GRADE 10 LIFE SCIENCES
June 2008
MEMORANDUM
SECTION A updated by OP 15/6/2008
QUESTION 1
1.1.1 A
1.1.3 D
(2)
1.2.1
1.2.2
1.2.3
1.2.4
decomposer
alcohol/ethanol
spongy mesophyll
taxonomy
(4x1=4)
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.4.1
D
I
C
G
M
E
B
(7x1=7)
-atmospheric fixation by lightning√ and through nitrogen fixing bacteria
which turn ammonia to nitrite and nitrate√
(2)
-via denitrifying bacteria
(1)
-decomposers convert dead organisms into ammonia
-nitrogen fixing bacteria convert atmospheric nitrogen into ammonia
-in excretion nitrogen in urea is converted into ammonia
(3)
1.4.2
1.4.3
must describe and refer to ammonia as end product
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5
1.6.1
1.6.2
1.6.3
Temperature√ – independent variable√
(2)
used same amount of flour/used same number of beetles/ran experiment for
both sets over the same time/same size jar (any 2)
(2)
20 √°C√
(2)
A
(1)
the higher√ the temperature the greater√ the chance that
beetles of species A will outlive beetles of species B (read the
sense of the answer as some conclusions may differ but must mention
species A and species B)
(2)
in the leaves√ of plants directly below the upper epidermis√
(2)
1-cell wall
5-nucleus
6-cytoplasm
(3)
4- plays a role in photosynthesis (must mention photosynthesis)
6- medium in which chemical reactions take place (accept other correct
answers)
(2)
1
Section B
Question 2
2.1.1
Table showing carbon dioxide emissions from various
industries in South Africa√
Industry responsible for carbon
% carbon dioxide
dioxide emissions
released
Coal industry√
82√
Oil consumption√
16√
Cement manufacture consumption√
2√
1 mark for table done with column headings
(8)
2.1.2
2.1.3
2.3.1
2.3.2
2.3.3
-development of industry√ released huge amounts of gases√ including
carbon dioxide into the atmosphere
-increase in human population√ causes an in crease in CO2 release
from all the litter they dispose√ of in dump sites
-deforestation√ means that there are less plants to remove the CO2 from
the atmosphere as a result of photosynthesis√
-increase in buildings….. and cars….
(any 3)
-lead to global warming that leads to a loss of biodiversity/ Increased
CO2 levels cause an increase in global temp as these gases trap infra-red
radiation that leads to global warming
( each boy might have a slightly different interpretation of this question
so read the sense of the answer)
(2)
/13/
A-succulent or Nama Karroo
(1)
-It’s average temperature in summer ranges from 26ºC to 28ºC.
-It’s average temperature in winter ranges from 6ºC to 8ºC.
-It rains all year round.
-It’s rainfall average ranges from 800ml to 600ml
-Tall trees like yellowwood and stinkwood
-Large, soft and shiny leaves
(2)
thick cuticles on leaves/ stomata on lower leaf surface/ leaves covered in
silver hairs/ stomata sunken/ leaves angled at right angles to sun/ leaves
shade each other/ thorns on leaves to discourage herbivores/ leaves are
fleshy (any 3)
(4)
[30]
Question 3
3.1.1 - there was a lack of development in the racecourse
- lack of alien vegetation on racecourse
(2)
-conserved
3.1.2 Mesembryanthemaceae or Aizoaceae
(1)
3.1.3 In scientific notation the genus and species names are always written
in italics.or it is a species and species are written in italics (1)
3.1.4 -medicinal benefits√ that may cure diseases like cancer or HIVAIDS√/
-creates an aesthetically pleasing√ Earth that humans can gain
much pleasure√ from
2
-need to conserve it as a varied food source√ that benefits people
that are malnourished√
-drought and flood control by preventing soil erosion
-recycle nutrients to enrich soil
-provide habitat for many species (any four) May supply
different answers to the above but read the sense of the
answer given.
(4)
SECTION C
Question 4
4.1
A note on the water cycle
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The water cycle, also known as the hydrologic cycle, describes the
continuous movement of water√ on, above, and below the surface
of the Earth.
The sun heats the plants and water√ across the earth’s surface.
Water transpires√ from plants and grass across the earths surface,
condenses√ and forms water vapour.
Water evaporates from lakes, the sea, rivers and soil which also
condenses to form water vapour√.
Ice and snow can sublimate√ directly into water vapor.
The water vapour rises into the air where cooler temperatures cause
it to condense√ into clouds.
Air currents move clouds around the globe, cloud particles collide,
grow, and fall out of the sky as precipitation√.
Precipitation can fall in the form of rain, sleet, hail, snow and fog√.
Most precipitation falls back into the oceans or onto land, where, due
to gravity, the precipitation flows over the ground as surface
runoff.√ A portion of runoff enters rivers in valleys in the landscape,
with stream flow moving water towards the oceans.
Some precipitation falls as snow and can accumulate as ice caps√
and glaciers, which can store√ frozen water for thousands of years.
Snowpacks in warmer climates often thaw and melt when spring
arrives, and the melted√ water flows overland as snowmelt.
Runoff, and ground-water seepage, accumulate and are stored as
freshwater in lakes.
Not all runoff flows into rivers. Much of it soaks into the ground as
infiltration√.
Some water infiltrates deep into the ground and replenishes aquifers
(saturated subsurface rock), which store huge amounts of
freshwater for long periods of time.√
Some infiltration stays close to the land surface and can seep back
into surface-water bodies (and the ocean) as ground-water
discharge.√
Some ground water finds openings in the land surface and emerges
as freshwater springs√. Over time, the water continues flowing,
3
some to reenter the ocean√, where the water cycle renews itself.
(2+10)
4.3
Sample Answer
Opinion :Yes I agree that the maintenance of the rich biodiversity of the
earth underpins the health of the planet and has a direct impact on all our
lives.√
How biodiversity has underpinned the health of the planet:
Biodiversity underpins the
health of the planet because it leads to:
-Greater vulnerability to natural disasters√
-Suffering the greater effects of global warming√.
The loss of biodiversity also
has an impact on our daily lives because with it comes the fact that millions of
people face a future where:
-food supplies are vulnerable to pests and disease√
-water is in irregular or short supply√.
-Fewer new medicines√ will be developed
-Leads to overall new health problems√.
How the loss of biodiversity has had an effect on our lives:
Reasons for loss of biodiversity :The
main reasons for this loss of biodiversity could
be found in over fishing√ and hunting√, along with farming√pollution√ and
urban expansion√.
CRITERIA
MARKS
Viewpoint of
topic given
Viewpoint not
stated
0
Viewpoint
clearly stated
Three reasons
to show how
biodiversity
has
underpinned
the health of
the planet
No supporting
point stated
1
One supporting
point stated
0
1
Two
supporting
points stated
Three supporting
points stated
3
2
4
Three effects
that the loss of
biodiversity has
had on our lives
No effects
mentioned
Three reasons
for the loss of
biodiversity
No reason
mentioned
0
0
Synthesis
Not attempted.
Nothing written
other than the
question
number.
0
One effect
mentioned
Two effect
mentioned
1
2
One reason
mentioned
Two reasons
mentioned
1
2
Three effects
mentioned
3
Three reasons
mentioned
3
Attempted but
with significant
gaps in the
logic and flow
of the answer.
Minor gaps in
the logic and
flow of the
answer
Well structured.
Demonstrates insight
and understanding of
the question.
1
2
3
TOTAL: 150
5
6