Download central yearly meeting of friends (cymf) -2016

CENTRAL YEARLY MEETING OF FRIENDS (CYMF) -2016
GEOGRAPHY 312/1
PAPER 1
MARKING SCHEME
SECTION A
1. a)Give two reasons why the interior of the earth is hot



The earth still retains the original heat which it had before it started cooling
The interior of the earth is made up of radioactive materials that constantly
explode generating heat
Immense weight of crustal rocks puts pressure on rocks beneath hence
generating heat
(First 2x1=2mks)
b) State three effects of revolution of the earth
(3mks)



Development of the four seasons
Variation of the length of day and night at different times of the year
Change s in the position of the midday sun at different times of the year at
different latitudes
 It leads to development of solar and lunar eclipse
2. . (a)What is a mineral?
(2mks)
A mineral is an inorganic substance which occurs naturally at or beneath the earth’s
surface.
(b)State three characteristics of minerals




Minerals have different degree of hardness
They differ in texture they have specific colour
They have specific luster
They have specific tenacity
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(3mks)
3. “(a)
P-escarpment
Q-Hade
(b)
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
Nyandarua
Kedong
Kikuyu
Nguruman
Mau
Nandi
Nyando
4. (a) Process of chemical weathering
 Solution
 Carbonation
 Hydrolysis
 Hydration
 Oxidation
(b) Ways in which plants causes weathering


Plants wedge their roots through rock cracks widening and breaking them
Plants decay and produce organic acids which react with rock minerals
hence leading to disintergration
 Lichens and mosses create moist environment on rock surfaces hence
reacting with rock minerals
5. (a)Two reasons why wind action is dominant in desert
(2mks)
 Presence of loose/unconsolidated dry masses of particles are easily carried by
wind as it blows
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
Strong tropical winds are common in hot deserts the absence of vegetations
covers to protect the surface from wind .
(b)Three characteristics of barchans
(3mks)
 A barchans has two horns
 It has a genthe windward slope
 It has a steep slope /concave slope on the leeward side
 It has a height of 25 -40 metres
 It lies at right angle to the prevailing wind
 Barchans occurs in groups
6. (a) (i) 217343
(ii) Full square 21
Half square 17
17
/2 =8.5
21+8.5
29.5km2/29.0/30
(iii) 12.4km/12.3/12.5
(2mks)
(b)(i) Describe the drainage of the area covered by the map







(3mks)
(5mks)
The area has many rivers e.g river Sio
Most of the rivers are permanent
River Sio flows from north east towards the west
There are many swamps towards the north
Most rivers display dendritic pattern
Rivers originating from Samia hill exhibit radial drainage pattern
There is a reservoir at grid square 2134
(ii) Three settlement patterns in the area covered by the map



Linear along road C 529
Nucleated /clustered around Funyula market
Dispersed along STO river
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(3mks)
(d)
CROSS SECTION ALONG NORTHING 37 FROM EASTING 28 TO 33
(ii) V.E=
=
V .S
H .S
1
1

10,000 50,000
=10,000 X
=
50,000
1
50,000
10,000
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7. (a) (i)Other two processes of soil formation
 Leaching
 Organic accumulations
 Cheluviation
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(2mks)


Precipitation organic sorting
Organic sorting
(ii)Explain how Eluviations occur


(3mks)
As water percolates through the soil it mixes with fine minerals particles and
washes them down mechanically and in suspension from the upper layer to
lower layers
When water peculates horizontally, the materials are transferred horizontally
as well.
(ii)Explain how illuviation occur


(3mks)
The materials that have eluviated from the upper soil are deposited and
accumulate in the lower soil layers
This may sometimes lead to formation of a hard pan of latorite where the
materials accumulate.
(b)(i)Factors that influence soil formation



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
Parent materials
Living organisms
Climate
Time
Topography
(ii)Effects of soil erosion on water sources






(3mks)
(6mks)
When eroded ,soil is deposited in water reservoir, it leads to siltation hence
reducing the capacity / volume of water in the reservoir.
Eroded soil may contain pollutant agricultural chemical/industrial influence
making water dirty/unsuitable for use.
When eroded soils accumulate in water reservoir ,it makes them shallow
and plants may colonize them turning into a swamp
Accumulation of eroded soils into rivers valleys makes them shallow
resulting to frequent floods
When the soils accumulates in river valleys ,they may block the path of water
causing a lake to form on the upstream.
Siltation caused by deposition of soils into a river bed may make a river
shallow hence unsuitable for navigation.
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(iii)Four uses of soil





(4mks)
Soil are used to make pottery and other materials
Soils are used for growing crops
Soils are used for building houses
Soils are used as animals lick when such soils contain the required mineral
salts
Some soils are used for ornamental purposes e.g Red Ochre
(c )(i)Two characteristics of soil



(2mks)
Soil colour
Soil texture
Soil permeability
(ii) ways of collecting information in the field
(2mks)
 I would observe what people do to the soil
 I would collect soil sample
 I would photograph people engaged in various activity pertaining soil
 I woild ask people in the field questioning about soils and their types
 I would read from books and pamphlets on soils
8. (a) Name two examples of relief features found on the floor of the Rift valley(2mks)
 Depressions occupied by lakes
 Volcanic mountains
 Crates/calderas
 Valleys
(ii) statges involved in the formation of fault mountains
(8mks)
Crustal rock layers are subjected to compression forces
This leads to formation of two adjacent reverse faults in the rock strata
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The middle block experience Upliftment
This leads to formation of a raised land mass between the two reverse faults which
is called a fault mountain
Text -4mks)
Diagrams -4mks)
Total -8mks
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(b) (i)



A-Fault/faultline
B-Fault step
C-Crustal rock layer/strata
(ii) Four characteristics of lakes formed by faulting
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
(4mks)
Most of them are deep
Most of them are saline /salty
Most of them are narrow/elongate
Most of them have steep sides
(c ) Explain four effects of faulting to human activities

(8mks)
Windward sides of fault mountains regere relief rainfall that supports crop
farming.
 Fault mountains are sources of rivers that have
waterfalls for H.E.P
generation/fishing/industrial use
 Fault mountains areas are thickly forested on windward side hence
supporting tourism/lumbering
 Faults steps /Rift valleys /escarpments attracts tourists for foreign exchange
 Faults form lodes /veins in which minerals occurs hence supporting mining
 Leeward sides of fault nuts receives low rainfall that limit profitable crop
farming
 Steep slopes of fault mts/faults scarps make construction of houses difficult
hence discourage human settlement.
9. (a) (i) What is natural vegetation
(2mks)
 Is the plant cover that grows on the earth’s surface on its own without interference
by people?
(ii)How altitude and wind influence the distribution of vegetation
(8mks)
 --Altitude
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
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Low altitude with worm condition moisture have luxuriant vegetation
Mid-latitude especially on the windward slopes support luxuriant vegetation
Above 3000m above the sea level have coniferous forests and bamboo
Above 3000m have health and moorland
 Winds
 Areas with moist winds which experienced high precipitation have plenty of
trees while areas with drought conditions have drought resistant plants
 Winds helps in seed dispersal hence windy areas have a wide variety of
vegetation
(b)In which major climatic regions of the world are the following types of
vegetation found
(i) Selvas
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(1mk)
Equatorial
Equatorial monsoon
Tropical marine
Tropical monsoon
(ii)The marquis or chaparral
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(1mk)
Warm temperature western
Margin (Mediterranean climate )
(iii)The pambas

(1mk)
Warm temperature continental climate
(iv)Taiga

(1mk)
Cold temperatures continental climate
(c ) State five characteristics of the coniferous forests of the cold temperature climate
(5mks)
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Most trees are softwoods
Trees mature fast
Common trees include fir, pine and larch
Most trees are evergreen
Trees have big proportion of stem compared to leaves
Trees occurs in pure stands
Trees have little undergrowth
Trees have needle-like leaves
Trees form canical shape
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Trees trunks are flexible
(ii)Explain three ways in which the trees in these forests are adopted to the
climate conditions
(6mks)


Trees have needle-like leaves to reduce water loss
Trees have conical shape and flexible branches to allow snow to slide off
easily
 Most trees are evergreen so as to have maximum utilization of sunlight
during the short growing season
10. (a) (i)What is a rock ?
(2mks)
 The solid substance made up of aggregate of minerals that forms the earth’s crust
(ii)Examples of plutonic rocks
(2mks)
 Gabbro
 Granite
 Diorite
 Peridotite
 Syenite
(b)(i) State three characteristics of sedimentary rocks
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They occur in layers
Some contains fossils
Some are elastics
(ii) Describe how mechanical formed sedimentary rocks are formed
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(3mks)
(4mks)
Already existing rocks undergo weathering forming sediments/particles
The sediments are transported by running waters
The sediments are deposited in layers in the lowlands
The sediments undergo compaction and cementation and harden into a rock
It is this rock formed from sediments from pre-existing rocks that we call
mechanically formed rocks
(c )Explain four ways in which rocks contributes to the economy of Kenya
(8mks)
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Some rocks contain minerals that are mined to earn income
Some rocks attracts tourists who bring in foreign exchange
Some rocks are used as curving items sold to earn income
Some rocks provide minerals food supplements hence reducing on costs of
buying such supplements.
Some rocks weather e.g basalt to form fertile soils for commercial crop
farming
some rocks surfaces are used for advertisement hence supporting trade
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
Some rocks are excavated and used for building commercial houses.
(d)(i) Give two reasons why you might have conducted a reconnaissance for
the study
(2mks)



To ask for permission /to notify respondents
Estimate the time /duration for the study to enable us draw an appropriate
time schedule /working schedule to identify appropriate route
To enable them choose appropriate methods of data collection
(ii)State four problems you might have encountered during the field study
(4mks)
Muddy roads that slowed movement few resources experts in metamorphic rocks
Heavy rains that led to delays as we shelter
Long distances covered while walking that caused fatique/tiredness
Fear of wild animals attacks from bushes in the neighborhood.
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