Paper 1 - Living World Flashcards
(127 cards)
1
Q
What is an ecosystem?
A
A natural system where living organisms (biotic components) interact with their non-living environment (abiotic components).
2
Q
What are the 2 types of components in an ecosystem?
A
- Biotic - such as plants and animals, bacteria and fungi.
- Abiotic - such as climate, water and soils.
3
Q
Do Ecosystems have to be a specific size?
A
Can be as huge as a rainforest or as small as a puddle.
4
Q
What is a producer?
A
Also known as an autotroph. Organisms that acquire their energy from sunlight, enabling them to produce food.
5
Q
What is a consumer?
A
An organism that gets its energy by eating other organisms.
6
Q
What is a decomposer?
A
An organism that gets its energy by breaking down dead material, e.g, bacteria and fungi.
7
Q
What is a Food Chain?
A
This shows the direct links between different organisms that rely on each other as a source of food - essentially who is eating whom. A simple, linear transfer of energy in an ecosystem.
8
Q
What is a Food Web?
A
This shows the complex hierarchy of plants and animals that rely on each other as a source of food within an ecosystem. Lots of food chains and how they interact.
9
Q
What is an energy pyramid/what does it show?
A
Shows how energy moves through an ecosystem.
Bottom of pyramid = high energy and low population, and these get smaller/lower the higher up the pyramid you go.
10
Q
What are the 4 stages/trophic levels of an energy pyramid starting at the bottom?
A
- Producers = make their own food (autotrophs), e.g, plants.
- Primary consumers = eat producers, e.g, herbivores.
- Secondary consumers = eat consumers, e.g, carnivores or omnivores.
- Tertiary consumers = also eat consumers, e.g, top carnivores or omnivores.
11
Q
What does a typical Gersmehl diagram/nutrient cycle look like?
A
There are three main nutrient stores, and several flows responsible for transferring nutrients between the stores, as well as inputs and outputs that provide and lose nutrients. There are also flows to and from the abiotic components, such as the rock.
12
Q
What typically happens in a nutrient cycle? (6)
A
- Dead material decomposes.
- Nutrients are released.
- Nutrients are taken up by plants.
- Plants eaten by consumers.
- Consumers die and decompose.
- Cycle repeats …
13
Q
How can the climate change to impact an ecosystem? (4)
A
- Extreme heat and lack of rainfall = drought.
- Atmospheric hazards/extreme events.
- Climate change.
- Unseasonal weather patterns.
14
Q
How can soils change to impact an ecosystem? (5)
A
- Lack of nutrient input (deforestation + drought).
- Salinisation - creation of infertile salt pans.
- Lack of ‘energy’ if food webs are compromised.
- Chemical contamination.
- water logging due to excess rain/lack of drainage.
15
Q
How can flora change to impact an ecosystem? (4)
A
- Deprivation of light or water.
- Invasive species - competition.
- Deforestation/clearance.
- Diseases, e.g Dutch Elm disease.
16
Q
How can fauna change to impact an ecosystem? (5)
A
- Deforestation => loss of food and habitats.
- Invasive species.
- Diseases.
- Hunting (over-exploitation).
- Removal/reintroduction of a species.
17
Q
What are the natural changes to an ecosystem? (4)
A
- Extreme weather events, such as flooding and drought.
- Fire caused by lightning strikes.
- Climate change and global warming.
- Spread of invasive species or introduction of alien species.
18
Q
Why were Grey Wolves removed from Yellowstone National Park?
A
Many human settlers feared the wolves predatory instincts and the welfare of their livestock, so when the wolves began eating sheep, bounty programmes began, eradicating the population of the wolves. By 1930s - Grey Wolves were eliminated.
19
Q
What impact did the loss of Grey Wolves have on the ecosystem of Yellowstone National Park? (3)
A
- Caused Elk populations to explode.
- Elks overgrazed entire park.
- Elk hooves eroded river banks, making rivers muddy and destabilised.
20
Q
What did the overgrazing of the elks mean for Yellowstone National Park? (4)
A
- mice/rabbits couldn’t hide
- bears no longer had berries to eat
- bees had less flowers to feed on
- songbirds had less trees
21
Q
What did the erosion of river banks by the elks mean for Yellowstone National Park? (7)
A
- loss of habitat
- less decomposition of organic matter
- less water temperature regulating
- less nutrient cycling
- beavers couldn’t make dams
- fish effected by dirty water
- many other aquatic species effected
22
Q
What is a biome?
A
A very large ecosystem, which is found across large areas of the earth.
23
Q
Where are tropical rainforests found?
A
Tropical rainforests cover about 2% of earths surface, yet they are home to over half of the world’s plants and animals. They are found in a broad belt close to the Equator from South America in the west, through West Africa to Southeast Asia and Australia.
24
Q
What is the Climate like in Tropical Rainforests?
A
- Tropical rainforests thrive in the equatorial climate, experiencing high temperatures (about 27°C) throughout the year and high rainfall (over 2,000 millimetres per year).
- This climate creates ideal growing conditions and accounts for the lush vegetation growth.
25
What is the water supply like in tropical rainforests?
* Most tropical rainforests experience a distinct wet season, with high rainfall totals lasting for several months.
* During this time, there is excess water on the ground, swelling local rivers and sometimes causing flooding.
* Water will soak into the soil, dissolving and transporting away nutrients - a process called leaching.
26
What are soils like in tropical rainforests?
* Rainforest soils are not very fertile.
* Nutrients are concentrated in the upper topsoil and are very quickly taken up by the plants as they grow.
* Intense leaching removes nutrients from the topsoil and redeposits them further down.
* This accounts for the red-coloured iron-rich soils (called latosols) that characterise tropical rainforest environments.
27
What are the characteristics of latosol/laterite soil? (7)
* Nutrient poor
* Poor water-retention
* Reddy brown colour due to iron oxides and derivatives
* Deep soil - can be up to 40m deep
* Thin/absent humus
* Can bake as hard as a brick if exposed to sun
* Doesn't respond to fertilisers well
28
Do people live in the amazon rainforest?
* Traditional tribes living in rainforests live in harmony with the natural environment, hunting and gathering only what they need to survive. This is a sustainable system.
* However, increasingly people from outside the local area are exploiting rainforests for commercial gain, chopping down trees for timber or to make way for ranching or commercial plantations.
* This is extremely harmful to the rainforest ecosystem and reduces biodiversity as habitats are destroyed.
29
How many species live in the rainforest?
As many as 30 million species of plants and animals live in tropical rainforests, over 50% of the worlds plant and animal species.
30
What are the 4 layers of a rainforest from top to bottom?
* Emergent layer
* Canopy
* Understory/Undercanopy
* Forest Floor
31
What conditions to plants and animals have to adapt to? (8)
* Amount of rainfall and its variation.
* Humidity.
* Low sunlight beyond canopy.
* Lack of nutrients in soils => difficult to root in, competition for nutrients, affects entire food web.
* Height of layers.
* Food competition for lots of animals.
* Temperature.
* Difficulty navigating through dense vegetation.
32
How is the adaptation of buttress roots purposeful for plants in the rainforest? (5)
* For emergent layer trees
* Wide roots, rather than deep so they spread along forest floor
* Ridges in roots for taking up water
* Stability
* Gives a large surface area to absorb nutrients and water that are accessible
33
How is the adaptation of stilt roots purposeful for plants in the rainforest? (2)
* Support lesser height trees
* Protrudes from higher up in the trees like crutches
34
How is the adaptation of lianas purposeful for plants in the rainforest? (2)
* Uses the tree as a base to climb up and coil around the tree - protective
* Climb to reach sunlight
* Vertical growth (narrow)
35
How is the adaptation of leaf angling purposeful for plants in the rainforest? (2)
* Not on top of each other so they don't shade other leaves
* Gives access to light
36
How is the adaptation of drip tips purposeful for plants in the rainforest? (3)
* Waxy cuticle and drip tips stops water damage
* Weight of water causes water to fall off
* Prevents water collecting and therefore bacteria/mould growth which would harm the plant
37
How is the adaptation of thin bark purposeful for plants in the rainforest? (3)
* Usually smooth
* Prevents other plants from growing onto it
* Thick bark = unnecessary and a better surface for vines
38
How is the Vanilla Orchid adapted to living in the rainforest?
* Climbs into the canopy to find more light.
* Thick waxy leaves to allow excess rainwater to run off, whilst retaining water needed within the leaves - important since the plant relies on aerial roots.
39
How is the Swiss Cheese Plant adapted to living in the rainforest?
Holes in leaves that;
* Enables water to runoff more quickly.
* Allows more sunlight to reach the leaves below.
* Stops the leaves being ripped by high winds in the upper canopy.
40
What are the 7 common adaptations of animals in the rainforest?
* Camouflage
* Mimicry
* Limited Diets
* Poison
* Nocturnality
* Reduction of Size and Stature
* Changing habitats
41
What is the adaptation of Camouflage for rainforest animals and what is an example?
* Colour that blends
* Shape that is unrecognisable to its predator
* Green eyed Tree frog
42
What is the adaptation of Mimicry for rainforest animals and what is an example?
* Adapt to look like something that is seen, rather than hide
* Katydid - looks like a leaf
* Lobster moth larvae - looks like scorpion
43
What is the adaptation of Limited Diets for rainforest animals and what is an example?
* Avoids food competition
* Toucans - beak allows it to eat nuts
44
What is the adaptation of Poison for rainforest animals and what is an example?
* Animals that can develop poison often develop bright colours to act as a deterrent
* Poison dart frog
45
What is the adaptation of Reduction of size and stature for rainforest animals and what is an example?
* Understory so dense
* Jaguar - grows less than 6 feet long and weighs around 200 pounds in rainforest => a lot smaller than other areas
46
What is the adaptation of Nocturnality for rainforest animals and what is an example?
* Reduces competition
* Other senses than sight become enhanced
* Bearded Pig
47
What is the adaptation of Changing habitats for rainforest animals and what is an example?
* Lives in canopy
* Spider monkey => tail
* Sloth => sleeps 15-18 hrs a day whilst hanging
48
What are Indigenous Peoples?
Distinct social and cultural groups that share collective ancestral ties to the land and natural resources.
49
How many indigenous peoples live in the world's rainforests?
Approx 50 million
50
How many groups of indigenous peoples are there in the Amazon rainforest alone?
400
51
What does Interdependence mean?
The dependence of two or more people or things on each other - mutual reliance.
52
What goods does the rainforest provide? (6)
* Native food crops (fruits and nuts)
* Wild meat and fish
* Building materials
* Energy from HEP
* Water
* Medicines
53
What services does the rainforest provide? (6)
* Air purification
* Water and Nutrient cycling
* Protection against soil erosion
* Wildlife habitats
* Biodiversity
* Employment opportunities - from farming to other opportunities
54
What Spices and foodstuffs are produced in rainforests? (2)
* The Vanilla orchid, which produces powerful little vanilla pods, grows in rainforests.
* Coffee + peppercorns can all be grown in a coexisting way.
55
What building materials can be found in rainforests? (2)
* Mahogany created huge deforestation as they grow alone as 1 tree in an area => paneling and to make furniture, boats, musical instruments
* Kapok => stuffing for pillows, mattresses, as insulation material
56
What is the Amazon Rainforest known as in terms of medicine?
The World's largest Medicine Cabinet.
57
What are some important uses of/interests in the rainforest in terms of medicine? (5)
* Indigenous tribes use barks, resins, roots and leaves as treatment.
* 120 prescription drugs come from plant sources.
* Less than 1% of TRF trees have been tested by western pharmaceuticals.
* 25% of active ingredients in cancer treating drugs come from organisms only found in the TRF.
* 100 pharmaceutical companies are researching the TRF.
58
What are 2 examples of medicines found in the Amazon rainforest and what do they do?
* Vampire bat Saliva => helps prevent heart attacks
* Novocain => from the Cocoa plant and can be used as a local anaesthetic
59
What is Biodiversity?
A measure of the variety of plants and animals in an ecosystem.
60
What is deforestation?
The cutting down of trees, often on a very large scale, so the land can be used for other profit making enterprises, as well as the high valued timber.
61
How is the rainforest valuable to people? (5)
* Resources
* Medicine
* Indigenous tribes
* Energy
* Employment => tourism, construction, farming and mining.
62
How is the rainforest valuable to the environment? (5)
* Water
* Biodiversity
* Climate
* Climate change
* Soil erosion
63
What are the economic gains of deforestation? (6)
* Development of land for mining, farming and energy leads to jobs.
* Companies pay taxes which can be used to improve public services (education + water supply).
* Improved transport infrastructure opens up new areas for industrial development + tourism.
* Products such as oil palm + rubber provide raw materials processing industries.
* Hydroelectric power produces cheap + plentiful energy.
* Minerals such as gold are very valuable.
64
What are the economic losses of deforestation? (6)
* Pollution of water sources and an increasingly dry climate may result in water shortage.
* Fires can cause harmful pollution - can burn out. of control, destroying vast areas of valuable forest.
* Rising temperatures could devastate some forms of farming such as growing tea, fruit and flowers.
* Plants that could bring huge medical benefits and high profits may become extinct.
* Climate change could have economic costs as people have to adapt to living in a warmer world.
* Number of tourists attracted by rainforests could decrease.
65
How can you manage tropical rainforests locally with selective logging and replanting?
* This involves felling trees only when they are fully grown, and letting younger trees mature and continue protecting the ground from erosion. Involves a 30-40 year cycle.
* However, not everyone adheres to this, and it takes a very long time meaning its possibly not meeting the demand.
66
How can you manage tropical rainforests locally by stopping illegal logging?
* Giving the remoteness of rainforest areas, illegal logging can easily go unnoticed. It is still happening on a large scale. However, satellites and drones are now helping to monitor this.
* Hard to monitor, and identify who's behind it - still a big issue.
67
How can you manage tropical rainforests locally with agroforestry?
* It involves combining crops and trees, by allowing crops to be grown in carefully controlled, cleared areas within the rainforest, and by growing rainforest trees on plantations outside the rainforest.
* Interferes with natural ecosystem balance - damages/moves wildlife habitats.
68
How can you manage tropical rainforests locally with replanting?
* A project in the Atlantic rainforest of Brazil (REGUA) has shown it's possible to recreate a forest cover almost like the original. This is done by collecting seeds from remaining patches of primary forest, growing the seeds into saplings in nurseries and then planting the saplings back into the deforested area.
* Lots of wildlife may have already evacuated and may not come back/takes a lot of time.
69
How can you manage tropical rainforests locally with ecotourism?
* Sustainable action.
* Scenery, wildlife, remoteness and culture are the main attractions.
* Aims to educate visitors and increase their understanding/ appreciation of nature and local cultures.
* It is small scaled and local, profits stay in local community and tries to minimise consumptions of non-renewable resources and the ecological impact.
* Can harm wildlife or disrupt it.
* Can be unsafe or un regulated.
70
How can you manage tropical rainforests locally by establishing biosphere reserves?
* A way of protecting part of rainforest by leaving it untouched except for research and plant breeding, etc.
* Protected core area is surrounded by a buffer zone in which only certain human activities are allowed, which causes little damage to ecosystem
* A lodge has been built within the forest, and tourists can stay there to learn about the environment.
* This is a successful example of using tourism to help protect the rainforest.
* Not enough of them to make a change/difference.
71
How can you manage tropical rainforests locally by making mining less destructive?
* Before the bauxite is exposed, a layer of top soil, together with ash from the burnt timber is removed and stored.
* Once the bauxite has been removed, the earth is replicated with native trees.
* The most of reforestation is $2500 per hectare, or 7% cost of the mine.
* Losing profits so lots of big companies will be unwilling to do it - has no appeal/incentive.
72
How can you manage tropical rainforests nationally? (3)
* Laws to protect areas or reserves.
* Laws to stop the abuse of the rainforest by developers.
* Establishing ecology or environmental studies as a compulsory part of the school curriculum.
73
What are some of the issues with managing tropical rainforests nationally? (4)
* Governments seem unwilling to enforce and monitor laws aimed at protecting/conserving the rainforest.
* There's lots of corruption in the way rainforests are treated, e.g, by illegal loggers and developers paying bribes.
* If people aren't willing to change, or have the ability/financial capability to they can't and won't.
* Few governments are willing to do anything that might slow down the rate of economic development. Citizens expect/want better living standards rather than new nature reserves.
74
What is the Convention on International Trade in Endangered Species (1973)?
* International strategy of managing tropical rainforests.
* Blocks the illegal trade in rare and endangered animals and plants.
* The illegal trade is still worth millions of pounds - unmanageable, CITES didn't really work.
75
What is the International Tropical Timber Agreement (2006)? (5)
* International strategy of managing tropical rainforests.
* Restricts the trade in hardwoods taken from the tropical rainforest.
* High prices paid for tropical hardwoods encourages large amounts of illegal felling - tends to happen in remote areas of the rainforest so often goes unnoticed by forestry officials.
* The 2006 agreement restricts trade in hardwood timber, to timber that has been felled in sustainably managed forests. All such timber has to be marked with a registration number.
* Illegal trade can't always be managed, and if hardwood loses value, other woods could become more valuable leaving you with the same issue.
76
How can you manage tropical rainforests internationally with debt reduction by HICs? (5)
* Most countries with tropical rainforests are NEEs or LICs, of which many may have large debts often as a result of overseas aid in the form of a loan.
* Schemes known as debt-for-nature swaps are arranged.
* E.g, in 2010 USA signed an agreement to convert a Brazilian debt of £13.5 million into a fund to protect large areas of tropical rainforest.
* These swaps are all part of what is known more widely as bet reduction, where some HICs agree to write off the debts of LICs.
* This only works if HICs are willing - not all will be, could also stop them from giving loans in the first place.
77
How can you manage tropical rainforests internationally with works of NGOs? (4)
* Charities that rely on donations and volunteers, e.g, WWF, Fauna and Flora International, World Land Trust. They operate anywhere in the world they think ecosystems are being seriously threatened.
* They can;
- promote the conservation message largely through education programmes in schools/colleges
- provide training for conservation workers/education
- provide practical help to make programmes more sustainable
- buy threatened areas and create nature reserves
* It's vital those involved in the exploitation and management of rainforest should be made aware of the consequences of what they do.
* This only works if the NGO gets funding, and educating people only makes a difference if the people act differently afterwards.
78
What does conservation mean?
Natural resources such as timber can still be used, but must be used sustainably.
79
What does protection mean?
The environment should be untouched and humans should not interfere, so ecosystems can find their own balance.
80
Where are hot deserts found? (2)
* Most of the world's hot deserts are found in the subtropics between 20 degrees and 30 degrees north and south of the Equator. The Tropic of Cancer in the northern hemisphere and Tropic of Capricorn in the southern hemisphere pass through most hot deserts.
* To the leeward side of mountains.
81
What is the aridity like in hot deserts? (2)
* The primary characteristic of a hot desert is its dryness or aridity.
* Hot deserts have total annual rainfall below 250 millimetres per year.
82
What are temperatures like in hot desert?
May reach 50 degrees Celsius in the day, and fall to below 0 degrees Celsius at night.
83
What are the 2 factors that form desert areas?
* The presence of high atmospheric pressure, and in turn lots of sinking air.
* Mountain ranges create rain shadows, which means there is lots of dry, sinking air on the leeward sides.
* Sinking air prevents the formation of cloud and rain, resulting in the very dry conditions.
84
What do desert landscapes look like?
Most deserts are rocky, desolate places with isolated thorny bushes and cacti.
85
What is the water supply like in the desert? (4)
* Water is in short supply for much of the year.
* When rainfall does occur it will often take the form of short torrential downpours, which can cause flash flooding.
* The high temperatures and low humidity result in very rapid evaporation.
* This means that plants and animals have to make the most of the water while it is available and store it for future use.
86
What is the soil like in the desert and why? (5)
* The main soil type in the desert is Aridisol, which has indistinguishable layers meaning it's poorly developed.
* It has a high content of mineral particles but little organic matter, and lots of bedrock causing it to be a thin soil.
* This is caused by the low plant productivity, which restricts soil-building properties of microorganisms that convert organic matter into the humus components of soils.
* Soils with low organic matter content have a low water-holding capacity - can't retain all water that falls on them.
* The intense evaporation of water from desert soils tends to bring dissolved slats to surface. The high surface content of sodium + calcium ions can lead to extensive salt pans where nothing/little can grow.
87
What does the Gersmehl diagram/nutrient cycle look like in hot deserts?
* The soil is the largest store proportionally.
* The decay pathway is the largest nutrient flow proportionally.
* We would anticipate weathering to be one of the biggest inputs.
88
How are Geophytes adapted to living in the desert + example?
* Tuberous subterranean organs, like leaf bases, roots and stems, grow underground.
* They are filled with stored foods, which provides for rapid growth with the return of favourable climatic conditions.
* E.g, Allium
89
What is CAMPhotosynthesis + example of plants who use it? (5)
* Plants usually absorb CO2 during the day through stomata in their leaves to perform photosynthesis.
* However, openings off the stomata also lead to the loss of valuable water.
* Some plants perform crassulacean acid metabolism (CAM) photosynthesis for carbon fixation.
* This means their stomata remain closed during the day, but open at night to absorb CO2 which is then stored and reconverted.
* E.g, Yucca.
90
How is the Saguaro Cactus adapted to living in the desert? (9)
* Xerophyte/Xerophytic.
* Waxy surface to reduce water loss and deter predators.
* Changes chemical composition of the water to make it less useful for others/toxic.
* Has spikes instead of leaves to deter predators and reduce water loss.
* Long, shallow, lateral roots to absorb surface water and anchor it into poor soil.
* Birds benefit from it as a home.
* Can store up to 5 tonnes of water.
* Pleats on trunk allow it to expand and contract according to water availability - can hold more water.
* During 4 weeks in summer it produces pollen. It blooms at night to pollenate and save water loss.
91
How are Ephemeral plants adapted to living in the desert? (3)
* Ephemeral plants don't live very long.
* When it rains they will grow rapidly and distribute their seeds before it dies.
* The new seeds then lie dormant awaiting the next rainfall.
92
How is the Kangaroo Rat adapted to living in the desert? (9)
* Able to go without water for long periods of time.
* Nocturnal.
* Covers seeds with sand in burrows for protection.
* Can carry lots of seeds at one time with cheek pouches.
* Large pink back legs which support the whole body.
* Sand coloured - camouflage.
* Lives in deep, underground burrows which deters protection and gives protection from the heat - also easily woken.
* Has small front legs which are used for shovelling seeds, not weight bearing.
* To protect itself from predators, it stamps its feet and kicks sand at the predator.
93
How is the Sand Cat adapted to living in the desert? (6)
* They can survive for weeks at a time without drinking water, as they instead obtain any moisture they need from their prey.
* Their tapered ears help protect it from windblown sand.
* They have soft, dense, thick coats which insulates them from the desert temperatures.
* Their big eyes and tapered ears help these creatures detect prey, such as small rodents, occasionally hares, birds, spiders, insects, and reptiles.
* They hunt by skulking close to the ground and using enhanced senses to detect pray.
* It has long, dense hairs that cover the soles of their feet which help it cope with the extreme temperatures of hot and cold sand.
* They are active during the day in winter and are nocturnal during the summer.
* To escape the extreme temperatures, they reside in burrows abandoned by foxes, or rodents, enlarging them as needed with their powerful but blunt claws.
94
How is the Camel adapted to living in the desert? (15)
* Long, thick double eyelashes to protect eyes from sandstorms.
* Have a meshy membrane and then eyelid.
* Thick eyebrows prevent sand getting in eye.
* Thick hump of fat for energy reserved if needed.
* Thick pads on chest, knees + feet, almost leathery to prevent exposure to heat of sand.
* Thick, rubbery lips help them to consume prickly plants.
* Healthy camel's body temp fluctuates from 34 degrees C to 41.7 => doesn't sweat and become dehydrated.
* Shaggy, thick, fur, sand coloured coat to keep warm at night and for camouflage.
* Can go 1 week without water and can drink up to 46 litres of water in one sitting.
* Can go several months without food.
* resistance to certain toxins/posions.
* Can close flexible nostrils during sandstorms.
* Broad based foot for traction on the sand.
* Ears covered with hair even on inside to keep sand out.
* Concentrates urine to excrete less water.
95
How have people adapted to living in deserts + example? (3)
Tribes such as the Bedouin in Jordan have adapted their lifestyles to cope with the harsh conditions:
* They live in large open tents, which keep them cool during the day but
warm at night.
* Traditionally, food is cooked slowly within the warm sandy soils.
* Head scarves (keffiyeh) traditionally worn by men to provide protection from the Sun, warmth at night, and can cover the mouth and nose during sand storms.
96
How biodiverse are hot deserts? (4)
* Hot deserts are considered to have low levels of biodiversity.
* This reflects the low rainfall and lack of available water.
* However, rich biodiversity does exist in pockets where water is present, for example close to an oasis where underground springs emerge at or close to the ground surface.
* Rich biodiversity can also exist close to seasonal lakes or streams.
97
What is desertification?
Land degradation, usually on the fringes of hot deserts.
98
How many people does desertification affect?
An estimated one billion people live in areas at risk from desertification.
99
Is desertification a natural process?
No it's caused by humans.
100
How much land is lost every year to desertification?
12 million hectares.
101
How is population pressure a cause for desertification? (4)
* There is an increasing population in some arid areas, which means the land is more intensely farmed, thus degraded causing desertification.
* Also leads to removal of fuelwood. Removal of too many tree branches for fuel wood can lead to those trees dying.
* People need more water, taking it away from the land.
* Economic pressure for cash crops, that aren't always suited to the environment.
102
How is location a cause for desertification? (2)
* Fringes of deserts are more vulnerable areas; due to Hadley cell, and possibly being on leeward sides of mountains => sinking air. Inland away from oceans its drier.
* Certain areas have different societal norms linked to overpopulation.
103
How are natural events a cause for desertification? (3)
* Periods of extended drought.
* Sandstorms.
* Heavy rains/flash floods.
104
How is climate change a cause for desertification? (3)
* Results in drier conditions + unreliable rainfall. On average it rains less now than it did 50 years ago.
* Rising temperature also means more evaporation which results in less water for the land, and may even change seasons for crops.
* El Niño => warming of the oceans - causes oceans top be low pressure instead of high pressure. This means the ocean air isn't feeding the pressure of the land, resulting in it raining in the ocean not the land.
105
How is soil erosion a cause for desertification? (3)
* When vegetation has been destroyed, soil is exposed to wind and rain, making it more vulnerable to erosion.
* Exposure to water leads to leeching, which strips away nutrients and harms crops.
* Wind erosion blows away top soils which is where the nutrients are.
106
How is poor farming a cause for desertification? (5)
* Hyper productive farming/over-cultivation, which is a result of the need to produce more food, can lead to soil exhaustion. This means the soil will turn to dust and become infertile.
* Chemical fertilisers and the overuse of pesticides can also harm the soil.
* Poorly managed irrigation systems.
* Can be difficult for some farmers to learn about the changes they need to make, due to literacy levels.
* Some men are leaving rural areas for cities to find work. This leaves women left with the land, without the time, experience, knowledge or resources to care for it properly.
107
How might Badia's annual rainfall of less than 150mm cause desertification? (2)
* Doesn't provide for crops.
* People don't have enough water so they have to take it from the ground.
108
How might Badia's summer temperatures cause desertification? (3)
* Often exceed 40 degrees C.
* High temperatures are bad for crops and increase evaporation.
* Harder working conditions.
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How might climate change in Badia cause desertification? (3)
* Made rainfall more sporadic and difficult to predict.
* Leads to periods of drought and possibly flood which harms the soil.
* Hard for farmers to cope.
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How might overgrazing in Badia cause desertification? (3)
* Much of the land has been grazed by Bedouin nomads who herd sheep, goats and camels.
* Overgrazing of land and loss of vegetation.
* Allows for soil erosion.
111
How might Badia's population cause desertification? (3)
* Population in the area has increased sharply since Gulf War of 1991.
* More demand for food, water and crops.
* Economic pressures, i.e, cash crops.
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How might a loss of vegetation in Badia cause desertification? (4)
* Led to large amounts of soil erosion.
* Wind erosion.
* Leeching/water erosion.
* Destroys soil and crops.
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How can National Parks reduce desertification?
* In some parts of the world hot deserts have been protected from further desertification by making them into national parks.
* These national parks have rules regarding farming practices, developments, water extraction and environmental protection.
* Creating rules and regulations allows the national parks to have greater control over the factors that cause desertification.
114
What are 2 methods of water management to reduce desertification?
* Ponding banks - areas of land enclosed by low walls to store water and stop it washing soil away. E.g, in Badia Jordan they also utilise Atriplex Shrubs.
* Contour traps - embankments built along the contours of slopes to prevent soil being washed away during heavy rainfall.
115
How do Magic Stones/Bunds work at reducing desertification? (4)
* Lines of stones are shifted using basic tools and trucks, and arranged along the contours of a slope.
* Local people have built these low stone walls, between 0.5m - 1.5m high.
* They trap water and soil when it rains.
* Increased crops by up to 50% whilst reducing desertification.
116
What are the advantages of tree planting for reducing desertification? (4)
* Binds the soil together.
* Provides shade.
* Provides grazing for animals.
* Provides fuelwood.
117
What are the advantages of planting the Prosopis cineraria - desertification? (5)
* Provides shade and moist growing conditions for plants.
* Plenty of foliage and seedpods for animals to eat.
* Strong wood for building materials.
* Good quality firewood.
* Roots to stabilise sand dunes.
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What is appropriate technology?
Simple technology and equipment that local people will be able to use. It involves methods and materials that are suitable to their level of development.
119
What is Salinisation?
A build up of salts on the surface when the water evaporates. Salinisation reduces fertility and kills plants.
120
How, in Badia, Jordan, have they successfully used water and soil management to reduce desertification in 4 stages?
* Local people built low stone walls that stops water running down slopes after heavy rainfall.
* They keep this water and use it to irrigate newly planted Atriplex shrubs that are well adapted to semi-desert environments.
* Atriplex shrubs hold the soils together and provide grazing for sheep and goats.
* As soil conditions improve, plants start to grow, attracting birds and butterflies to the area.
121
How have the UN tried to reduce desertification on a global scale? (4 main stages)
United Nations Decade for Deserts and the Fight Against Desertification - January 2010 to December 2020 - promoted action to protect the dry lands. UN directive to government;
1. Advised direct action by government.
- effective early warning, assessment and monitoring
- integrate environmental issues into the mainstream of decision making at all levels.
2. Engagement of public and private sectors.
- get businesses involved with the issue.
3. Develop economic opportunities and markets.
- aid farmers in finding other types of work, as they're likely struggling.
4. Promote Women's Empowerment.
- help them to learn how to cultivate and use the land when men go looking for work in urban areas.
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What is the Green Wall - Africa?
* The African Union's proposed 'Green Wall' is a plan to plant a wall of trees across the entire Sahel region, running from the Atlantic Ocean to Indian Ocean. Includes; Senegal, Chad, Sudan and Ethiopia etc.
* It will be decades before the Greens Wall reaches maturity.
123
What are the benefits of the African Green Wall? (5)
* Offers hope for sustainable development among communities.
* Makes physical environment more secure.
* Generates work for desperately poor communities in all the Sahel countries.
* Brings about political co-operation in the region.
* Might reduce conflict, and the number of refugee camps, which unfortunately contribute to desertification.
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What are the drawbacks of the African Green Wall?
Climate change projections suggest increased aridity may threaten the survival of the trees in the long term.
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What is the African Wall aimed to have done by 2030? (3)
* Restore 100 million hectares of currently degraded land.
* Sequester 250 million tonnes of carbon.
* Create 10 million jobs in rural areas.
126
What is agroecology and how might it reduce desertification on a local scale? (3)
* Farming choices and lifestyles adapted to the soil/environment.
* E.g, aerating the soil or other traditional methods suited to crops.
* Can mean growing different crops to take different nutrients from the soil.
127
What are Toyola stores and how might it reduce desertification on a local scale? (3)
* Small fire used in local areas for cooking.
* Use less fuel than a traditional fire.
* Less dangerous.
* The store's are compact, more practical and safer for the environment.
