Helena Geography > Deserts > Flashcards

Deserts Flashcards

(51 cards)

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1
Q

What is the average annual precipitation received by deserts?

A

100 to 200 mm

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2
Q

What fraction of Earth’s land area do deserts cover?

A

One-fifth

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3
Q

Approximately how many people live in desert regions?

A

1 billion

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4
Q

What is the classification of Antarctica in relation to deserts?

A

Sometimes classified as a desert due to low precipitation

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5
Q

What are the main characteristics of deserts?

A
  • Lack of clouds
  • Little rain
  • Very hot days
  • Very cold nights
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6
Q

What term describes the extremely dry conditions of deserts?

A

Arid

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7
Q

What phenomenon explains the dryness of desert air?

A

Air descends and is very dry

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8
Q

Why are deserts found along the tropics instead of at the equator?

A

Most moisture has fallen as precipitation over the Equator

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9
Q

What is the diurnal temperature range?

A

The daily temperature range in deserts

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10
Q

In which zones do many hot deserts lie?

A

Subtropical zones

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11
Q

List some of the world’s most famous deserts.

A
  • Sahara
  • Kalahari
  • Atacama
  • Gobi
  • Arabian
  • Great Victoria
  • Great Sandy
  • Mojave
  • Chihuahuan
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12
Q

How are deserts classified?

A

According to the causes of their dryness

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13
Q

What are the five types of deserts?

A
  • Subtropical Deserts
  • Coastal Deserts
  • Rain shadow Deserts
  • Interior Deserts
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14
Q

What causes Subtropical Deserts?

A

Hadley Cell transporting dry air to the Tropics

Examples: Sahara, Kalahari, Northern Australia

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15
Q

What is a Coastal Desert characterized by?

A

Cold ocean currents contributing to fog and little rainfall

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16
Q

What occurs in a Rain shadow Desert?

A

Mountains block moist winds, causing rain on one side and dryness on the other

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17
Q

What defines Interior Deserts?

A

Located in the heart of continents with no moisture-laden winds reaching them

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18
Q

What adaptations do succulents (eg cacti) have for survival in deserts?

A

Ability to store water in their stems

One cactus, 2 cacti!

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19
Q

What are ephemeral plants?

A

Plants with very short life cycles, typically 6-8 weeks

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20
Q

What is the purpose of long and wide roots in desert plants?

A

To absorb maximum rainfall and provide stability in loose soil

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21
Q

What adaptations do many desert animals have?

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A
  • Coping with lack of water
  • Surviving extreme temperatures
  • Dealing with food shortages
22
Q

How do many desert animals avoid daytime heat?

Study These Flashcards
A

By being nocturnal and hiding during the day

23
Q

What sources of water do many desert animals rely on?

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A

Water obtained from their food

24
Q

What changes have occurred in desert lifestyles since the mid-20th century?

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A

Nomadic groups adopting settled ways of life and oasis settlements growing into cities

25
What has contributed significantly to changes in the world's deserts?
Extraction of oil and natural gas
26
What technological advances have helped manage water in deserts?
* Reservoirs * Canals * Pipelines * Desalinization plants * Deep wells
27
What practices have made farming successful in arid lands?
Careful water and land management along with drought-resistant crops
28
Deserts have a * annual temperature range but a * daily range.
Deserts have a LOW annual temperature range but a HIGH daily range.
29
What are some threats to deserts caused by humans?
* Extraction of resources * Hunting * Tourists damaging dunes * Over-grazing * Deforestation * Toyotarisation * Land degradation * Desertification ## Footnote Examples of extraction include copper mining in the Atacama Desert, while over-grazing is prevalent in the Southern Sahara.
30
Define over-grazing
Allowing too much livestock to graze on a piece of land, leading to vegetation loss and increased vulnerability to erosion. ## Footnote Over-grazing makes the ground susceptible to wind and water erosion. Eg in Southern Sahara
31
What is over-cultivation?
Farming land too intensively without fallow periods, depleting soil nutrients. ## Footnote This practice can lead to reduced soil fertility over time.
32
What are the effects of deforestation in deserts?
Reduces nutrients in the land and increases vulnerability to erosion due to the removal of root systems. ## Footnote Trees play a critical role in soil stability and nutrient retention.
33
How does over-population contribute to desertification?
Increases demand for agricultural products, leading to overuse of land and resources.
34
What are the consequences of fertilizer and pesticide use?
Can artificially increase crop yields but may lead to nutrient depletion and pollution of local water sources. ## Footnote Prolonged use can degrade land quality and increase vulnerability to erosion.
35
What does HYV stand for?
High Yield Variety.
36
What is the impact of unsustainable water use?
Can lead to aquifer depletion and increased aridity in affected areas. ## Footnote The Aral Sea is a classic example of unsustainable irrigation practices.
37
How do rising temperatures affect vegetation in deserts?
Make it harder for vegetation to grow, reducing cover and increasing erosion risk.
38
What happens when there is decreased rainfall in desert regions?
It becomes increasingly difficult for vegetation to grow, making the ground more vulnerable to erosion.
39
What are the effects of dust storms?
Soil becomes less stable and more vulnerable to wind erosion, leading to large-scale dust storms. ## Footnote Northern China experiences increased dust storms due to desertification south of the Gobi Desert.
40
What are the implications of reduced crop yields?
Can lead to famine and starvation as the soil becomes less fertile.
41
How can conflict arise from soil degradation?
Diminishing agricultural output and land can lead to competition for scarce resources.
42
What is the relationship between famine and soil degradation?
Famine can be caused by soil degradation, drought, and conflict, making the potential for famine greater.
43
What is crop rotation?
Growing different crops each year to allow soil nutrients to recover during fallow periods.
44
What is the purpose of reforestation and afforestation?
To protect farmland from erosion and return land to its natural state, enhancing fertility and stability.
45
What are grazing quotas?
Limits on the number and types of animals that can graze on land to prevent vegetation destruction.
46
What role does population control play in resource management?
Helps limit agricultural land needs and farming intensity by managing population growth.
47
What are GM crops designed to do?
Withstand poor soil and water shortages while potentially adding nutrients back to the soil.
48
True or False: Toyotarisation refers to the use of 4x4 vehicles that harm the desert environment.
True ## Footnote Langstrand
49
What does overuse of GM and HYV crops lead to?
Overcultivation and a reduction in soil quality
50
Why has the Aral Sea depleted so much?
Due to the diversion of its flowing rivers for agricultural irrigation ## Footnote It was once the world's 4th largest body of inland water.
51
How can irrigation help?
It is possible to water areas of land that have become arid to try and improve the productivity of the soil. ## Footnote However, if water is not used sustainably then irrigation can cause water shortages and land degradation elsewhere.
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