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Deserts

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Deserts Climate Very hot throughout the year, the temperature of ten remains above 30 C for long periods. Deserts are also very dry places, usually placed in the ... – PowerPoint PPT presentation

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Title: Deserts


1
Deserts
2
Climate
  • Very hot throughout the year, the temperature of
    ten remains above 30C for long periods.
  • Deserts are also very dry places, usually placed
    in the central regions of a continent.
  • They tend to receive an average of less than
    300mm of rain each year.

3
Soils
  • Desert soils are alkaline, and are very dry with
    little humus.
  • However they are not infertile, as areas that
    have been irrigated have produced good crops.
  • Most plants could not survive in the desert soil
    but some have evolved to cope with the lack of
    water and nutrients.

4
Vegetation
  • Plants have to cope with very little water in the
    hot desert.
  • Species such as cacti have evolved to reduce
    water loss to a minimum.
  • Their waxy skins and spiky leaves reduce
    transpiration, whilst their thick stems act as an
    excellent water store.
  • Other plants have evolved extensive, deep root
    systems that search out the last drops of water
    underground, whilst others have all their roots
    very close to the surface in an attempt to
    capture all available rainwater.
  • Due to lack of water plants are often found
    widely spaced apart.
  • Many plants have seeds that only germinate when
    the rains come.
  • They can lie dormant for years, and then burst
    into life with the rains.

5
Human Uses Of Deserts
  • Oil
  • Humans have found little use in the hot, dry
    desert regions of the world.
  • However one very important resource that is found
    in some desert regions is oil, which is essential
    for most countries of the world.
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