Transcript Africa South of the Sahara

Chapter Introduction
Section 1: Physical
Features
Section 2: Climate Regions
Summary
SIME s.a.s/eStock Photo
Regions The physical
environment of Africa south
of the Sahara is diverse. It
ranges from deserts to rain
forests, from mountains to
rolling grasslands to jagged
cliffs. Some areas of Africa’s
interior are very difficult to
reach. How do physical
features influence a
region’s climate?
Section 1:
Physical Features
Physical processes shape
Earth’s surface. Over
thousands of years, the
movement of the Earth’s
tectonic plates has shaped
the landforms of Africa south
of the Sahara. The region’s
landscape includes large
plateaus, rocky cliffs, and
great, steep valleys.
Section 2:
Climate Regions
Geographers organize the
Earth into regions that share
common characteristics.
Africa south of the Sahara has
four main climate regions, each
of which covers a large area.
Similar climate zones appear
north and south of the Equator
in the region. Climates range
from damp rain forests to vast
grasslands to hot deserts.
Physical processes shape Earth’s
surface.
Content Vocabulary
• escarpment
• gorge
• rift valley
• industrial
diamond
Academic Vocabulary
• series
• principal
Do you believe reliable water and
sanitation systems should be
provided by the government or
private companies?
A. Government
B. Private companies
C. Neither
D. Not sure
0%
A
A.
B.
C.
0%
D.
B
A
B
C
0%
D
C
0%
D
Without warning, in the mid-1980s, huge amounts of
poisonous carbon dioxide gas escaped from Lakes
Nyos and Mounoun in Cameroon, killing more than
2,000 people. The gas originated in volcanic magma
underground and eventually seeped into the lakes,
where it exploded. Special pipes now control the
release of the gas in harmless amounts.
Landforms of Africa South
of the Sahara
Africa south of the Sahara
consists mainly of vast
plateaus with few mountains
and lowlands.
Landforms of Africa South
of the Sahara (cont.)
• Almost all of Africa south of the Sahara lies
on a series of plateaus.
– The plateaus are formed from the solid
rock that lies under most of the African
continent and rise like steps across the
continent from west to east and from the
coasts into the interior.
Landforms of Africa South
of the Sahara (cont.)
– Many rise from 1,000 to 2,000 feet (305
to 610 m) in western Africa to 7,000 feet
(2,134 m) or more in the east, giving the
area the highest overall elevation of any
world region—more than 1,000 feet
(305 m) above sea level.
Landforms of Africa South
of the Sahara (cont.)
• In eastern and southern Africa, the edges
of plateaus are often marked by steep,
jagged cliffs called escarpments.
– Rivers that flow across plateaus drop
suddenly at escarpments to become
rushing rapids or tumbling waterfalls.
– Escarpments create barriers to trade by
blocking ships from sailing between the
interior and the sea.
Landforms of Africa South
of the Sahara (cont.)
• Lowland areas include a narrow band of
plains that border the region’s Atlantic and
Indian Ocean coastlines and low, sunken
areas called basins.
– Basins formed when tectonic activity
lifted up the land surrounding them.
– The Congo Basin is the largest lowland
area in Africa’s interior.
Landforms of Africa South
of the Sahara (cont.)
• In the east are the Ethiopian Highlands as
well as volcanic mountain peaks, such as
Kilimanjaro and Mount Kenya.
– Kilimanjaro in Tanzania is the highest
peak in the region, rising to a height of
19,341 feet (5,895 m).
– Even though the mountain sits almost on
the Equator, snow covers the summit
year-round.
Landforms of Africa South
of the Sahara (cont.)
• The Great Rift Valley cuts about 4,000
miles (6,437 km) through the flat plateau of
eastern Africa, stretching from Southwest
Asia to Southern Africa.
– A rift valley is a large break in the
Earth’s surface formed by shifting
tectonic plates, volcanic eruptions, and
earthquakes.
Landforms of Africa South
of the Sahara (cont.)
– In some places, the walls rise 9,000 feet
(2,743 m) from the valley floor.
– Features include jagged mountains,
deep lakes, and rich volcanic soil that
supports farming.
Africa South of the Sahara
What do people call the eastern side
of the Drakensburg Range?
A. Shining Mountain
B. Barrier of Pointed Spears
B
A
A. A
B. B
0%
0%
C. C
0%
C
C. Great Rift Valley
Waterways of the Region
Waterways provide
transportation, freshwater,
and electricity for Africans
living south of the Sahara.
Waterways of the Region (cont.)
• Most of the large lakes in Africa south of
the Sahara lie in or near East Africa’s
Great Rift Valley.
• Lake Tanganyika is 420 miles (676 km) in
length, making it the longest freshwater
lake in the world.
Waterways of the Region (cont.)
• Lake Victoria lies in a low basin and is
Africa’s largest lake and the world’s
second-largest freshwater lake, after Lake
Superior in North America.
• Lakes in the Great Rift Valley provide
freshwater and fish to people who live
near them.
Waterways of the Region (cont.)
• Some Great Rift Valley lakes also serve as
the sources of rivers.
• Lake Victoria is the source of the White
Nile, and Lake Tana is the source of the
Blue Nile.
• These two rivers meet farther north in
Sudan to form the Nile River, the world’s
longest river.
Waterways of the Region (cont.)
• Lake Chad, which lies in West Africa,
changes dramatically in size from about
10,000 square miles (25,900 sq. km) in the
rainy season to about 3,800 square miles
(9,842 sq. km) in the dry season.
Waterways of the Region (cont.)
• The same tectonic activity that produced
the region’s rugged landscape also
affected the region’s rivers.
• Escarpments create waterfalls and rapids
that make transportation on some rivers
difficult.
Waterways of the Region (cont.)
• The Zambezi River in southern Africa
plunges over a cliff, creating Victoria Falls,
a series of waterfalls that drop as much as
420 feet (128 m).
Waterways of the Region (cont.)
• Rivers that begin in African highland areas
shape the land.
• Many, like the Congo, flow through
plateaus and carve deep gorges, steepsided valleys formed when rivers cut
through the land.
• Other rivers are interrupted by inland lakes
and marshes that can hinder travel.
What do the region’s four main rivers
have in common?
A. They all originate in Zambia.
B. They all flow into the
Atlantic Ocean.
C. They all begin in the
interior plateaus and
make their way to
the sea.
A. A
B. B
C. C
Mineral Resources
Africa south of the Sahara
holds both a great variety and
large quantities of mineral
resources.
Mineral Resources (cont.)
• Plentiful petroleum deposits are found
along the Atlantic coast from Nigeria to
Angola and in landlocked Chad and
Sudan.
• Oil has replaced agricultural products as
the principal export in many countries.
Mineral Resources (cont.)
• Natural gas is found in Central African
countries along the Atlantic coast; Nigeria,
the Democratic Republic of the Congo,
and the Republic of South Africa have coal
deposits.
Mineral Resources (cont.)
• Large reserves of iron ore exist throughout
Africa south of the Sahara, including vast
amounts in Zimbabwe.
• Chromium, needed to make steel, is mined
in Zimbabwe, South Africa, and several
countries of both West and East Africa.
• Deposits of uranium—used to produce
nuclear power—and copper are also found
in the region.
Mineral Resources (cont.)
• South Africa is believed to have half of the
world’s gold and is also rich in platinum.
• Many gemstones are mined in the region,
including diamonds, rubies, emeralds, and
sapphires.
• Industrial diamonds mined here are used
to make drills, saws, and grinding tools.
What important resource does the
fast-flowing rivers provide?
A. Hydroelectric power
B. Nuclear power
C. Petroleum deposits
D. Gold
A.
B.
C.
D.
A
B
C
D
Geographers organize the Earth into
regions that share common
characteristics.
Content Vocabulary
• drought
• ecotourism
• rain forest
• savanna
• canopy
• desertification
• deforestation
• succulent
Academic Vocabulary
• annual
• enormous
What kind of climate would you prefer
to live in?
A. Mediterranean
B. Tropical
C. Highland
D. Desert
0%
A
A.
B.
C.
0%
D.
B
A
B
C
0%
D
C
0%
D
Uganda, second in the world in banana production, is
looking into making paper with banana fibers instead of
with traditional wood pulp from trees. The process uses
the stems and leaves from the banana plants that are
otherwise thrown away as waste. If it works, banana
farmers will be able to sell both the fruit and the waste,
boosting the economy, and the environment will have
another protection against deforestation.
Factors Affecting Climate
Most of Africa south of the
Sahara has warm or hot
climates. Rainfall, however,
varies greatly throughout the
region.
Factors Affecting Climate (cont.)
• Africa south of the Sahara lies mainly in
the Tropics, resulting in direct rays of the
sun year-round and generally high
temperatures.
• Places with high elevation, though, often
are cooler than lowland areas at the same
latitude.
• Africa south of the Sahara has wet, dry,
and temperate climate zones.
Factors Affecting Climate (cont.)
• Some parts of Africa south of the Sahara
have long droughts, or periods of time
when there is no rain at all.
• Droughts can cause crop failures and
widespread starvation.
Africa: Climate Zones
How much rain falls in the Namib
Desert in Southern Africa?
A. More than 80 inches
(203 cm) per year
B. None
C. Less than 10 inches
(25 cm) per year
0%
A
A. A
B. B
C.0%C
B
0%
C
Tropical and Dry Climates
Most of Africa south of the
Sahara is covered by tropical
or dry climate zones.
Tropical and Dry Climates (cont.)
• A tropical wet climate is found along the
Equator in Central Africa and West Africa.
• Hot temperatures and plentiful rainfall in
this zone support the growth of rain
forests, or dense stands of trees and
other plants that receive high amounts of
precipitation each year.
Tropical and Dry Climates (cont.)
• In a rain forest, vegetation grows at
several different levels.
– The forest floor has mosses, ferns,
and shrubs.
– Above these, palms and other trees
grow about 60 feet (18 m) high.
– The tops of the highest trees form an
umbrella-like covering called the
canopy, which is alive with flowers,
fruits, monkeys, parrots, and snakes.
Tropical and Dry Climates (cont.)
• Rain forests support an enormous variety
of plant and animal life.
• But because many tropical African
countries rely on the sale of products from
the rain forests, such as wood, for income,
they take part in the widespread clearing
of forestland, called deforestation.
Tropical and Dry Climates (cont.)
• The soil on the cleared lands quickly
becomes less fertile, causing farmers to
clear even more forestland.
Tropical and Dry Climates (cont.)
• To preserve rain forests, and boost their
economies, some African countries are
encouraging ecotourism. Ecotourism is
touring a place without causing harm to
the environment.
Tropical and Dry Climates (cont.)
• Farther from the Equator, rain forests give
way to great stretches of grasslands with
scattered woods, called tropical
savannas, where temperatures remain hot
all year, but rainfall amounts are much
lower than in rain forest areas.
– Savanna grasslands are home to
elephants, lions, rhinoceroses, and
giraffes.
Tropical and Dry Climates (cont.)
• Continuing farther from the Equator,
rainfall becomes more scarce, and
savannas merge into drier steppes
that have only about 8 to 15 inches
(20 to 38 cm) of rain over the course of
a few months each year.
– Vegetation includes different varieties of
trees, thick shrubs, and grasses.
Tropical and Dry Climates (cont.)
• Steppe areas are threatened by
desertification.
– Climate changes that bring long periods of
extreme dryness and water shortages
lead to desertification.
– Clearing areas of trees and other
vegetation for herding large amounts of
livestock can also damage and dry out
the land.
Tropical and Dry Climates (cont.)
• The Sahara Desert in the north has high
temperatures and little rain.
– Instead of sandy dunes, it contains barren
rock or stony plains covered by rocky
gravel.
– Very little vegetation can live outside the
oases and the highlands.
Tropical and Dry Climates (cont.)
• The Kalahari Desert in Southern Africa is
covered by vast stretches of sand.
– It has high temperatures and little rainfall.
When rains do fall, they are immediately
absorbed by the sand, leaving the
surface dry.
– Certain areas of the Kalahari have trees
with long roots that reach the moisture in
the deep sand.
Tropical and Dry Climates (cont.)
• The Namib Desert, along the southwestern
coast, is made up of rocks and dunes.
– This desert is arid, but temperatures tend
to be cooler because of breezes from the
ocean.
– Fog that forms along the coast reaches
the desert and provides moisture to many
varieties of succulents, or plants, such as
cacti, with thick, fleshy leaves that can
conserve moisture.
What factors are threatening the
savanna plants and animals of Africa
south of the Sahara?
A. Hunting
B. Human settlement
C. Pollution
D. Both A and B
A.
B.
C.
D.
A
B
C
D
Moderate Climate Regions
Small areas of Africa south of
the Sahara have moderate
climate regions.
Moderate Climate Regions (cont.)
• Moderate climates, with comfortable
temperatures and enough rainfall for
farming, are found in coastal Southern
Africa and the highlands of East Africa.
• Southeastern Africa has a humid
subtropical climate of hot, wet summers
and mild, wet winters.
• The farther south you go in this region, the
farther you are from the Equator, resulting
in cooler temperatures.
Moderate Climate Regions (cont.)
• Southwestern Africa has a Mediterranean
climate in which winters are mild and wet,
but the summers are warm and dry.
– Most rainfall occurs during the area’s
winter months.
Moderate Climate Regions (cont.)
• Highland climates are found in areas of
higher elevation in East Africa.
– Temperatures in the highlands are
cooler than in surrounding areas
because of the higher altitude.
– Snow often falls at high elevations, and
vegetation is abundant at lower
elevations.
In Southwestern Africa, in which season are
Christmas, Hanukkah, and Kwanza?
A. Near the beginning
of summer
B. Near the beginning
of winter
C. Near the beginning
of spring
D. Near the beginning of fall
0%
A
A.
B.
C.
0%
D.
B
A
B
C
0%
D
C
0%
D
Landforms
• Most of Africa south of the Sahara lies on a
series of plateaus.
• Africa’s landforms include plateaus and
volcanic peaks.
• Narrow plains hug Africa’s coastlines. In
some places, the plains spread deep into
inland areas.
Waterways
• Most lakes lie in the Great Rift Valley.
Lakes are a source of freshwater and fish.
• The major rivers of Africa south of the
Sahara are the Nile, the Congo, the Niger,
and the Zambezi.
A Tropical Region
• Tropical rain forests have hot
temperatures and plentiful rains
throughout the year.
• The amount of rainfall varies in the
savannas. A variety of animals lives on
these grasslands.
• Several countries have created national
parks to protect forests and grasslands.
Deserts and Steppes
• Deserts dominate the landscape in large
areas of Africa south of the Sahara.
• The main deserts include the Sahara, the
Kalahari, and the Namib.
• Partly dry grasslands near deserts are
threatened by desertification.
Moderate Climates
• Parts of southeastern and southwestern
Africa lie outside the Tropics. They have
moderate climates.
• Highland climates are found in
mountainous areas of East Africa.
• Temperatures in the highlands are cooler
than in surrounding areas because of
higher altitude.
escarpment
steep cliff at the edge of a plateau
with a lowland area below
rift valley
area of low relief flanked by highland
regions that is formed by the moving
apart of two of the Earth’s tectonic
plates
gorge
like a canyon, a steep-sided valley
formed when a river cuts through land
that is being lifted upward
industrial diamond
diamond used to make drills, saws, or
grinding tools to process other
materials rather than as a gemstone
series
arranged in an order and alike in
some way
principal
main or primary
drought
long period of time without rainfall
rain forest
dense stand of trees and other growth
that receives high amounts of
precipitation each year
canopy
umbrella-like covering formed by the
tops of trees in a rain forest
deforestation
cutting down of forests without
replanting new trees
ecotourism
type of tourism in which people visit a
country to enjoy its natural wonders
savanna
broad grassland in the tropics with
few trees
desertification
process by which dry areas turn into
desert
succulent
type of plant that has thick, fleshy
leaves that can conserve moisture
annual
occurring once a year
enormous
very big
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