Hot deserts

Question 1

physical characteristics of hot deserts

Answer 1

• aridity
• heat
• landscapes
• infertile soils

Question 2

where do most of the deserts lie

Answer 2

between 20 and 30 degrees north and south of the equator. the tropics run through most hot deserts

Question 3

what is the definition of a desert

Answer 3

an area receiving less than 250mm rainfall a year

Question 4

why are deserts arid and how does that affect the extreme fluctuations in temperature from day to night

Answer 4

due to the sinking air at these latitudes causing high atmospheric pressure which prevents the formation of cloud and rain

this means no cloud coverage hence heat can easily escape at night and beat down in daytime

Question 5

interdependence between plants and soils in hot deserts

Answer 5

plants relying on soil for nutrients to grow

soils relying on plants for restocking those nutrients through their dead matter and fixing chemicals from the air into it. Plants also shade the soil from the sunlight so that it can retain more water and they also bind the soil together preventing erosion and leaching of nutrients

Question 6

interdependence between animals plants and soils

Answer 6

intricate food webs are easy to disrupt, and all start with some sort of plant producer that is first eaten

Question 7

how are humans interdependent with plants, water and soils

Answer 7

humans require them for crops and food

humans replace plants with afforestation and conservation schemes which helps to fix water and nutrients in the soil

Question 8

how do plants adapt to the conditions of hot deserts

Answer 8

• extensive root networks to absorb maximum rainfall
• rapid life cycles, germinating flowering and setting seed in a matter of days (triggered by the only occasional rainfall
• small, linear leaves or needles with a waxy resin to reduce evapotranspiration

Question 9

how do animals adapt to the conditions of hot deserts

Answer 9

• many are nocturnal so they can hunt in the dark as well as large eyes to help them see in low light
• often live in burrows to keep cool in daytime
• large ears to enable heat loss
• highly efficient kidneys to produce little urine
• no perspiration
  (camels)
• wide feet for walking on soft sand (no sinking in)
• long eyelashes and thin nostrils to protect from blowing sand

Question 10

where can rich biodiversity be found in deserts

Answer 10

near water sources such as an oasis or seasonal lakes and streams

Question 11

comment on hot deserts’ biodiversity

Answer 11

they have very low biodiversity due to low rainfall so not many plants have the necessary adaptations to survive the lack of water

Question 12

what is our case study of a hot desert

Answer 12

western desert in the USA, which is made up of the Mojave, Sonora, and Chihuahua and goes through states California, New Mexico and and Arizona

Question 13

what are the four development opportunities in hot deserts in the western desert USA

Answer 13

• mineral extraction
• energy
• farming
• tourism

Question 14

what opportunities for mineral extraction are there in case study area

Answer 14

rich reserves of copper, uranium, and coal

developments have been limited by environmental concerns including the possibility of mining uranium in the grand canyon

Question 15

what opportunities are there for energy (case study)

Answer 15

• solar
• oil in Arizona, owned and operated by indigenous people
• HEP from Lake Mead

Question 16

what opportunities are there in farming (case study)

Answer 16

• irrigation has enabled commercial farming to thrive

such as peppers, vegetables and grapes (for wine)

Question 17

what opportuinites are there in tourism (case study)

Answer 17

• people visiting the national parks and wilderness areas for landscapes and solitude
• lake mead and lake powell are popular for water sports
• Las Vegas is an entertainment centre

Question 18

what are three challenges of developing the area (case study)

Answer 18

water supply
inaccessibility
extreme temperatures

Question 19

how is water supply a challenge in the area (case study)

Answer 19

water transfer from the colorado river has been the supply since the Hoover Dam was built but this is running lower and water demand continues to soar

Question 20

how is inaccessibility a problem in the area (case study)

Answer 20

the low density population has lead to a lack of surfaced roads through the desert although there have been some efforts to amends this such as Route 66

Question 21

how are extreme temperatures a challenge in the area (case study)

Answer 21

• work outside is very difficult during the day
• it leads to high rates of evaporation and then water shortages

Question 22

what is desertification

Answer 22

where land turns into desert

Question 23

what are the six causes of desertification

Answer 23

climate change
over grazing
population growth
over-cultivation
removal of fuel wood
soil erosion

Question 24

how does climate change cause desertification

Answer 24

it disrupts the normal patterns of rain and causes more droughts which is bad for the most fragile ecosystems in the world

Question 25

how does overgrazing cause desertification

Answer 25

vegetation is stripped from an area so the soil is left bare and vulnerable to erosion

Question 26

how does population growth cause desertification

Answer 26

demand for food increases, land put under pressure, soil erosion

Question 27

where in the world is desertification a problem

Answer 27

in the semi-arid areas near deserts

Question 28

how does overcultivation lead to desertification

Answer 28

soil loses nutrients, becomes dry and dusty, soil erosion

Question 29

how does soil erosion cause desertification

Answer 29

soil left bare to be baked by sun, when rainfall comes it washes over the surface instead of sinking in, eroding it and washing away the fertile topsoil, leaving behind very infertile sub-soil

Question 30

what are three strategies that can reduce the risk of desertification

Answer 30

• water and soil management
• tree planting
• appropriate technology

Question 31

how does water and soil management reduce the risk of desertification and what does it involve

Answer 31

involves strategies such as bunds (low rock walls) to trap the soil that has been eroded then carried by the water and also to spread and distribute the water flow along the bunds sideways. the trapped soil can then be cultivated

reduces soil erosion

Question 32

what is an example of tree planting to reduce desertification`

Answer 32

the great green wall launched by the African Union, planting trees along the edge of the sahara desert

Question 33

what is appropriate technology

Answer 33

it is for the specific people that will use it and the place they will use it in, affordable, and sustainable

Question 34

why are bunds an example of appropriate technology

Answer 34

• makes use of local materials, basic tools and transport, and is based on a very simple idea
• doesn’t need specialist skills to build so can make use of the community

Question 35

apart from bunds, what is another example of appropriate technology

Answer 35

efficient cooking stoves that burn smaller amounts of fuel, reducing the amounts of wood needed