Topic 7 - Hot Deserts Flashcards
Unit 1: Living with the Physical Environment (Section B - The Living World) (40 cards)
What is a desert?
An area of land that receives less than 250mm of rain annually
Where are hot deserts found?
30 degrees north and south of the equator
What are desert soils like?
Desert soils tend to be sandy or stony, with little organic matter due to the general lack of leafy vegetation. They are dry but can soak up water rapidly after rainfall. Evaporation draws salts to the surface, often leaving a white powder on the ground. Desert soils are not very fertile.
Where have the sand in deserts come from?
The break down of rock
What plants are found in a hot desert?
- Acacia Trees
- Ephemerals
- Cacti (e.g., Saguaro cactus, barrel cactus)
What animals are found in a hot desert?
- Fennec fox
- Kangaroo cat
- Perentie
- Thorny devil
- Desert tortoise
How have acacia trees adapted to live in hot deserts?
- Short, fat trunks, which can store excess water
- Pyrophytic (fire resistant)
- Long tap root (can be 50m into ground) vertical and horizontal to get as much water as possible
How have ephemerals adapted to live in hot deserts?
- Germinate only after seasonal rain
- Complete reproductive cycle quickly so hot conditions can’t affect them
How have cacti (e.g., saguaro cactus, barrel cactus) adapted to live in hot deserts?
- Succulent (store water)
- Spikes to deter consumers
- Spines rather than leaves, to reduce water loss by transpiration
- Waxy skin to retain water
- Widespread roots to collect water
How have perentie adapted to live in hot deserts?
- Shelters underground or in rock shelters; lie in the sun in early morning and late afternoons
- On very hot days, may shelter in shade or climb termite mounds or shrubs, to get off hot ground
How have fennec fox adapted to live in hot deserts?
- Produces little urine
- Large ears to spread out body heat
- Thick fur on soles of feel to protect from the heat of the sand
- Light coloured fur, which doesn’t absorb heat, but reflects it
How have kangaroo rats adapted to live in hot deserts?
- Produces little urine, as animals don’t find much water, so they must excrete only a little
- Don’t sweat/have oily skin, which reduces water loss
- Live in burrows during the day, to keep cool
- Don’t need to drink, as they get water from food
How have thorny devils adapted to live in hot deserts?
- Tiny grooves over the body to direct the moisture to the mouth
- Can change colour, and brown sports means it blends in with its surroundings
How have desert tortoise adapted to live in hot deserts?
- Live in burrows
- They are dormant (sleep) during the hottest part of summer (aestivation)
Where is the Thar Desert?
What are the opportunities for development in the Thar Desert?
- Farming
- Mineral Extraction
- Energy
- Tourism
What are the opportunities for development in the Thar Desert?
The Thar Desert is one of the major hot deserts of the world. It stretches across north-west India and into Pakistan. The desert covers an area of some 200000 km2 mostly in the Indian state of Rajasthan. It is the most densely populated desert in the world.
How is farming an opportunity for development in the Thar Desert?
Most of the people living in the desert are involved in subsistence farming. They survive in the hot and dry conditions by grazing animals on the grassy areas and cultivating vegetables and fruit trees.
Commercial farming, which has grown in recent decades, has been made possible by irrigation. The construction of the Indira Gandhi Canal in 1958, has revolutionised farming and crops such as wheat and cotton now thrive in an area that used to be a scrubby desert. Other crops grown under irrigation include pulses, sesame, maize and mustard.
How is mineral extraction an opportunity for development in the Thar Desert?
- Gypsum (used in making plaster for the construction industry and in making cement)
- Feldspar (used to make ceramics)
- Phosphorite (used for making fertiliser)
- Kaolin (used as a whitener in paper)
How is energy an opportunity for development in the Thar Desert?
- Coal: there are extensive lignite coal deposits in parts of the Thar Desert and a thermal energy plant has been constructed at Giral.
- Oil: a large oilfield has been discovered in the Barmer district which could transform the local economy.
- Wind: recently there has been a focus on developing wind power, a renewable form of energy. The Jaisalmer Wind Park was constructed in 2001. This is India’s largest wind farm.
- Solar: with its sunny, cloudless skies, the Thar Desert offers ideal conditions for solar power generation. At Bhaleri solar power is used in water treatment.
How is tourism an opportunity for development in the Thar Desert?
Desert safaris on camels, based at Jaisalmer, have become particularly popular with foreigners as well as wealthy Indians from elsewhere in the country. An annual Desert Festival held each winter is a popular attraction. Local people benefit by providing food and accommodation and by acting as guides or rearing and looking after the camels.
What are the challenges for development in the Thar desert?
- Water supply
- Inaccessibility
- Extreme temperatures
How are extreme temperatures a challenge for development in the Thar Desert?
- Working outside in the heat of the day can be very hard, especially for farmers.
- High rates of evaporation lead to water shortages which can affect people as well as plants and animals.
- Plants and animals have adapted to survive in the extreme heat. Some animals are nocturnal, hibernating in the cooler ground during the daytime. Livestock, such as cattle and goats,
need shade to protect them from the intense sun.
How is inaccessibility a challenge for development in the Thar Desert?
Due to the very extreme weather and the presence of vast barren areas there is a very limited road network across the Thar Desert. The high temperatures can cause the tarmac to melt and the strong winds often blow sand over the roads.
Many places are accessible only by camels, which is a traditional form of transport in the region. Public transport often involves seriously overladen buses
