Gcse Geogrpahy Desserts revision

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  • Created by: angel 123
  • Created on: 03-08-16 03:26
What is an extreme Enviroment?
A region / place:people find difficult to live in:Lack of water,Lack of food,Dangerous Animals...
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Population Density
The amount of people livng in one area
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During the day in the dessert
Cloudless rays from sun reach ground. Ground heats up.Tempratures near ground reach near 40*
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At Night in the Dessert
No Cloud - prevent heat escaping into atmosphere.Sun Goes down no heat.
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Trade-Wind Desserts
Winds blow from sub-tropical areas with high presure towards Equator.
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Coastal Desserts
Cold air currents near coasts cools so: does'nt rise.There is no rain
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Rain-Shadow Desert
Wind blows across mountain range: Air loses moisture.Rainshadow created on lee-way.
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Monsoon Desert
South-West Monsoon brings rain that falls mainly on Himalayas.North-East Monsoon brings dry weather
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Where are deserts usually found?
Close to the Equator,to the west of Continents,between 10 and 30 south of the Equator,10 and 30 north of the Equator,Tropic of Cancer,Tropic of Capricorn
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Transportation
How Rocks and sand get around the desert
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Erosion
The wearing away of rocks
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Deflation
Gradual rmoval of sand and dust to leave a flat hollow/surface in rocks.
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Exfoliation
layers of rock peel of due to contrasting tempratures during night and day
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Freeze-Thaw
Moisture in air collects in crack of Rock.Extreme Cold in moisture freezes;cracks is expanded where moisture is stored.
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Abrasion
Sand blasting effect of sand particles in wind.Erodes Rock into unsual way.
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Salt Crystilisation
Moisture draws out heat from rock then evaporates.Rock expands as crystalises:Rock Splits
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Traction
Largest particles cannot be picked up.Instead rolled away along surface of desert.
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Hydration
Chemicals in rock react with water.Begins to break down rock.
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Saltation
Particles between 0.25 and 0.15 diameter bounce/jump along desert surface
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Suspension
Samllest Particles:Less than 0.15 in diameter.Light enough to be carried b wind
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Plateu
High,flat area of land
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Canyon
Deed,steep sided valley
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Mesa
Flat-topped mountain with steep sides
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Butte
Small ,isolated flat-topped mountain
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Alluvial Fan
Fan-shaped river.Deposites at foot of steep mountain
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Yardang
Narrow,steep-sided ridge
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Wadi
Small isolated flat-topped mountain
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Inselberg
Large,isolated outcrop of hard rock
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Salt pan
Dried-cut salt lake with a crusty salt surface.
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Blow-out
Large hollow scooped from surface by wind
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Sand dune
Ridge/Mount of sand
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Desert Pavement
Flat-Topped mountain with steep sides.
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Oasis
Ferile area:Where hollow reaches underlying water
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Xerophytes
Whole body of cactus is green.Takes on role of photosynthesis.Body of Cactus is pleated.When it rains:Swells up to take water in.Spikes pines/needles:Ensures Cactus is surrounded with full air.
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Desert plants have two types of Roots:
Shallow ones: Surfaces rain water.Deep ones:Reaches underground water that is stored.
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Ephemerals
Plants change behaviour to suit desert climate.Exists by avioding droughts.
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What makes feature do Camles have that make them adaptable to the dessert?
Tough leather knee pads:To kneel on hot sands.Thick woollly fur:Insulates.Keeps warm at night.Long powerful legs:Travels upsand dunes/across sand.
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Bedoun people:Normads
Clothing:Women wear burkas to protect heads and faces.Men wear head cloths:Keeps out heat,Cold,Wind and Sand.Loose fitting;Allows air to circulate around body:Prevents sweat fom evaporating quickly.
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Bedouin people Transportation
Camels walk long distanceswithout stopping for food /water.Best method Camel:Carries heavy loads.
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Bedouin people:Farming
Use land and Vegetation to keep cattle alive;keep warm.Overgrazing and firewood:Desrtification.
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Bedouin People:Water
Oasis:Caused by natural rising source.most reliable source.Lines of pigeones/Pllants/Mosquitoes means water is nearby.
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Bedouin Peope:Shelter
Tent provides:Warmth and Protection from rain and cold night rain.Tent made of goat skin:Insulates.
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Desertification
Process land becomes desert.Land is damaged.Cant return to original state.
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OverGrazing
Cattle left to graze on land.Remove vegetation as they graze on land.Soil is left vunerable to Erosion: By wind
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Over-Culivation
Year on year:Farmers plant crops use up nutrients in soil.If nutrients not replaced,nothing is grown:Vegetation cover is reduced.Soil erosion by wind is increased.
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Examples where desserts are sustained
Las Vegas and the Mojave Desert:Diverts water supply form Lake Mead-Colorado River.Usage of recycled water. Removal of water thirsty lawnes
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Chihuahuan Desert.
Overgrazing: By cattle, sheep, and goats. Unsustainable harvesting; illegal poaching present:Threats to the region's biodiversity.
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Other cards in this set

Card 2

Front

The amount of people livng in one area

Back

Population Density

Card 3

Front

Cloudless rays from sun reach ground. Ground heats up.Tempratures near ground reach near 40*

Back

Preview of the back of card 3

Card 4

Front

No Cloud - prevent heat escaping into atmosphere.Sun Goes down no heat.

Back

Preview of the back of card 4

Card 5

Front

Winds blow from sub-tropical areas with high presure towards Equator.

Back

Preview of the back of card 5
View more cards

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