(b)
Mostly well answered. Marks were lost for unclear/bald answers.
(c)
This part of the question was where marks were lost, some candidates not answering it at all. Some did
not read the question carefully enough and described an experiment to test the hypothesis in (a).Testing
the extract straight into the environment without some trialing of it in the laboratory first or else in a
small enclosed area caused some loss in marks. The word “extract” was not understood by some
candidates who wrote as if it was a living organism.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Question 13
(a)
Methane from agriculture comprises 54% of total emissions but as methane comprises only 23% of the
greenhouse gas emissions, methane from agriculture contributes only 12.5% in total.
(b)
No, figures are given for methane only not sources of the other greenhouse gases. A major proportion of
CO2 emissions will come from energy and industry and CO2 makes up 73% of greenhouse gas
emissions.
Comments:
(a)
Marks were not deducted for not stating 12.5% contribution to greenhouse gases by agricultural methane.
However quite a few candidates only referred to Chart 11
(b)
Mostly well answered except for some candidates who did not refer to the graphs or else only Chart 11
and therefore concluded inaccurately.
Question 14
(a)
Risk assessment: necessary to establish the likelihood of degradation and the severity of impact.
Baseline study: necessary to establish the environmental conditions of the site, the habitats and
populations present, and how the particular ecosystem functions.
or
EIA: assesses the likely impacts on the environment of the airstrip and invites public consultation to
help decision-making.
(b)
ß
ß
ß
ß
ß
ß
Waste disposal – estimate the amount of human waste generated per person on a flight and in airports and
extrapolate that to the estimated number of visitors – all biological waste would have to be flown out
again.
Pollution control – estimate runoffs of oils, aviation fuels etc that are generated at a normal airstrip and
calculate the economic cost of removal of all spillage.
Noise pollution – investigate the impact of excessive noise on nesting/mating behaviour etc of penguins
and seals.
Habitat loss – calculate the potential loss of in area to animals for breeding/resting/migration path
interruption.
Energy usage – calculate the energy requirements for lighting and heating of buildings
Associated with visitors and calculate the economic costs associated with it.
Comments:
(a)
Cost benefit analysis was accepted if explained appropriately. A few candidates did not know the
“techniques” and wrote about measuring which was part of (b)
(b)
This was poorly answered with quite a few candidates simply copying out there notes on EIA without
reference to an airstrip in Antarctica and therefore including non-existent aspects to be considered. Many
neglected the second part of the question which asked for recommended ways of measuring the particular
consideration. If cost benefit analysis was chosen in (a), there was discussion more on economics than
the environmental impacts. Answers that actually referred to the Antarctic environment were rewarded.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Section B
Criterion 4
Question 15
(a)
Potential Energy. Energy something has because of where it is or what it is. Stored energy. Example.
The energy stored in the battery.
Kinetic energy. The energy something has that is in motion. Example – the moving car.
(b)
The chemical energy in the battery is converted into electrical energy which is used to split water into
hydrogen and oxygen. The hydrogen is then combined with oxygen in the engine of the car to produce
water . Energy stored in the hydrogen is released to provide the energy necessary to cause the car to
move. This is consistent with the First Law of Thermodynamics.
Energy is not being created or destroyed, just changed from one form to another. The motion of the car
would be used to recharge the battery. However, according the Second Law of Thermodynamics energy
conversion always result in some of the energy being converted into heat. Due to the heat produced by
the engine and friction, the motion of the car could never completely recharge the battery. Additional
energy would be required by continually replacing the battery or at least recharging it. Therefore, while
the energy may be cheaper than petrol it is not free.
Comments:
Almost all the candidates got full marks for part (a). Few candidates demonstrated an understanding of the energy
laws or energy conversions. Many wrote long paragraphs expressing concern that such cars would deplete all the
water on the planet or that water would become as expensive as petrol.
Question 16
(a)
Western Tas
Eastern Tas.
Wet Sclerophyll
Dry Sclerophyll
Tall Eucalypts with an
understorey of rainforest
Eucalypts with smaller
trees and an understorey of
heath plants or grass
Cool and Wet
Warmer and drier
Fire 40 - 100 years
Fire 7 - 10 years
(b)
Higher rainfall, lower evaporation rates, better soil, less fire, more competition for light. (any two of
these)
(c)
More resistant to frost, cloned to grow faster, less damage by insects, better adapted to the climate. (any
two)
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
Comments:
(a)
(c)
and (b) well answered.
Some confusion about what was being asked. Many answers only considered the differences between
plantations and natural forests.
Question 17
(a)
1. BOD The amount of oxygen necessary for all of the oxygen requiring processes to be carried on. If
the demand exceed the supply. Aerobic organisms may die.
2. DO. Oxygen is dissolved in water as a result of turbulence or by photosynthetic organisms. It is
used by all aerobic organisms to carry on respiration.
3. Nutrients are released from organic substance during decay or washed into waterways from forests or
farms. Too few nutrients limits food production. Too many leads to algal blooms and can be toxic to
some species.
4. Temperature depends of the air temperature and depth of the water. Heat can be a form of pollution.
Temperature affects the solubility of gases such as oxygen or carbon dioxide and the breeding cycles of
animals. Many species have specific temperature requirements.
5. Salinity. The level of dissolved salt compounds in the water. Many species are adapted to certain
levels. Too much or too little interferes with the organisms ability to maintain correct water balances.
6. pH. A measure of the concentration of hydrogen ions. Neutral is 7 on the scale of 1 - 14. Too low
and the water may become too acid, too high and it may become too alkaline. Too high to too low may
physically damage the organism and may prevent the absorption of important substances and prevent
enzymes working efficiently. (any two of the above)
(b)
HEADWATERS OF RIVER
Temperature low due to altitude, melting of snow. DO level high if flow is rapid and turbulence occurs.
BOD low as amount of organic material is low. pH - neutral as pollution level are low. Salinity low salt compounds haven't affected the water. (any two of above - other answers also considered)
MOUTH OF ESTUARY
Temperature higher as water has had time to absorb more heat. More pollution and decomposition BOD
high as more organic materials have washed in. Sewage may have been dumped in the water. DO.
probably lower. BOD higher, water warmer, not flowing as fast. Salinity levels higher from mixing
with seawater. pH could be higher or lower as a result of pollution. (any two of the above - other
answers also considered)
Comments:
This question was answered well by almost all of the candidates with many gaining all 8 marks
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
12
Environmental Science
Question 18
Some radioactive materials have half-life values of more than a million years, moaning they are persistent in the
environment and extremely dangerous for centuries. Fallout can cover in excess of 150 km, so radioisotopes em
become widespread in the environment, If liquid, the material can make its way into groundwater/rivers, or taken
up by plants. Either of these, routes results in consumption/direct exposure to reactive material
Spent fuel is often more dangerous than the original fuel, emitting alpha, beta and gamma radiation.
Radioisotopes can easily be absorbed, inhaled or ingested by animals, including humans, causing death, cancers
and tumours. Radioisotopes absorbed by plants or ingested by grazing animals are passed along the food chain
and biomagnified at each trophic level, causing long-term problems.
Most candidates answered this question satisfactorily, but most candidates wrote about biomagnification in
general, rather than the specifics of radioactive substances and their peculiar problems. It was as if the examiner
could have been reading about any biomagnified substances, not specifically radioactive ones, as the focus of the
question was lost.
Question 19
Wildfires are likely to be more extensive, last over a longer period, bum a lot hotter than controlled bums, may
bum epicormic buds, and burn up to the canopy. The forest will take a long time to recover to its pro-bum state.
Controlled burns bum only lower forest floor 'fuel', may cause re-seeding of fire-reliant species, are a lot smaller
in area, and the forest will recover much more quickly.
Most candidates answered this question well. Some candidates included information on impact on residential
areas, stock losses and number of animals affected, but this was not seen as relevant to the specifics of the
question.
Question 20
There were a number of answers here, depending if candidates answered about environmental threat 1, 2, 3, or 4.
(1)
Oil spill - Oil on the surface. inhibits light penetration, reducing photosynthesis. - Oil contains metals
and chemicals (e.g. PAH's) which are toxic to aquatic organisms, causing stress, illness or death - Oil
sticks to skin and feathers, causing birds to develop hypothermia, as they are no longer insulated - Oil
takes a long time to degrade and PAH's may accumulate in the food chain, causing illness/death to higher
order consumers - Death of many organisms will severely disrupt local food chains and decrease
biodiversity.
(2)
Sediment load
- Nitrogen in sediments may cause eutrophication, which in turn causes algae 1 dinoflagellate blooms,
which causes illness/death of consumers, and a serious decline in water quality
-Sediments increase turbidity, reducing photosynthesis for producers
- Silt and heavy metals settle on corals, smothering them, and reducing photosynthesis
- Heavy metals may be toxic and inhibit growth and reproduction of organisms, and may also biomagnify
in food chains, affecting higher order consumers.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
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Environmental Science
(3)
Fish kills
- Severe reduction in non-commercial by-catch species numbers, disrupting food chains and upsetting
local ecology
- Attraction of predators and scavengers to the area (gulls, sharks) which could also disrupt food chains
and local ecology
Decline in water quality and increase in bacteria due to large numbers of rotting fish
Decline in biodiversity in area due to fishing, of both target and non-target species
Coral bleaching
- Coral is killed due to rising temperatures associated with the EI Nino weather phenomenon and general
warming of the world's oceans due to the enhanced greenhouse effect. Coral are very temperature sensitive
and differences of 1oC may kill them.
- When coral dies, it becomes brittle and snaps - reef organisms may suffer habitat loss and the reef itself
may decline in area over time
- Organisms which feed on coral organisms may be without food, destabilizing food webs with
consequences for higher order consumers
- Symbiotic algae, zooxanthellae, may die, resulting in the death of an important producer, affecting reef
productivity and food webs
- Coral death and collapse may not protect areas from heavy seas, affecting turbidity and breaking more
coral, leading to habitat loss for reef organisms.
Most candidates were able to answer this section well. Candidates seemed to be able to give better responses to
event 1,2 and 3 rather than four. Unfortunately some candidates gave answers including impacts an local
economics, tourism and the fishing industry, but these were not seen as relevant given the specific of the
question asking for impacts on the reef environment.
Question 21
The Australian Government through its Greenhouse Office (www.greenhouse.gov.au) has allocated money for:
•
•
•
•
•
A national emissions trading scheme- carbon emissions permits will be bought and sold in an attempt to
lower overall carbon emissions to meet requirements of the Kyoto Protocol.
Crediting carbon with plantation forest sinks. Photosynthesizing forests will lower carbon dioxide levels.
Industries which buy/plant forests are given carbon credits which they can use for emissions or sell.
New technologies such as hot dry rocks, photovoltaics, wind turbines, a replacement for the lead acid
battery, and municipal waste (e.g. methane gas) projects.
Promoting energy efficiency- e.g. minimum energy performance standards for refrigerators, electric water
heaters, electric motors, lighting and air conditioners. Also promoting energy efficient housing including
passive solar heating.
Conversion of vehicles to CNG and LPG which is 50% cheaper to run and has 18% fewer greenhouse gas
emissions.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
14
Environmental Science
Many candidates rewrote green economics notes without explaining how they would reduce greenhouse gas
emissions.
Question 22
(a)
Biodiversity includes not only species but the genes they contain and their ecosystems as well. So a range
of forests will have not only different species, but genetic diversity within species and diversity of
ecosystems.
Many candidates thought the question was about the values of biodiversity.
(b)
The main processes protecting biodiversity are the Regional Forest Agreement and the Forest Practices
Code.
From an environmental perspective, the RFAs require land management strategies that satisfy the
following criteria:
•
•
•
•
•
•
Conserve 15% of pre-1750 biodiversity of vegetationtypes.
Conserve 60% of old-growth forest and 100% where it is depleted.
Protect rare and endangered species
Reserved areas to be large enough to sustain ecosystems and populations.
The reserve system should sample the full range of biological variation.
Preserve 90% of high quality wilderness areas.
Progress needs to be made in the reservation of vegetation types, old growth forest communities, and rare
and endangered ecosystems.
The Forest Practices Code is designed to take into account environmental values such as soils, water
quality and flora and fauna, all of which are important for biodiversity. Timber harvesting plans must
include streamside reserves to protect water quality, animal corridors so that animals can escape a clear
felled coupe, and reserves to protect endangered species e.g. the wedge-tailed eagle.
Practices could be improved by eliminating logging in streamside reserves, more prosecutions for
violations of the Code e.g. felling logs across streams, and more protection of old growth forest
communities.
Many answers which indicated RFA and FPC did not focus on biodiversity, but included a range of other
factors covered by the RFA and the FPC.
Question 23
•
•
•
•
•
User pays principle – allowing value of coastal region to be represented in economic terms – industrial,
agricultural, domestic, and recreational users should pay higher taxes to allow repair of any degradation.
The coastal zone and its waters should not be seen as a commons, but as a limited resource. Waste
treatment should be more rewarding than dumping on land and sea, i.e. high taxes/fines for individuals
and councils which use the land and the oceans as a dump.
Polluting industries on coastal areas should not receive government subsidies or pollution permits, but be
forced by legislation to fully treat their waste.
Precautionary principle applied to resources of the sea where stocks are uncertain.
Deposit systems on plastic bags and bottles to encourage recycling will see fewer of these items in the
sea where they are lethal for marine mammals.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
15
Environmental Science
•
Subsidies for environmentally sensitive house designs which have a low impact on the environment.
(four points for full marks)
Many candidates rewrote green economic notes without explaining how they would impact on the coast or the
marine environment.
Criterion 8
Question 24
The top marks were achieved by candidates who recognized that the problems caused by fossil fuels now e.g.
enhanced greenhouse effect, acid rain and photochemical smog, are too great to wait for the demise of fossil
fuels and that renewable energy technologies should be the immediate goal of governments around the world.
There is no proof that science and technology will fix all problems of species extinction, changed climate and
toxic chemicals.
The few candidates who chose to do this question explained well why they agreed or disagreed with the
optimists points and the examiner awarded most marks for this. Very few answers were specific about strengths
and weaknesses.
Question 25
(a)
The government considers any EIS and public (including environmentalist) comment, but ultimately
discusses legislation and passes or rejects it.
(b)
•
•
•
•
•
Advantages –
Employment in these areas
Income from downstream processing
Renewable energy receives carbon credits
Chip mill on site, logs not carted long distances on state roads
Downstream processing is a requirement of the environmental lobby group.
(c)
Disadvantages –
•
Green opposition vote can lessen the government’s numbers in parliament.
•
Pollutants from the mills and into steams is not good for the state’s clean green image.
•
Clearfelling of old growth forest is not encouraging to tourists.
(six points required for full marks)
In part (a) many candidates simply said that ’the government has the final say’. In (b) many candidates confined
answers to the voting patterns of those pleased or displeased with the approval.
Question 26
(a)
A commons refers to any resource(air, land or water)that is used by all but technically owned by nobody.
By implication, the lack of ownership is linked to a lack of responsibility and guardianship of the
resource.
(b)
Other countries are affected by one country’s misuse of the resource. In this case, the term ‘commons’ can
be applied as the water is not fixed geographically as it travels through several countries; therefore its
presence is transient. (2x2 marks)
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
16
Environmental Science
(c)
Any 4 of:
•
•
•
•
•
•
Provide financial assistance to countries responsible now, for where the pollution emanated
originally
Provide technical assistance to countries responsible now, for where the pollution emanated
originally
Pool resources of all countries involved to remediate rivers and sediments
Take legal action against states or organisations responsible for the pollution if it is still
continuing
Link trade agreements with states/countries to the cleaning up of waterways
Statements in line with ‘green’ economic policy and pollution reduction
Question was generally well done, the majority of candidates having good knowledge of the concept of ‘tragedy
of the commons’ and most suggestions in section b) were logical and showed good knowledge of global issues.
Question 27
Short Term
Tangible
Direct
Indirect
Intangible
Direct
Indirect
Long Term
Tangible
Direct
Indirect
Intangible
Direct
Indirect
BENEFITS
COSTS
Increased employment
Jobs in related industries
Wages, Materials
Disruptions during const.
Power sharing with Vic.
Political support from
pro developers
Disturbance of env.
Adverse reaction from
environmentalists
Electricity sales
Increased jobs
Maintenance
Loss of tourism
Improved Green Image
Tasmanians more united
Visual pollution (pylons)
Loss of view (pylons)
Comments:
This question was too complicated ,too difficult and too time consuming. It was only attempted by a few
candidates and only two gained full marks. It was marked very leniently with the major consideration being
whether candidates understood the difference between a cost and a benefit and between tangible and intangible.
Question 28
(a)
Bioregion Woolnorth with 22.6% lost.
(b)
No. The table contained insufficient data to determine if the resource was used sustainably. Other
information related to future harvesting and regeneration rates and methods of regeneration would be
needed.
Tasmanian Secondary Assessment Board
2002 External Examination Report
EV846
17
Environmental Science
(c)
A cost/benefit analysis would be a good method. It could include the financial costs and benefits of both
logging and tourism. It could include social and environmental costs and benefits. It could consider
direct and indirect costs and benefits and tangible and intangible costs and benefits. An EIA could also be
useful. It could consider environmental impacts of logging and tourism as well as the social and
economic impacts on Tasmanians.
(Five points required. Other methods also considered)
Comments:
(a)
(b)
(c)
Most candidates correctly read the data.
Many disappointing answers. A large number of candidates answered yes. There was little recognition of
the criterion.
Many candidates failed to read the question and wrote long paragraphs on the value of forests. Again there
was little recognition of the criterion.
Question 29
(a)
Countries with the highest access to clean water have the highest life expectancy.
(b)
Group 1 Most Australians have access to treated water and we have a high life expectancy.
(c)
Too many countries represented. Two distinct groups.
(d)
Test normally done on drinking water:
Membrane Filtration - testing for E.coli
Conductivity - testing for dissolved salts.
pH - testing for hardness
Nitrate and Phosphate tests
Other tests sometimes used.
(Any three tests)
All parts of this question were well answered with many candidates gaining full marks. There was some
confusion on the appropriate test for drinking water as opposed to the tests that might be done on an excursion
to a stream.
All correspondence should be addressed to:
Tasmanian Secondary Assessment Board
PO Box 147, Sandy Bay 7006
Ph: (03) 6233 6364 Fax: (03) 6224 0175
Email: [email protected]
Internet: http://www.tassab.tased.edu.au
Tasmanian Secondary Assessment Board
2002 External Examination Report