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Chapter 20 review


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

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

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  • 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.
    Unpredictable rain  flash floods
    Plant adaptations
  • 8. Adaptations to Desert Life
    The Wandering Tuareg
    “Blue Men of the Desert”
    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
    The Traditional 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:
    Burkina Faso
  • 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
    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?