1. GURU CHARAN KUMAR 2013
ESS GRADE 11 SUMMATIVE-SEPTMEBER 2012-ANSWER SHEET
1) (a) (i)
1
(ii)
(b)
solar energy/the sun
Evaporation
1
(i)
300
× 100 = 75%
400
need correct answer for the mark, not necessarily working.
(ii)
(c)
1
336
× 100 = 84%
400
1
(i)
100 – 64 or 336 – 300 = 36 × 1015 kg
Award [1] for correct answer (36) and [1] for units (1015 kg).
(ii)
(d)
(e)
Burning fossil fuels releases more carbon dioxide/greenhouse
gases [1]; …
which increases global temperatures [1]; … which melts ice [1];
increased temp. → increased evaporation → increased
cloud cover [1].
Vegetation/plants/animals/organisms/biomass/soil water [1];
Appropriate mechanisms for transfer [2]/
e.g. organisms – water enters by absorption through roots or
digestive system [1];
water leaves by transpiration or excretion (sweating, urination) [1].
(i)
Max 3
1
(accept any two of)
• increase in evaporation/condensation leads to increased
cloud cover [1]; leads to increased reflection of solar
radiation/higher albedo [1];
• increase in precipitation leads to more snow [1]; leads to
increased reflection of radiation [1];
• decrease in the rate of evaporation decreases amount of water
vapour entering the atmosphere [1]; water vapour is a
greenhouse gas (so reducing it will reduce the greenhouse
effect) [1] and/or reducing atmospheric water vapour will
reduce cloud cover [1]; and hence increase radiation loss to
space [1].
(One change in flow [3 max], two changes in flow [4 max])
(iii)
Max 3
Condensation/precipitation/run off/groundwater flow would
increase (because of extra water in atmosphere) [1]
Or: run off/groundwater flow would decrease (because of
extra evaporation from warmer surfaces)
(ii)
2
(Response must follow on from (e) (ii))
4

2. GURU CHARAN KUMAR 2013
For increases in flow given above; feedback is negative [1]
For decreases in flow given above; feedback is positive [1]
1
(If part (ii) is not answered or answer does not mention a
direction of change in flow and its consequences, no credit
can be given here.)
(f)
Transformation = condensation and evaporation [1];
Transfer = precipitation and run off/groundwater flow [1].
2
[20]
2) (a) (i)
feedback that tends to damp down/neutralize/counteract
any deviation from an equilibrium, and promotes stability;
(ii)
(b)
1
feedback that amplifies/increases change (it leads to
exponential deviation away from equilibrium);
most ecosystems contain inbuilt checks and balances;
without internal balance an ecosystem would spiral out of control;
without negative feedback no ecosystem could be self-sustaining;
1
1 max
(c)
smoke
coal
cold water
steam / water vapour / water
energy /
electricity
warm water

3. GURU CHARAN KUMAR 2013
3) a)
(i)
(ii)
(b)
(i)
energy is neither created nor destroyed/energy is
conserved
1
1000 kJ – 100 kJ (10%) = 900 kJ;
output = 900 kJ – 135kJ (15%) = 765kJ;
2
1. evaporation;
2. Transpiration/evapotranspiration;
3. precipitation;
4. run-off/infiltration;
Four correct [2], three or two correct [1].
(ii)
too simplistic/no values/no indication of time/two dimensional;
Accept other reasonable answers.
(iii)
1960 = 2 × 103 km3 yr–1 2000 = 4 × 103 km3 yr–1;
4 2
× 100 = 100%;
2
Correct answer on its own, award [2].
(iv)
increasing global population requiring more water;
industry expanding and requiring more clean water (cooling
processes, etc.);
globally, greater use of water for irrigation;
increase in water use by developing countries;
Accept other reasonable answers.
2
1
2
3

4. GURU CHARAN KUMAR 2013
4)
(a)
(b)
as altitude increases rodent species number decreases;
there are fewer rodent species numbers at high altitude;
there are higher rodent species numbers at low altitude;
inverse relationship;
1 max
Migration of species up the mountain;
melting/loss/reduction of snow cap/migration of snowline up
mountain;
appearance of new species;
loss of species/species unable to adapt to rapid changes/lower
diversity;
increased growth rates;
3 max
c) (ii) an open system exchanges energy and material,
a closed system exchanges energy but not material;
1
(b) Forest as an ecosystem
Sunlight converted by producers;
producers eaten by consumers;
some energy released as heat;
consumers eaten by other consumers;
detritus decay;
3