🏜️ Physical: Hot Deserts Flashcards
What is mineral extraction?
The removal of solid material resources from the earth such as ores, coal, oil and precious stones.
Define hot deserts.
Areas of the world that have high average temperatures and very low precipitation.
What is desertification?
The process by which land becomes drier and degraded, as a result of climate change or human activities or both.
What is biodiversity?
The variety of life in the world or a particular habitat.
What is overgrazing?
Grazing too many livestock for too long on land, so it’s unable to recover its vegetation.
What is over-cultivation?
Exhausting soil by over-cropping the land.
What is appropriate technology?
Technology suited to the needs of the local people that combines cheap materials and is environmentally friendly.
What is soil erosion?
The removal of topsoil faster than it can be replaced, due to natural, animal and human activity. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient rich materials.
What is aridity?
The state or quality of being extremely dry.
What is Diurnal Temperature Range?
The difference between the maximum and minimum temps in that day.
What is a xerophyte?
A species of plant that has adaptations to survive in an environment with little water e.g. cacti
What is carrying capacity?
The maximum number of people an area of land can support before environmental damage.
What is the desert fringe?
Boarders of hot deserts. They support greater biodiversity and large plants. Semi-deserts.
What is the definition of a desert?
An area receiving less than 250mm of rainfall resulting in extreme aridity.
What are the physical characteristics of hot deserts?
- Extreme aridity (250mm< rainfall)
- Lack of biodiversity
- Barren (sparse vegetation)
- Rocky + sandy
- Above 40° during the day + sometimes cold during the night
Describe the location of deserts.
Deserts are found between 20° + 30° North and South of the equator (at the tropics)
Explain why deserts are where they are and how they’re formed.
- Insolation concentrates strongest on the equator making it hottest
- Low air pressure at the equator warms air and then clouds form with heavy rainfall when risen
- The air rises until it is eventually dry and heads N+S due to the Coriolis effect
- The cold, dense dry air then sinks forming deserts
Describe the soils found in the desert.
Sandy and rocky, typically about 1mm deep. They lack organic material and may have white powder on the top where salts are drawn to the surface by evaporation.
Why do deserts get very hot in the day and cold at night?
Lack of clouds means that temperatures during the day are very hot, and at night the lack of clouds means that there is nothing to keep the heat in.