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ESS IB, all the Case studies questions with verified answers A+ graded passed
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ESS IB, all the Case studies questions with verified answers A+ graded passed
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ESS IB, all the Case studiesEvaluate the uses of DTT. - correct answer ✔✔Pros:
- Relatively cheap
- Highly persistent so that it continues for months after application to kill insects such as mosquitoes that
carry disease
- Used to virtually* eliminate malaria dengue fever and filariasis*
- Estimated to have *saved about 50 million human lives* and to have prevented more than *a thousand
million* human illnesses
Cons:
- kills all insects that come in contact with it.
- thinning birds' eggshells; reducing their population numbers
- it is *persistent* -> fall into the food chain => *bioaccumulate and biomagnified*
- affect the development of children e.g in *Yaqui Valley, Mexico*
More detail: https://old.iupac.org/publications/cd/essential_toxicology/IUPACDDTcase.pdf
Evaluate a named historical event that lead to the banning of DTT. - correct answer ✔✔*Rachel Carson:
Silent Spring* - *1962*: Shows the impacts of DTT on the environment and human's health.
Leading to the ban of DTT by world agriculture in *2001*
Pros:
- reduce/stop biomagnification of DDT
- improvement in child's development
- reduce cancer, asthma, pregnancy loss
- environmental system can recover
,Cons:
- Malaria risk increases; more death
- Fewer affective alternative for DDT
- Alternative pesticides are more expensive
Outline the water conservation strategies with reference to a named example. - correct answer
✔✔*Singapore water conservation strategies*
1. Follow the scheme of *conserve, value, enjoy*
2. Increases the *pricing* of water
The Singapore's National Water agency - *PUB* has helped by:
1. *Educate* the population about ways of reducing water demand while doing different activities at
home, school, workplace...
2. Provide *water saving kits* for free: help to control the flowing rate of water
3. Develop a * water efficiency labelling scheme* on the products such as washing machines: more ticks
= more water efficient
Describe and evaluate *the sustainability of freshwater resource usage* with reference to a case study. -
correct answer ✔✔• *Middle East Water shortage*:
o Area contains only *0.5% of the world's freshwater supply and 5%* of the world's population.
o Major drought in *2008 in Israel*. Forced to stop pumping from sea of *Galilee* and draw from
aquifers instead.
Did not restrict water supply to its neighbor *Jordan*.
Israel has *two desalination plants* that supply *one third* of used water for households.
, Potential future conflict over water supplies.
"Discuss, with reference to a case study, the controversial harvesting of a named species." - correct
answer ✔✔*Salmon farming in British Columbia, Canada*
- overfishing in the sea -> not enough salmon to meet the damands
- salmon farms increase; causing pollution
1 . chemicals used in the farm to kill lices are toxic; fishes in the surrounding area have *high level of
tumours lesions and I-parasite*
2 . Food web is affected
3. . When drug *loss efficiency* -> lices may become *stronger*-> affect wild salmon population
4. *Genetically modified* farmed-fishes escape into the wild; interbreed with wildfish -> reduce their
ability to survive
5. high density of fishes in the farm; organic wastes enter the ocean and pollute the water.
*Solutions*
- move the salmon farm to a *close-containment* system technology
- consumers can choose to buy wild salmon instead of the farmed one; putting pressure on the farm to
make changes
Compare and contrast the sustainability of one *wild capture* fishery and one type of *aquaculture*. -
correct answer ✔✔1) Wild capture = *Grand Banks Cod*
- Methods such as *trawler netting*
- *Unsustainable* because: *By-Catch*, destroy ocean floors / endangered ecosystems ( e.g cod ) to
catch the *demersal fishes*
- *High technology* means more fishes can be caught which might *exceed the MSY*, leading to the
depletion to fish population
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