hot deserts

Question 1

characteristics of hot deserts

Answer 1

30 degrees north/south of equator
rocky dry thin infertile soils

Question 2

how do hot deserts show interdependence

Answer 2

o Climate – very little rainfall with extreme temperatures.
o Soil – lack of nutrients and rainfall leads to dry, infertile soils.
o Plants – very little vegetation and plants have short life cycles.
o Animals – small, nocturnal mammals e.g. kangaroo rats, with very few birds.
o People – indigenous people grow a few crops near water sources in desert fringes.

Question 3

plant adaptations (4)

Answer 3

o Long root systems to absorb deep water supplies.
o Slower growing so less energy is required to make as much food.
o Waxy coating reduces transpiration from leaves.
o Cacti (succulents): Spines instead of leaves, minimises surface area and helps reduce water loss (and protect them).

Question 4

animal adaptations (2 animals)

Answer 4

o Fennec Fox: Large ears help release heat; produce little urine to save water; active at night to avoid heat.
o Camel: Large surface area to maximise heat loss; store fat in humps for energy; large/flat feet to avoid sinking in sand; triple eyelids and long eyelashes to keep sand out of eyes.

Question 5

4 developments opportunities of the western desert

Answer 5

mineral extraction, farming, energy, tourism

Question 6

how is mineral extraction a development opportunity for the western desert

Answer 6

Large underground water supply found in an ancient lava flow north of Ajo which is needed for mining.
Large-scale opencast mining for rich minerals underground (copper, uranium, gold).
Extremely valuable for the economy.

Question 7

how is energy a development opportunity for the western desert

Answer 7

 Strong insolation allows electricity to be generated at a low cost.
 For example, the Sonoran Solar Project (Arizona) will produce energy for 100,000 homes and requires 350 workers to build it.
 25 active oil production sites employ 100+ people and produce oil worth $50b.

Question 8

how is farming a development opportunity for the western desert

Answer 8

 High temperatures and sunlight provide great conditions for crop growth.
 Water was found for irrigation providing fertile, rich soils for large-scale commercial agriculture.
 For example, aquifers in Coachella Valley provide lush crops of vegetables and fruits like grapes (ideal for wine industry).

Question 9

how is tourism a development opportunity for the western desert

Answer 9

Tourism has brought plenty of foreign income from national parks (Grand Canyon) to major cities like Las Vegas (brings 40 million people/year).
Water projects in the lakes Mead and Powell such as sailing and powerboating brings 2 million tourists/year.

Question 10

how climate change a cause of these decertification

Answer 10

Causes of Desertification
Climate Change:
 Humans enhance the greenhouse effect which increases temperatures, increasing evaporation and making the land drier.
 Less rainfall means drier soils, so vegetation dies and there are less roots, leading to soil erosion.
 Contributes to increased risk of drought in the areas on the fringes of hot deserts.

Question 11

how removal of firewood a cause of these decertification

Answer 11

Removal of Fuel Wood:
 In developing areas, wood is used for cooking/building and there is a greater need for this.
 Roots of trees can’t hold the soil together, so it is more vulnerable to soil erosion.

Question 12

how overgrazing a cause of these decertification

Answer 12

Overgrazing:
 Too many cows, sheep, goats can destroy the vegetation.
 Bare soil is left exposed and becomes eroded/infertile.

Question 13

how overcultivation a cause of these decertification

Answer 13

Overcultivation:
 Farming too much without allowing soil to recover means it becomes infertile.

Question 14

how can planting trees reduce the risk of desertification

Answer 14

 Tree roots stabilise the soil which reduces soil erosion.
 Trees act as windbreaks, reducing wind erosion and the spread of deserts.
 Trees provide shade, reducing temperatures and evaporation rates.

Question 15

how can appropriate technology reduce the risk of desertification

Answer 15

 Using solar cookers or more efficient stoves to reduce the need for fuelwood.
 Rainwater can be collected on roofs to be used for irrigation.

Question 16

how can water and soil management reduce the risk of desertification

Answer 16

 Building rock walls/bunds that follow the contour of the land to capture the downward flow of water.
 Stops sediments from being washed off the slope by trapping them (good soil depth for cultivation).