paper 1, section b, the living world Flashcards
1
Q
what is an ecosystem?
A
a natural system made up of plants, animals and the environment
2
Q
what are the two scales of an ecosystem?
A
- local small-scale = pond
- global scale = tropical rainforest
3
Q
what is the difference between biotic and abiotic?
A
biotic = living features (plants and animals)
abiotic = non-living environmental factors (climate, soil, water temp and light)
4
Q
what are producers?
A
producers convert energy from the environment (mainly sunlight) into sugars (glucose); the most obvious producers are plants that convert energy from the sun by photosynthesis
5
Q
what are consumers?
A
consumers get energy from the sugars produced by the producers; a pond snail is a good example of a consumer because it eats plants
6
Q
what are decomposers?
A
decomposers break down plant and animal material and return the nutrients to the soil; bacteria and fungi are good examples of decomposers
7
Q
what is a food chain?
A
a food chain shows the direct links between producers and consumers in the form of a simple line
8
Q
what is a food web?
A
a food web shows all the connections between producers and consumers in a rather more complex way
9
Q
what is nutrient cycling?
A
nutrients are foods that are used by plants or animals to grow; when plants or animals die, the decomposers help to recycle the nutrients making them available once again for the growth of plants or animals
10
Q
what are the two main sources of nutrients for nutrient cycling?
A
- rainwater washes chemicals out of the atmosphere
- weathered rock releases nutrients into the soil
11
Q
which environments of the pond ecosystem are important habitats?
A
- edge of pond
- banks
- centre of pond
- surface of pond
- pond margin
- pond bottom
12
Q
what are the impacts of change on an ecosystem?
A
- ecosystems can take hundreds if not thousands of years to develop
- if an ecosystem is to be sustainable it needs to be in balance
- if there is a change to one of the components it may well have knock-on effects for the rest of the ecosystem
13
Q
what causes change to an ecosystem?
A
changes to an ecosystem can occur naturally result from human activities; change can take place on different scales:
- global-scale changes, such as climate change
- local-scale changes, such as changes to a habitat, for example, when a hedge is removed
14
Q
what are natural changes and what effect do they have?
A
- ecosystems can adapt to slow natural changes with few harmful effects
- but rapid changes can have serious impacts
- extreme weather events like droughts can be devastating to ponds and lakes
- they could dry up in places, which changes the edge-of-pond environment
- plants will dry out and die; fish, starved of oxygen, might not survive
15
Q
what are changes due to human activities and what effect do they have?
A
- human activity can have impacts on ecosystems
- once a component has been changed it can have serious knock-on effects on the ecosystems
16
Q
what are some human activities?
A
- agricultural fertilisers can lead to eutrophication
- ponds may be drained to use for farming
- woods cut down destroying habitats for birds and affecting the nutrient cycle
- hedgerows removed to increase size of fields; habitats will be destroyed, altering the plant/animal balance
17
Q
what is an example of how change can affect an ecosystem?
A
Avington Park lake, Winchester, Hampshire
- a country estate close to Winchester
- the lake is of historical and ecological importance
- lack of maintenance, accumulation of silt and vegetation growth
- created an excellent habitat for birds but the view had been lost of the lake from the house
- 2014, restoration carried out, carefully done, view restored but new waterside habitats created to attract birds and waterfowl
18
Q
what does deciduous mean?
A
shed their leaves in winter to retain moisture
19
Q
what does coniferous mean?
A
cone-bearing evergreens, retaining their leaves to maximise photosynthesis during brief summer
20
Q
what are some global ecosystems?
A
- polar
- tundra
- desert
- mediterranean
- temperature grassland
- tropical grassland
- tropical rainforest
21
Q
what are features of tundras?
A
- from arctic circle to about 60-70 degrees north e.g. Canada, Northern Europe
- characterised by low-growing plants adapted to retain heat and moisture in the cold, windy and dry conditions
22
Q
what are features of deserts?
A
- roughly 30 degrees N + S of equator
- sinking air stops clouds forming, resulting in high day temps, low night temps and low rainfall
23
Q
where is classed as mediterranean?
A
- abt 40-45 degrees N of equator
- also isolated locations S of equator e.g. South Africa, Western Australia
24
Q
what are features of temperature grassland?
A
- roughly 30-40 degrees N + S of equator
- inland away from coasts
- hot, dry summers and cold winters
25
what are features of tropical grassland?
- between 15-30 degrees N + S of equator
- tropical climate in these low latitudes characterised by distinct wet and dry seasons
26
what are features of tropical rainforests?
- close to equator
- high temps and heavy rainfall associated with equatorial low pressure belt creates ideal conditions for plants to grow
27
what are features of polar ecosystems?
- arctic/antarctic
- cold air sinks at N + S poles, creating very low temps and dry conditions
28
what is the UK's natural vegetation like?
deciduous forest
29
where are coniferous forests suited to?
further north than UK e.g. Canada + Scandinavia since coniferous is more suited to colder climate
30
where are tropical rainforests found?
- in broad belt through tropics
- Central and South America
- Central Africa
- South East Asia
- Northern Australia
- on or around equator due to low pressure system
31
what is the climate like in tropical rainforests?
- warm and wet conditions
- found in equatorial zone
- temp is high and constant throughout year since sun is overhead most of the time
- high rainfall due to global circulation that causes areas of low pressure over equator; rising air = clouds = heavy rainfall
- rainfall varies throughout year
- distinct wet season (6 months) due to intense rainfall when low pressure area is directly overhead
- growing season all year round
32
how much rainfall do tropical rainforests get?
over 2000mm/year
33
what is the average temp of tropical rainforests?
27 degrees celsius
34
what are the soils like in tropical rainforests?
- surprisingly infertile
- most nutrients found on surface = dead leaves decompose rapidly in hot, humid conditions
- trees have shallow roots = absorb nutrients
- fungi transfer nutrients directly from air (nutrient cycling)
- heavy rainfall = wash away nutrients = leaching = leaves behind infertile red, iron-rich coil = latosol
35
what plants and animals live in tropical rainforests?
- supports largest no. of species of any biome
- 7% of worlds land mass (over 1/2 of all plant and animal species
- huge biodiversity
- birds live in canopy = feed on nectar
- mammals e.g. monkeys and sloths = well adapted
- animals like deer and rodents live on forest floor
36
how do plants and animals adapt to tropical rainforests?
- layers found
- majority live in canopy = most light
- forest floor = dark
- biotic factpors (fungi and bacteria) on forest floor have fragile but close relationship with abiotic factors (soil, temp, moisture)
- small changes = can have knock-on effects on entire ecosystem
37
what are the levels of the rainforest?
- emergent layer/canopy
- canopy layer
- understory/under-canopy
- forest floor
38
what are two species found in tropical rainforests?
- the sloth
- strangler fig
39
how are sloths suited to their environment (tropical rainforest)?
three-toed:
- camouflaged coats
- slow movements also help conceal from predators
- hold onto branches
- very sharp teeth
- long, sharp claws
- nine cervical vertebrae enables rotation of heads 270 degrees
- can raise body temp by basking
two-toed:
- can tilt heads 45 degrees backward to watch for predators
- can vary body temps from 75-91 degrees F
both:
- thick, dense coats to keep dry
- undercoat guarding skin; long, outer hairs hang down at angle as path for water to flow off
- extremely slow metabolism
- sleep for 15-20 hours daily
- go down to defecate once every 8 days
40
how are strangler figs suited to their environment (tropical rainforest)?
- start at top of tree and work down (seed dropped in nook at top of tree)
- uses debris collected as nourishment to begin with
- sends aerial roots down host's trunk to reach ground and take root
- fig gradually surrounds host, criss-cross roots around trunk and begins to strangle
- branches grow taller to catch sunlight
- invasive roots rob host of nutrients
- host dies eventually and leaves hollow, sturdy trunk of fig
41
what is deforestation?
- the cutting, clearing and removal of forest
42
what are main causes of deforestation in South America?
- mainly cattle ranching
43
what are main causes of deforestation in South East Asia?
- mostly land is converted to commercial plantations e.g. oil palm
44
what are main causes of deforestation in Africa?
- mainly food crops
45
outside the tropics, what are main reasons for forest clearing?
- settlement or agriculture
46
what are the causes of deforestation in Malaysia?
- logging
- commercial farming
- mineral extraction
- settlement and population growth
- energy development
- road building
- subsistence farming
47
why/how is forest in Malaysia cleared for logging?
- since 1980s Malaysia has been one of world's largest exporters of tropical wood
- around 80% of Borneo's rainforest destroyed for timber; mainly via clear-felling
- recently this has been replaced by selective logging (only fully grown trees cut down so young can grow)
48
why/how is forest in Malaysia cleared for commercial farming?
- Malaysia one of world's largest producers and exporters of palm oil (used in many food products)
- plantation owners receive 10-year tax incentives
- this business has resulted in huge areas of rainforest being cleared
49
why/how is forest in Malaysia cleared for mineral extraction?
- tin mining and smelting has resulted in forest loss
- in Borneo, drilling for oil and gas has started
- elsewhere, forest is cleared for mineral transportation to ports
50
why/how is forest in Malaysia cleared for settlement and population growth?
- people are moving away from overcrowded cities to live in less populated areas, clearing forest to create living space
- in the past, policy of transmigration involved new settlements being created for the urban poor
- between 1956 and 1980s, around 15000 ha of forest was cleared
51
why/how is forest in Malaysia cleared for energy development?
THE BAKUN DAM:
- in 2011, after 5 decades of delays, Bakun Dam in Sarawak started to generate electricity
- Asia's highest dam outside China (205m)
- reservoir flooded over 700km^2 of forests and farmland
- several more dams are planned to boost electricity supplies
- supplies electricity for industrialised peninsular Malaysia
52
why/how is forest in Malaysia cleared for road building?
- roads constructed for access to mining areas, new settlements and energy projects
- logging needs road construction to transport timber
53
why/how is forest in Malaysia cleared for subsistence farming?
- indigenous tribal people in rainforest practise subsistence farming
- traditionally, communities would hunt and gather food and grow food in cleared pockets of forest (small-scale and sustainable)
- one method of clearing land is 'slash and burn' = using fire to clear land; burning creates valuable nutrients that help plants grow
- the fires can grow out of control and destroy large areas of forest
54
how is deforestation an issue in Malaysia?
- one of world's highest rates of deforestation
- in 2018, equiv. of a football pitch cut down every 4 mins
- between 2000-2013, otal forest loss was area larger than Denmark
55
what are impacts of deforestation in Malaysia?
- economic development
- economic gains
- economic losses
- soil erosion
- loss of biodiversity
56
how is deforestation in Malaysia causing economic development?
- deforestation in many parts of world driven by profit
- short-term economic gains, long-term losses
57
how is deforestation in Malaysia causing economic gains?
- development of land for mining, farming and energy = lead to jobs directly and indirectly
- companies pay taxes to government which can be used to improve public services
- improved transport infrastructure opens up new areas for industrial development and tourism
- products like oil palm and rubber provide raw materials for processing industries
- hydro-electric power provides cheap and plentiful energy
- valuable minerals e.g. tin and gold for export; oil and gas extracted in Borneo
58
how is deforestation in Malaysia causing economic losses?
- pollution of water sources and increasingly dry climate may result in water shortages
- fires can cause harmful pollution; can burn out of control and destroy valuable forest
- rising temps could devastate some forms of farming e.g. tea, fruit, flowers
- plants that could bring huge medical benefits/ high profits may become extinct
- climate change could have economic costs
- no. of tourists attracted by rainforests could decrease
59
how is deforestation in Malaysia causing soil erosion?
- soil takes thousands of years to form; can be stripped away in hours if exposed to torrential tropical rain
- removal of soil by wind and rain called soil erosion
- tree canopy protects soil from full force of rain
- roots hold soil together
- deforestation means soil can easily become loose and erode away
60
where/when has soil erosion been a problem in Malaysia?
urban development in hilly areas of Penang Island and Kuala Lumpur city has involved widespread forest clearance; leading to severe soil erosion and causing frequent landslides
- in May 2011, after heavy rain, a landslide devastated an orphanage in Kampung Ganal, Kuala Lumpur, killing 15 children
61
what is biodiversity?
a measure of variety of plants and animals in a particular ecosystem
62
how is deforestation in Malaysia causing loss of biodiversity?
- deforestation destroys ecosystem and many habitats (ground and trees); reducing biodiversity
63
why is the biodiversity in the Main Range, Peninsular Malaysia important?
Main Range is an upland region stretching for 500km along backbone of Peninsular Malaysia
this region is important because:
- largest area of continuous forest left in Peninsular Malaysia
- forests particularly rich in biodiversity (>600 species)
- highland forests home to >25% of all plant species in Malaysia
- many undiscovered plants with medicinal qualities which could provide cures for diseases
64
how does the deforestation in Malaysia contribute to climate change?
- about 2/3 of Malaysia is tropical rainforest
- at global scale, deforestation reduces amount of CO2 absorbed by trees
- also increases CO2 emissions through burning
- increases effectiveness of greenhouse effect, promoting additional global warming/climate change
- at local scale, removal of trees reduces rates of evapotranspiration
65
what are rates of deforestation of tropical rainforests (gobal)?
- every 2 secs, area the size of a football field is cleared (over 1500 hectares/hour)
- tropical rainforests once covered over 15.5 million km^2 but now cover just over. 6.2 million km^2
- area of rainforest the size of China lost
- fastest rates of deforestation in Brazil and Indonesia (they account for 40% of deforestation)
- deforestation decreasing in Brazil but increasing in Indonesia
66
why is there high deforestation in Brazil?
- was mostly caused by small-scale farming but now mostly involves large landowners and big companies
- most rainforest been cleared for cattle ranching
67
how has deforestation been managed and reduced in Brazil?
since 2004, rate of deforestation fallen by nearly 80%
- government cracked down on illegal deforestation
- Brazil leading world in conservation + over half of Amazon is protected
- Brazil committed to reducing carbon emissions to tackle climate change
- consumer pressure not to use products from deforested areas has led to a decline in cattle ranching
68
what are three reasons why tropical rainforests should be protected?
1. biodiversity
- rainforests contain 1/2 of plants and animals in the world
- home to 1000s of different species
- some plants could become extinct before discovery
2. medicine
- around 25% of all medicines come from rainforest plants
- over 2000 tropical forest plants have anti-cancer properties
3. water
- rainforests are important sources for clean water; 20% of world's fresh water comes from Amazon Basin
69
who are the Achuar people in the Peruvian Amazon?
- a primitive tribe (around 11,000 people)
- live in small communities and rely on natural resources for buildings, fuel, food etc
- treat the TRF with respect as lives depend on it
- companies want permission to drill for oil in rich reserves (impact would be devastating)
- Achuar against this and stopped Talisman Energy in 2012 from exploration in that area
70
why do we need to maintain rainforests sustainably?
- ensure lasting resource for future generations
- allow valuable resources to be used without long-term damage to environment
71
how can rainforests be managed sustainably?
- selective logging and replanting
- conservation and education
- ecotourism
72
what is selective logging and replanting?
- most damaging is clear felling = cutting down of all trees in an area = destruction to an ecosystem
- selective logging = managed carefully = is completely sustainable; applied in Malaysia in 1977
73
how does felling work?
- 2 years before felling = pre-felling study to identify what's there
- 1 year before felling = trees marked for felling; arrows painted on trees to indicate direction of felling to avoid damaging other valuable trees
- felling = trees felled by licence-holders
- 3-6 months after felling = survey to check what has been felled; prosecution may result from illegal felling
- 5-10 years after felling = remedial and regeneration work by state forestry officials, replacement trees planted
- 30-40 years after felling = cycle begins again
74
how are conservation and education helpful to manage rainforests?
- done through national parks and nature reserves
- these can be for education, scientific research and tourism
- recently, large international businesses have shown support for conservation projects in exchange for carrying out scientific research or provision of raw materials
75
how is ecotourism helpful to manage rainforests?
- aims to introduce people to the natural world, to benefit local communities and protect environment for future
- income generated used by locals and governments to retain and protect rainforest trees, this is more sustainable than cutting them down
76
give a named example of conservation
GIVAUDAN
- Swiss perfume company who works with Conservation International
- aims to protect 148000 hectares of rainforest in Cairo Basin (Venezuela)
- local Aripao people encouraged to harvest and market tonic beans, which have a caramel-like smell
- warehouse where beans can be dried and stored built in 2012, improving their quality and value
77
what is a named example of conservation and education?
scientists in Sierra Leone: carbon sinks
- in 2008, the Gold Forest on Sierra Leone's southern border with Liberia became a protected national park
- park plays significant role in reducing global warming; acts as carbon sink by absorbing CO2 from air
78
what do international agreements aim to do?
help protect rainforests
79
hardwood forestry?
- the Forest Stewardship Council (FSC) is an international organisation that promotes sustainable forestry
- products sourced from sustainably managed forests carry the FSC label
80
what do the FSC do to help protect rainforests?
- tries to educate manufacturers and consumers about need to buy sustainable hardwood like mahogany
- aims to reduce demand for the rare and valuable hardwoods
81
debt reduction?
- some countries have borrowed money to fund developments
- to pay off these debts some have raised money from massive deforestation programmes
- recently, some donor countries and organisations have reduced debts in return for agreement that rainforests will not be deforested
- become known as 'debt-for-nature swapping'
82
how can desertification be reduced in hot deserts?
- water and soil management
- national parks
- tree planting
- appropriate technology
- magic stones
83
how does water and soil management help to reduce desertification?
- commercial farming in hot deserts often involves irrigation
- water from underground sources or rivers/canals can be sprayed onto crops/used to flood fields
- too much irrigation can cause problems + lead to salinisation
84
what is salinisation?
the high rate of evaporation in hot deserts can lead to a build-up of salts on the surface
85
what affect can salinisation have on soil/plants?
soil fertility is reduced and plants can die
86
what methods are local farmers in Australia encouraged to use to prevent soil erosion?
(water management is at the centre of attempts to combat desertification in Australia)
- ponding banks = areas of land enclosed by low walls to store water
- contour traps = embankments built along contours of slopes to prevent soil from being washed down during heavy rainfalls
87
what is an example of a water and soil management project?
Badia, Jordan
the Tal Rimah Rangeland Rehabilitation Project aims to reverse desertification from over-grazing in 1990s
- local people built low stone walls to stop water running down slopes after heavy rainfall
- this water used to irrigate newly planted Atriplex shrubs that are well adapted to semi-desert environments
- Atriplex hold soil together and provide grazing for sheep and goats
- as soil conditions improve, plants have started to grow, attracting birds and butterflies to the area
88
how do national parks help to reduce desertification?
hot desert areas at risk of desertification have been protected by making them into national parks
89
what are examples of a national park in the desert?
the Thar Desert, India:
- the Desert National Park created in 1992 to protect about 3000km^2 of desert and reduce risk of desertification
USA:
- the Zion National Park is 1 of 4 desert national parks in the USA; established in 1919 to protect a desert canyon near Las Vegas
90
what is an example of a tree planting project to help reduce desertification?
in the Thar Desert, a community-led project has planted 1 million trees to form a 'green wall' at Bikaner in Western Rajasthan with aim of reducing soil erosion by wind and reducing desertification
91
how does appropriate technology help to reduce desertification?
- many people living on the edges of deserts are poor
- appropriate technology involves using cheap, sustainable and available materials appropriate to local communities often experiencing low levels of economic development
- e.g. good quality and easily maintained hand tools are likely to be more appropriate than expensive diesel-powered tractors
92
how do magic stones help to reduce desertification?
- when rain washes down the hillside, the walls trap water and soil
- this has helped to increase crops by up to 50% and reduce desertification
93
what is an example of a magic stones project?
in rural parts of Burkina Faso lines of stone have been used to reduce soil erosion
using basic tools and trucks to transport the stones, local people have built low stone walls between 0.5m and 1.5m high along the contour sofa slopes
94
what are some causes of desertification?
- population growth
- over-cultivation
- removal of fuel wood (many people in dry areas rely on wood for fuel for cooking)
- overgrazing due to farmers becoming less nomadic; too many cattle or sheep eat plants faster than they re-grow
- climate change means that rainfall is reduced in areas that are already dry and temperatures increase so there is more evaporation
95
what is the effect of population growth on deserts?
- leads to need for more food
- increase in population and need for more homes puts pressure on land
can lead to more deforestation, over-grazing and over-cultivation
96
what is the effect of over-cultivation on deserts?
- over use of land to grow crops each year without allowing nutrients in ground to return leaves soil of poor quality where nothing can grow
- means new plants can't be grown and more soil erosion occurs
97
what is the effect of removal of fuel wood on deserts?
- cutting down trees for firewood and settlements has left soil unprotected
- as it's exposed, wind and rain washes nutrients away leaving soil infertile
98
what is the effect of overgrazing on deserts?
- farmers rely on water and land around them more
- means farmers don't regularly move to new fertile areas
- more soil erosion because no plants to hold soil together
- trampling by animals erodes soil
99
what is the effect of climate change on deserts?
- change in global climate has caused more droughts
- this damages animal's habitats and soil in many areas
- less water/higher temps = less plants, less plants = no roots to hold soil together
100
where is an example of desertification?
Badia, Jordan
101
what are the conditions like in Badia, Jordan?
- dry rocky desert in eastern Jordan
- average annual rainfall: <100mm
- summer temps = >40 degrees celsius
- lack of water is major issue for those living there
102
what has caused desertification in Badia, Jordan?
- nomadic Bedouin traditionally grazed sheep, goats and camels on rough, shrubby grassland
- influx of sheep from Iraq following Gulf War 1991 led to overgrazing and desertification
- this made land unproductive
- people moved away
- without vegetation, soil erosion also major issue
103
what is the name for the project to manage desertification in Jordan?
the Tai Rimah Rehabilitation Project
104
how is desertification being managed in Badia, Jordan?
- locals built low stone walls to stop water running down hills after heavy rain
- this water used to irrigate newly-planted Atriplex shrubs which are well adapted to these conditions
- shrubs hold soil together and provide grazing for sheep and goats
- as soil conditions improve, plants have started to grow, attracting birds and butterflies
105
what is the case study for opportunities for development in hot deserts?
- the Thar Desert which stretches across north-west India and into Pakistan
106
some information about the Thar Desert?
- one of world's major hot deserts
- north-west India and into Pakistan
- area of 200,000km^2 (most in Indian state of Rajasthan)
- most densely populated desert in the world
- sandy soils, not very fertile, little organic matter to enrich them, drain quickly so little surface water
- landscape = mainly sandy hills with extensive mobile sand dunes and clumps of thorn forest vegetation (mixture of small trees, shrubs and grasses
- low rainfall (between 100 and 240mm per year)
- summer temps in July can reach 53 degrees C
107
what are the opportunities for development in the Thar?
1. mineral extraction
2. tourism
3. energy
4. farming
108
how is mineral extraction an opportunity for development in the Thar?
desert region has valuable reserves of minerals which are used all over India and exported across world; most important minerals are:
- gypsum (used in making plaster for construction and cement)
- feldspar (used to make ceramics)
- phospherite (used for making fertiliser)
- kaolin (used as a whitener in paper)
there are also valuable reserves of stone in the region:
- at Jaisalmer the San limestone is main source of limestone for India's steel industry
- valuable reserves of marble are quarried near Jodhpur, to be used in construction industry
109
how is tourism an opportunity for development in the Thar?
- recent years, Thar's beautiful landscapes have become popular tourist destination
- 10,000s visit each year, many from Pakistan
- desert safaris on camels, based at Jaisalmer, have become very popular with foreigners and wealthy Indians from elsewhere in country
- annual desert festival held each winter is popular attraction
- local people benefit by providing food and accommodation, by being guides/rearing and looking after camels
110
how is energy an opportunity for development in the Thar?
Thar is rich energy source:
- coal; extensive lignite coal deposits in parts of Thar and thermal energy plant been constructed at Giral
- oil; large oilfield discovered in Barmer district which could transform local economy
- wind; recent focus on developing wind power (renewable), Jaisalmer Wind Park constructed 2001 (India's largest wind farm)
- solar; sunny, cloudless skies offers ideal conditions for solar power generation, at Bhaleri solar power is used in water treatment
111
how is farming an opportunity for development in the Thar?
- most people living in desert involved in subsistence farming
- survive in hot and dry conditions by grazing animals on grassy areas and cultivating vegetables and fruit trees
- commercial farming grown in recent decades, made possible by irrigation (construction of Indira Gandhi Canal in 1958 revolutionised farming), crops such as wheat and cotton now thrive in area that used to be scrubby desert
- other crops grown under irrigation e.g. pulses, sesame, maize and mustard
112
what are some challenges for development in the Thar?
1. extreme temperatures
2. water supply
3. accessibility
113
how are extreme temperatures a challenge for development in the Thar?
extremely high temps (summer = can exceed 50 degrees C), presents challenges:
- working outside in heat can be hard esp. for farmers
- high rates of evaporation lead to water shortages, affecting people, plants and animals
- plants and animals have to adapt to survive in extreme heat; some animals are nocturnal, hibernating in cooler ground in day, livestock need shade for protection
114
how is water supply a challenge for development in the Thar?
- water supply serious issue
- population growth + farming/industry development increased demand for water
- water = scarce resource
- low annual rainfall, high temps and strong winds = high evaporation rates
115
what water sources are there in the Thar?
- traditionally, drinking water for people and animals stored in ponds (natural + man-made)
- a few rivers/streams flowing through desert e.g. River Luni feeds marshy area called the Rann
- these streams are intermittent (only flow after rainfall) and most settlements are found by them
- some water can come from underground sources (aquifers) using wells, but this is salty and not very good quality
116
what is one solution to the water challenge in the Thar?
The Indira Gandhi Canal
117
how is the Indira Gandhi Canal a solution to water challenge in the Thar?
- main form of irrigation in desert
- source of freshwater has transformed extensive area of desert and revolutionised farming
- commercial farming e.g. wheat and cotton, now flourishes in area which used to be scrub desert
- two main areas to benefit from canal centred on cities of Jodhpur and Jaisalmer (>3500km^2 of land under irrigation)
- constructed in 1958, total length = 650km
- provides drinking water for many
118
how is accessibility a challenge for development in the Thar?
- limited road network due to extreme weather an vast barren areas
- high temps can cause tarmac to melt and strong winds blow sand over roads
- many places accessible only by camel
- public transport often involves seriously overladen buses
119
what are the environmental characteristics of hot deserts?
- less than 250mm of rainfall each year
- described as dry and arid
- found in dry continental interiors, away from coasts
- found in belts at approx 30 degrees N AND 30 degrees S (generally follow lines of Tropic of Cancer and Capricorn)
- desert climate formed by consistent high pressure; this is air that rose as low pressure at the Equator and now descends around the Tropics (global atmospheric circulation)
- lack of clouds and rain
- hot day temperatures and plummeting night temperatures
120
what are some examples of hot deserts?
- Sahara
- Mojave
- Atacama
- Namibia and Kalahari
- Great Sandy
121
what are some adaptations made by plants to survive in hot deserts?
- thick, waxy skin to reduce water loss/reflect heat
- large, fleshy stems to store water
- thorns and thin, spiky or glossy leaves to reduce water loss
- spikes protect cacti from animals wishing to use stored water
- deep roots to tap groundwater
- long shallow roots which spread over a wide area
- plants lie dormant for years until rain falls
122
how is the fennec fox adapted/suited to surviving in hot deserts?
- colour = reflects heat and good for camouflage
- fur = insulates during cold winter nights
- burrows = reduce water loss
- ears = dissipate excess body heat on hot days
- thick fur on feet = protection against hot sand
123
how is the saguaro cactus adapted/suited to surviving in hot deserts?
- spiny layer (2 inch thorns) = protection from animals
- waxy outer layer = reduce water loss (transpiration)
- stores water in its ribs
- shallow roots = quick absorption during rainfall
- spines have pads which absorb water and don't lose as much as leaves would
- ribs allow plant to change shape according to how much water it has
- can hold 5000 litres of water
