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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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    Chapter 20 review Chapter 20 review Presentation Transcript

    • Chapter 20 review: life in the sahara and the sahel: adapting to a desert region
    • 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.
    • 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
    • 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.
    • 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.
    • 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.
    • The Harsh Desert Climate
      Temperatures can vary greatly: Night time below freezing and daytime over 100⁰F.
      Unpredictable rain  flash floods
      Plant adaptations
    • Adaptations to Desert Life
      The Wandering Tuareg
      “Blue Men of the Desert”
      Trade for food
      Camel Caravans
    • Technology Makes Life Easier
      Satellite phones
      Creation of oases
      Better transportation
      Trucks vs. camels
      Planes between oases
    • The Oasis Environment
      Islands of Water Surrounded by Desert
      Natural creations
      Some man-made
      Large and Small Centers of Life
      Various plants and animals
    • 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.
    • 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
    • The Sahel Environment
      Includes portions of:
      Burkina Faso
    • 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
    • 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
    • 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.
    • Beginning to Think Globally
      1/3 of Earth’s land is arid or semiarid
      Some desert regions expanding
      A sandstorm in China.
    • 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?