Living World - Deserts

Question 1

what is intradependance

Answer 1

all parts of the ecosystem (climate, water, soil plants, animals and people) are dependant on one another and if one changes, everything will be affected

Question 2

why do hot deserts have a high temperature

Answer 2

they are found close to the equator so the sun’s rays are concentrated into a small area which leads to intense light and heat

found in areas of high pressure such as tropic of capricorn and tropic of cancer so there is little condensation so no clouds so all the sun’s heat energy reaches the surface easily

Question 3

why do hot deserts have low rainfall

Answer 3

in places such as the Sahara, it is caused by dry winds which happens as prevailing winds blow over the lands towards the sea causing the land to be dry as it hasn’t picked up any moisture yet

deserts near the western side e.g Kalahari are found by cold ocean currents and any wind which blows over the cold water causes cold air which can’t hold moisture and forms sea fog at the coast so by the time it reaches the land, it is dry

some deserts like Australian are inland and are sheltered by ridges of mountains and as wind blows up and over these mountains, the air cools and condenses and by the time they are blown inland, they are dry

Question 4

what is the area of land inbetween mountains called

Answer 4

rainshadow

Question 5

what are desert soils like

Answer 5

salty due to evaporation
shallow with coarse, gravelly texture
rocky, sandy, thin and grey
very dry due to little rain
infertile as little humus

Question 6

what is nutrient cycling in a desert

Answer 6

low rainfall causes slow decomposition and the biomass store is small due to lack of water and nutrients, the temperature is challenging as only few species a can survive and the soil is the largest store

Question 7

why are hot deserts near the tropics

Answer 7

due to atmospheric circulation as the air has risen at the equator then descends forming a ‘belt’ of high pressure causing a lack of clouds and high day temperatures as well as below freezing night temperatures as heat is quickly lost from the ground

Question 8

adaptations of Saguaro cactus

Answer 8

waxy cuticle layer to conserve water and protects from heat

pleats to store water

stem that can swell so cactus can take up and store as much water as it can during rainfall

needle like leaves to protect from predators

leaves are small spines with small surface area to limit water loss through transpiration

long and shallow root system allowing cacti to absorb as much water as possible

long deep roots to anchor the
plants in shallow soil and allows it to reach more nutrients deep underground

Question 9

adaptations of a camel

Answer 9

long eyelashes, hairy ears and closing nostrils to keep sand out of eyes, ears and nose due to frequent sandstorms

humps that store fat that can be metabolised for energy so they can last for several months without food

thick fur on top of body and thin fur elsewhere to provide shade and allows for easy heat loss due to temperatures reaching 40 degrees

thick lips so they can eat prickly plants so more food options

can drink 46 litres of water and can go for a week or so without water meaning when it rains, it can store enough water to last them till next period of rain

large, thick, flat feet to allow camels to walk on sand without burning their feet

Question 10

what are plant that can live in hot, dry conditions called

Answer 10

xerophytic

Question 11

what are the opportunities available in hot deserts

Answer 11

energy
mining
farming
tourism

Question 12

how is energy an opportunity in hot deserts

Answer 12

lots of renewable (wind and solar) and non renewable (coal and oil) energy resources are exploited in deserts e.g Thar

Question 13

how is mining an opportunity in hot deserts

Answer 13

the ores mined are used and exported all over the world e.g limestone as it is used for steel and cement, marble as it is used got construction and feldspar for ceramics
valuable resources of marble are quarried

Question 14

how is commerical farming an opportunity in hot deserts

Answer 14

the Indira Gandhi has enables the irrigation of 3500km² of land for the production of wheat, cotton and maize
it was built in 1958 and is 650km long
other crops such as mustard are grown are also sold for financial gain

Question 15

how is subsistence farming an opportunity in hot deserts

Answer 15

most people living in the Thar desert region use substance farming so people grow crops mainly for their own consumption
smalls areas of grass are used for cattle and local people forage fruits and berries
any additional food is sold at the local market
women wash up with sand and trees form good shelter for people and cattle

Question 16

how is tourism an opportunity in hot deserts

Answer 16

tourists are attracted to the picturesque landscape and is especially popular with people from Jaisalmer (a stop on the spice and silk route and population has grown by 1/3 recently)
there is lots of ecotourism which provides job opportunities which has created a multiplier effect
you can explore with jeeps or camel safari
120 species in the Thar national park

Question 17

what are the non renewable energy resources in the Thar desert

Answer 17

coal - there are lignite coal deposits in parts of the Thar desert and a thermal energy plant in the south

oil - large oilfield discovered in Barmer district which is predicted to transform local economy

Question 18

what are the renewable energy resources in the Thar desert

Answer 18

wind - 75 wind turbines constructed in 2001 are generating 60MW of energy near Jaisalmer which provides renewable energy to the Northern regional electricity grid

solar - long hours of cloudless sun is ideal for solar energy and in Bhaleri, solar energy is used to power water treatments such as desalination

Question 19

what is desertification

Answer 19

degradation of land so it becomes more desert like (drier, damaged and less fertile) and is caused by climate change, population growth, overgrazing, over-cultivation and soil erosion

Question 20

where is desertification a high risk

Answer 20

1/3 of the world’s surface is under threat but more prominent areas are those on the edges of deserts

Question 21

where is the Thar desert

Answer 21

North West India and stretches into Pakistan

Question 22

how big is the Thar desert

Answer 22

200,000 square kilometres

Question 23

what are the challenges in the Thar desert

Answer 23

water
inaccessibility
temperature

Question 24

explain how water is a challenge in the Thar desert

Answer 24

low precipitation levels and high evaporation levels so water is stored in tobas in remote areas

Question 25

explain how inaccessibility is a challenge in the Thar desert

Answer 25

the Thar desert is very vast and despite being highly populated, it has a limited road network

Question 26

explain how temperature is a challenge in the Thar desert

Answer 26

average temperature is 27 degrees but can exceed 50 degrees which makes it challenging for people such as farmers to work outside and it leads to rapid evaporation and water shortages