Life in the Sahara and the Sahel: Adapting to a Desert Region

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Life in the Sahara and the Sahel Adapting to a
Desert Region

• Chapter 20

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I. Geoterms

• A. Desertification the process by which land
  becomes more and more dry until it turns into
  desert. This may be caused by climate change,
  human activities, or both.
• B. Drought an unusually long period in which
  little or no rain falls
• C. Marginal Land land that is not well suited
  for growing crops
• D. Pastoral Nomads groups of herders who move
  with their animals from place to place in search
  of pasture and water.

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II. The Geographic Setting

• A. The Worlds Largest Desert
• 1. 3.5 million square miles (size of USA)
• 2. Daytime temperature is 136F.
• 3. About 6,000 years ago climate started to
  change creating a desert
• 4. Trade winds from the north eliminated any
  moisture
• 5. Most plants, animals, people that live here,
  live near oases.

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Worlds Largest Desert
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• B. The Sahel On the Saharas Edge
• 1. Sahel is on the southern edge of the Sahara
• 2. Sahel receives more rain than the Sahara but
  often has long droughts
• 3. Sahel is marginal land which is not good for
  farming (subsistence farming)
• 4. People living here are pastoral nomads (people
  moving from place to place looking for water and
  grazing land for their animals
• 5. Desertification is causing the Sahara to expand

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Sahel
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Nomadic Herdsmen in the Sahel
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III. The Desert Environment

• A. The Desert Landscape More Than Just Sand
• 1. Three landforms
• A. Ergs great seas of sand with tall sand dunes
  over 400 feet high
• B. Regs gravel-covered plains
• C. Hammadas high rock-covered flatlands
• D. Nile and Niger rivers with sources in
  mountains beyond the desert
• E. Wadis dry riverbeds that can turn into raging
  rivers after a rain and then quickly dry up again

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Ergs and Regs
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Hammadas
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Wadi in the Sahara
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• B. The Harsh Desert Climate
• 1. Temperatures daytime 100 degrees, night time
  may drop below freezing
• 2. Sandstorms can reduce visibility to nothing
• 3. Rain is unpredictable with flash floods
  occurring
• 4. Plants adapt to climate
• A. deep roots to anchor it and get moisture
• B. Small waxy leaves that retain moisture

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Sandstorm in Sahara
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Plants of the Sahara
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• Transparency 20B
• Answer questions (20.3) page 150

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IV. Adaptations to Life in the Desert

• A. The Wandering Tuareg
• 1. Nomadic Tuareg raise camels, goats, cattle, or
  sheep
• 2. They move about in search of grazing areas
  (caravans)
• 3. Known as Blue Men of the Desert because they
  wear long blue robes that project them from sun
  and sand

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Nomadic Tuaregs
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• 4. Live in family groups of lt100 people
• 5. Can pack all possessions on just one camel
• 6. They trade (meat, cheese, milk) at oases
• 7. They often travel at night by reading the
  stars and it is cooler

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Tuareg Family
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• B. Technology Makes Life Easier
• 1. Use lightweight plastic and metal containers
• 2. Some use satellite phones to talk to customers
• 3. Drilling machines create new oases by drilling
  through rock to underground water sources
• 4. Trucks and planes being used to transport
  people and goods

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Modern Technology in the Sahara
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• Answer question (20.4) on page 150

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V. The Oasis environment

• A. Islands of Water Surrounded by Desert
• 1. Natural oasis springs bubble up to surface
  from underground or low spots where land dips to
  underground stream
• 2. Human made hand dug wells or machine drilled

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Rain Catchers vs Drilling
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• B. Large and Small Centers of Life
• 1. Sahara has about 90 large oases that can
  support a village and many small ones that can
  only support a family
• 2. Many different plants and animals
• A. Acacia and Baobab trees and shrubs
• B. Gazelles, butterflies, and insects
• C. Date Palms (most important) for fruit,
  building materials, rope, and animal feed

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Oases
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• Transparency 20C
• Answer questions (20.5) on page 151

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VI. Adaptations to Life in the Oases

• A. The Traditional Ways of Oasis Settlers
• 1. Trading and farming is the major economic
  activity of an oasis
• 2. Most people are subsistence farmers
• 3. Some grow cash crops (dates, wheat, barley,
  and vegetables)
• 4. People stop here to trade and get water
• 5. Homes made of mud brick to keep out heat

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Farming an Oases
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People Living on an Oases
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• 6. Most work is done in cooler part of the day
• 7. Windbreaks planted to protect from wind and
  sand
• B. Water Problems Limit the Growth of Oasis Towns
• 1. As oases grow, water must be brought in by
  truck
• 2. If too much water is used for either people or
  crops, it will run out.

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Water at an Oases
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• Answer question 20.6 on page 151.

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VII. The Sahel Environment

• A. A Landscape Threatened by Drought and
  Desertification
• 1. Sahels vegetation is mix of acacia trees,
  baobab trees and small shrubs
• A. North of this is desert lack of rain
• B. South is greater variety of plants due to more
  rain

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Drought in the Sahel
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• 2. Droughts lasting gtsix years
• 3. Desertification
• A. Winds take away soil
• B. Sahara desert is expanding

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• B. Over grazing by cattle is a major cause of
  desertification in the Sahel (causes destruction
  of cover plants, allowing wind or water to erode
  the soil)

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• Transparency 20D
• Answer questions 20.7 on page 151

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VIII. Adaptations to Life in the Sahel

• A. Plant crops that require little water (grains
  like millet and sorghum)
• B. Shifting Agriculture farmers plant on field
  for 1-2 years and then change fields
• C. Human Causes of Desertification
• 1. Farmers plant crops (peanuts) that deplete
  soil faster, then soil blows away
• 2. Herders expanding herds and animals overgraze,
  turning land into desert
• 3. Deforestation people cutting down trees so
  erosion occurs

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Millet
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(No Transcript)
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• D. Agencies trying to correct this problem
• 1. Get people to burn coal rather than trees
• 2. Plant windbreaks
• 3. Conserve water
• 4. Improved farming methods

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Improving Farming Methods
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IX. Globally Desertification Happening Around
Other Deserts of the World

• Transparency 20E
• A. China
• B. Baja California
• C. Peru
• D. Kazakhstan
• E. Australia

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X. Global Connections

• A. Are the worlds deserts growing or shrinking?
• B. What human activities contribute to
  desertification?
• C. How might people adapt to living in areas
  threatened by desertification?