A recap of the material covered in Chapter 20 of Geography Alive textbook.

1. CHAPTER 20 REVIEW: LIFE IN
THE SAHARA AND THE SAHEL:
ADAPTING TO A DESERT REGION

2. Introduction
 Oasis: An isolated spot where water is found
in the desert.
 Drought: Long periods with very little or no
rain.
 Physical Features: Mountains, lakes, rivers,
etc.
 Climate:The average temperature of a given
place.

3. The Geographic Setting
 Sahara covers about 3.5 million square miles
 Bordered by the Red Sea on the east and the
Atlantic Ocean on the west
 Atlas Mountains in the north
 Merges with the semiarid Sahel
 Sahara and Sahel cover all or parts of 15
countries

4. The World’s Largest Desert
 Used to have a wetter
climate, but 6,000 years
ago the climate changed.
 Trade winds:Winds that
begin in the northern
latitudes and blow south
towards the Equator.

5. The Sahel: On the Sahara’s
Edge
 Marginal land: Land that is not well suited for
farming.
 Pastoral nomads: Groups of herders who
move with their animals from place to place
in search of pasture and water.
 Desertification:The process during which an
area of land becomes increasingly dry.

6. The Desert Environment
 Ergs: Great seas of sand with tall sand dunes.
 Regs: Gravel-covered plains.
 Hammadas: High, rock-covered flatlands.
 Wadis: Dry riverbeds that can turn into
raging rivers after a rain.

7. The Harsh Desert Climate
 Temperatures can vary greatly: Night time
below freezing and daytime over 100⁰F.
 Sandstorms
 Unpredictable rain  flash floods
 Plant adaptations

8. Adaptations to Desert Life
 TheWanderingTuareg
 “Blue Men of the
Desert”
 Nomads
 Trade for food
 Camel Caravans

9. Technology Makes Life Easier
 Satellite phones
 Creation of oases
 Better transportation
 Trucks vs. camels
 Planes between oases

10. The Oasis Environment
 Islands of Water
Surrounded by Desert
 Natural creations
 Some man-made
 Large and Small
Centers of Life
 Various plants and
animals

11. Adaptations to Life in the
Oases
 TheTraditional Ways of Oasis Settlers
 Cash crops: Dates, wheat, barley, vegetables.
 Trade for goods
 Homes made of mud bricks
 Work done in the evening
 Windbreaks:A wall or hedge that breaks the force
of the wind.

12. Water Problems Limit the
Growth of Oasis Towns
 Mostly small villages
 Why people move here
 Jobs at factories
 Pasture for animals
 Refuge from drought or wars
 Kinds of water problems
 How to get water during expansion
 Water shortages

13. The Sahel Environment
 Includes portions of:
 Niger
 Gambia
 Senegal
 Mauritania
 Mali
 Burkina Faso
 Nigeria
 Chad
 Sudan

14. A Landscape Threatened by
Drought and Desertification
 Natural vegetation: grasslands, acacia trees,
baobab trees, small bushes.
 Not fertile soil
 Water is scarce most of the year
 Farther south=rain more plentiful
 Varied vegetation

15. Adaptation to Life in the
Sahel
 Most people are farmers or herders
 Plant crops : grains like millet and sorghum
 Shifting agriculture: Plant some crops on a
plot of land for a year or two, then planted a
different field.
 Herders use a similar system to feed the animals

16. Human Causes of
Desertification
 Cash crops
 Overgrazing of cattle
 Deforestation: Cutting
down trees for various
uses.
 Erosion:The process of
wearing down a piece
of land.

17. Beginning to Think Globally
 1/3 of Earth’s land is
arid or semiarid
 Some desert regions
expanding
 China
 Sandstorms
 Desertification
A sandstorm in China.

18. Global Connections
 Are the world’s deserts
growing or shrinking?
 What human activities
contribute to
desertification?
 How might people
adapt to living in areas
threatened by
desertification?