The Living World Flashcards
(191 cards)
1
Q
What is an ecosystem?
A
a place where living organisms interact with their environment
2
Q
What is an organism?
A
a living thing
3
Q
What does biotic mean?
A
the biotic part of an ecosystem is the living part
4
Q
What does abiotic mean?
A
the abiotic part of an ecosystem is the non living part
5
Q
What is a producer?
A
an organism that uses sunlight to produce its food
6
Q
What is a consumer?
A
an organism that eats another organism
7
Q
What is a decomposer?
A
an organism that gets its energy from breaking down dead material
8
Q
What is a food chain?
A
a diagram that shows what eats what
9
Q
What is a food web?
A
a diagram that shows overlapping food chains
11
Q
What happens in the nutrient cycle?
A
- Nutrients stored in the soil are taken up by plant roots and stored in the plant.
- Eventually the plant dies and falls to the ground as litter.
- The nutrients are then stored here.
- Decomposers break down the litter for energy so the nutrients go into the soil.
- Where they are stored again so new plants can take them up.
12
Q
What is an example of a small scale ecosystem?
A
Hedgerow
(location: UK)
13
Q
What are abiotic components of a hedgerow?
A
- Temperate (not extreme) climate
- Rich fertile soils / brown earths
14
Q
What are the biotic components of a hedgerow?
A
- Producers: Hawthorn (the hedge) + blackberry bushes
- Consumers: Ladybirds, thrush, blackbird, sparrow hawk, caterpillars, badgers, mice
- Decomposers: worms
16
Q
What are examples of how organisms survive in the hedgerows?
A
- mice use the hedgerow to hide from their predators
- the sparrow hawk is a secondary consumer and eats mice
- the thrush is a primary consumer and eats blackberries
- the blackbird nests in the hedge and also finds it’s food here
- hawthorn is a producer, it gets energy from the sunlight and nutrients from the soil
- caterpillars are primary consumers that eat blackberries
- nutrients found in the fertile brown earth are there because composers like bacteria break down the litter
19
Q
What is a biome? (examples)
A
A global scale ecosystem
e.g. (hot) desert, tropical rainforest, temperate (deciduous) forest, tundra, taiga (boreal/coniferous forests), tropical grasslands, polar desert
20
Q
Where are (hot) deserts found globally?
A
On and around 30° North and South of the equator
e.g. Northern Africa, Sahara, Central Australia, Southwest USA
21
Q
What is the climate of (hot) deserts?
A
Hot – 30° North and South – rays concentrated over small area
Dry – high-pressure so air sinks – clouds dont form
22
Q
What are the soils like in (hot) deserts?
(summarised)
A
- called Aridisols – thin, not very fertile as little
- few plants so few nutrients go into the soil in nutrient cycle
23
Q
What is the vegetation like in (hot) deserts?
A
- Little vegetation as lack of water
- Shrubs and cactus adapt to lack of water - can absorb water in stem
24
Q
Where are tropical rainforests found globally?
A
On and around the equator
E.g. north of South America – Amazon, Southeast Asia, central Africa
25
What is the climate of tropical rainforests? (why?)
**Hot** – close the equator – rays concentrated over small area, roughly stays the same temperature at 27°C
**Wet** – low pressure so air rises – clouds form – more than 2000 mm of rain
26
What is the soil like in tropical rainforests? (summarised)
- soil is not very fertile as nutrient cycle is very rapid due to ideal conditions for growth
- nutrients washed away by water
27
What is the vegetation like in tropical rainforests? (summarised)
- 15 million species - high diversity - hot and wet conditions – perfect for growth
- Tall trees (up to 40 metres)
- Buttressed bases for support
- Evergreen with large, dark green, leathery leaves
28
Where are temperate (deciduous) forests found globally?
40° - 60° North
e.g. western Europe
29
What is the climate of temperate (deciduous) forests?
Mild – 60° North and South – rays spread out over large surface area
Wet – low pressure so air rises – clouds form
30
What are the soils like in temperate (deciduous) forests?
Brown earths – fertile
31
What is the vegetation like in temperate (deciduous) forests?
- Trees e.g. ash and oak - deciduous
- Fertile soils and mild climate means lots of growth
- Loose leaves in autumn to prevent water loss
- Bluebells grow in spring when sunlight gets to forest floor
32
Where are tundras found globally?
On and around the Arctic Circle
E.g. North Russia , North Canada
33
What is the climate of tundras?
Little rain – high pressure – often falls as snow
Cold temperatures - average 10°C
34
What are the soils like in tundras?
Soil frozen – permafrost – stops regrowth – only top metre not – soil off and wet – little evaporation
35
What is the vegetation like in tundras?
Low species diversity – not many plants – climate not good for growth
- Low-lying to protect from wind
- short growing season
- leathery leaves to prevent water loss
36
Where are taigas (boreal/coniferous forests) found globally?
45-57° North
37
What is the climate of taiga (boreal/coniferous forests)?
- Cool to cold in winter
- warmer in summer
- Rain in summer
38
What are the soils like in taiga (boreal/coniferous forests)?
Deep litter layer as little decomposition – too cold
39
What is the vegetation like in taiga (boreal/coniferous forests)?
- Evergreen trees
- Needles to prevent water loss as times of year when little water
e.g. Black and white spruce
40
Where are tropical grasslands found globally?
On edges of deserts
e.g. East of Africa, Mexico
41
What is the climate of tropical grasslands?
- Hot all year round – not much rain and it tends to fall in one season
- Often has periods of drought and fires
42
What are the soils like in tropical grasslands?
Porous thin layer of humus
43
What is the vegetation like in tropical grasslands?
Grasses and shrubs – can lack water at times
44
Where are polar deserts found globally?
Very high latitudes
North/South pole
45
What is the climate of polar deserts?
Cold – 90° north and south – rays spread out over large surface area
Dry – high pressure air sinks – no clouds
46
What are the soils like in polar deserts?
very little soil
mainly bare rock
47
What is the vegetation like in polar deserts?
occasionally plants grow in cracks in rock
e.g. arctic poppy
48
What is biodiversity?
the variety of different species living in an ecosystem
49
Why is biodiversity important?
ASK MS BOARDMAN + look at exam paper
50
Describe the soils in a tropical rainforest.
- They are red as they contain lots of iron.
- They are deep but not fertile as the heavy rain washes away the nutrients.
- They have a deep litter layer because they have an all-round growing season so plants are constantly dropping their leaves.
- They have a thin humus layer because the leaves decompose quickly and the plants take up the nutrients quickly.
51
Describe the vegetation in a tropical rainforest.
- Vegetation grows in distinct layers, in each layer the plants are adapted to the conditions so there are lots of different species.
- They are evergreen – even though they look deciduous because they grow all year round so there are lots of plants and animals because there is high primary productivity.
52
What is the nutrient cycle like in a rainforest?
[link](https://docs.google.com/document/d/1zOtegseaUiDpX5QgjlrIsW0QXh4qOYVgzGQqu2R1vrs/edit)
53
What are the 4 ways leaves are adapted to a tropical rainforest?
- drip tips
- large surface area
- waxy surface
- arrangement
54
What are the 5 plant adaptations to the rainforest?
- leaves
- roots
- trees
- epiphytes
- lianas
55
How are leaves adapted to the rainforest?
- because of heavy rainfall, plants need to shed water to avoid growth of fungus and bacteria
- because bacteria likes hot and wet climate so leaves would rot – thats why they have **drip tips + waxy suface**, so the bacteria doesn't grow otherwise it would decrease photosynthesis on the leaves
- **Arranged at different angles** so a plant avoids shading each other
- **large surface area** to get most sunlight which it uses to photosynthesise
- high levels of biodiversity to there is competition for light
56
How are roots adapted to the rainforest?
**buttress roots**
- trees have very shallow roots
- these roots cannot support tall trees
- so buttress roots are massive and give the tree stability
- they don't actually go into the soil or take up nutrients
57
How are trees adapted to the rainforest?
- **very tall** to reach the sunlight
- **fan shaped leaves** good for catching sunlight and water
- These leaves are segmented so excess water drains away
- also arranged at different angles so avoids shading
- **bark isn't thick – it's thin and smooth** because it makes it harder for other plants to grow on it and it doesn't need to keep moisture in so is thin
58
What are epiphytes?
- plants that grow on other plants so can reach the sun
- plants which live on the branches of trees high up in the canopy
59
How are epiphytes adapted to the rainforest?
- Plants that grow on other plants to reach sunlight
- Start at the top
- Grows on trees to take advantage of the sunlight in the canopy
60
What are lianas?
woody vines that have roots in the ground but climb up the trees to reach the sunlight
61
How are lianas adapted to the rainforest?
- vines that climb up trees and drape over them
- Roots on the ground and climb up high (climb up from the bottom) to reach the sunlight
62
What are the 4 animal adaptations to the rainforest?
- camouflage
- creating niches
- living in trees
- being nocturnal
63
How does camouflage help animals adapt to the rainforest?
- **camouflage** is used to avoid becoming prey
- e.g. **sloths** moves very slowly and spend time upside down on trees making it harder to spot them
- **blue-green algae grows on its fur** giving the sloth a greenish colour making it more difficult for predators to spot
🦥
64
How does creating niches help animals adapt to the rainforest?
- because there are so many animals competing for food, many animals have adapted by learning to eat a particular food eaten by no other animal - this is called **creating niches**
- e.g. **toucans** have adapted by developing **long, large bills** so they can break open hard nuts that other animals can't
🥜🦤
65
How does living in trees help animals adapt to the rainforest?
- many animals and insects in the rainforest live in the trees and never set foot on the ground
- the animals use the tall trees and understory for shelter, hiding places from their predators, and a source of food
- e.g. monkeys 🐒
66
How does being nocturnal help animals adapt to the rainforest?
- many animals have adapted to a nighttime life in order to survive
- e.g. **Amazon tree boa** avoid predators that are active during the day like birds of prey and primates by **sleeping during the day**
- at night they hunt other nocturnal animals like rodents using special infrared receptors located in their mouth
- hunting at night also means there's less competition for food
🐍
67
What is the location of the Amazon rainforest?
- The Amazon Rainforest is in the North of South America.
- Most of it is in Brazil, although the edges of it spread into countries including Peru, Bolivia and Suriname
68
What are the 7 causes of deforestation?
- Logging -> trees are used for e.g. furniture, fuel, charcoal
- Road building -> brings supplies + provides access to areas
- Mineral extraction -> mining
- Energy development -> high rainfall creates ideal conditions for hydroelectric power (dams)
- Settlement + population growth
- Cattle ranching
- Commercial farming -> arable
69
What is logging (deforestation)?
- Trees like mahogany and teak are used for furniture + other uses
- smaller trees are used for fuel, pulped or made into charcoal
70
What is road building (deforestation)?
- Roads bring supplies + provide access to new mining areas, new settlements + energy projects
- In Brazil, the trans-Amazonian highway stretches for some 4,000 km through the rainforest
71
What is mineral extraction (deforestation)?
This is a major cause of deforestation in many countries
In Brazil, minerals such as gold bauxite and copper are mined extensively, causing huge scars in the landscape + polluting rivers
72
What is energy development (deforestation)?
High rainfall creates ideal conditions for hydro-electric power and there are several large dams + reservoirs
- In Brazil the Belo Monte dam (opened in 2019) is a huge hydro-electric power complex, the 2nd largest in the country
- In damming the Xingy River, a tributary of the Amazon, 40,000+ hectares of rainforest have been flooded
73
What is settlement + population growth (deforestation)?
- Settlements have developed to service the developments in the Brazilian rainforest
- Such as farming + mineral extraction
- This has led to a growth in population
74
What is commercial farming (deforestation)?
- Land is cleared for commercial farming
- In Brazil, cattle ranching accounts for 80% of deforestation
- Soybeans, palm oil + sugar cane are the major crops
75
What are some general facts about Rainforests?
- Rainforest are home to 2/3 of the worlds plant species
- Rainforest cover 6% of the Earth's surface
- Rainforests are home to 30 million species
- 12-15 hectares of forest are lost each year (36 football field a minute)
76
What are some facts about the Amazon Rainforest?
- The Amazon covers 5.5 million km² (about 40% of South America)
- The Amazon River is the 2nd longest river on Earth
- Over 20% of the worlds oxygen comes from the Amazon alone
- 350+ indigenous groups live in the Amazon
- On average, 160 inches of rain falls in the rainforest each year
- In the Amazon Rainforest, there are 4,100 miles of rivers
77
How does deforestation lead to a loss of biodiversity?
- Deforestation reduces biodiversity.
- This affects not only plants and animals in the rainforest, but also humans.
- For **species** in the rainforest, the loss of biodiversity can disrupt food chains and interdependent relationships.
- For **humans**, rainforests can be useful for medicine, food and more, so with loss of biodiversity, humans have less of this.
78
How does deforestation effect the local climate of an area?
- Because of deforestation, there is less interception from trees.
- This means that there is less evapotranspiration which leads to there being lest moisture in the atmosphere.
- So there are then less clouds so less rain, which means that the local climate is drier.
- In 2005, the Southwest Amazon experienced drought conditions
79
How does deforestation affect the global climate of an area?
- During deforestation, less CO2 is absorbed, so there is more CO2 in the atmosphere
- Slash and burn is also often used to deforest and burning put CO2 into the atmosphere.
- This means that the greenhouse gas layer gets thicker.
- Deforestation contributes to 17% of greenhouse gas emissions.
- This traps more heat from the Sun.
- This means global temperatures are rising.
- So global temperatures have risen by about 1°C.
80
What is the impact of soil due to deforestation?
- Because of deforestation, there are fewer roots to hold soil together that would previously keep the soil in place.
- There is also no canopy to protect soil from heavy rain.
- So the soil is washed away.
- This is called **soil erosion**.
81
How does deforestation create river poisoning?
- Mercury is used to extract gold from gold mines.
- Mercury is toxic.
- When it rains, the mercury gets washed into rivers.
- This pollutes the water + the fish in the rivers.
- In Tapajós river, 90% of fish had a trace of mercury in them.
- This leads fish to die, so there is less food for the indigenous people who eat the fish.
- The poisoned fish that indigenous people do eat can make them poisoned too.
82
What are positive economic and social impacts of deforestation?
- Large companies make profits from selling items that they got from deforestation.
- This provides jobs and wealth and improves quality of life.
- The companies pay taxes to the government, which the government can then invest into infrastructure and to improve development.
- Selling goods such as gold and cobalt can increase foreign exchange.
83
What are negative economic and social impacts of deforestation?
- The livelihoods of some local people are destroyed.
- For example rubber tapping requires trees.
- Deforestation can cause loss of animals + plants they rely on for a living.
- Eco-tourism also suffers with deforestation.
- Deforestation also creates conflict
84
What has happened to the number of endangered species in Brazil?
They have increased from 200 in 1989 to 600 in 2008
85
How many tons of carbon does the Amazon rainforest store?
100 billion
86
Name a tribe who have been moved because of deforestation
The Guarani Tribe
87
How much money did Brazil make from trading cattle in 2009?
$6.9 billion
88
How many people do Vale mining company employ in Brazil?
154,000
89
How many tons of topsoil are lost to erosion due to soil production in Brazil?
55 million
90
What percentage of CO2 emissions globally come from the deforestation of the Amazon?
20%
91
What are positive effects of deforestation?
- jobs for many people
- selling things can lead to foreign exchange
- economic growth
- new homes for people
- hydro-electric power
- improves Q of L
- increased taxes for gov.
- wealth for locals + companies
92
What are negative effects of deforestation?
- increased CO2 - adds to global warming - global increase in temperature
- can displace indigenous communities from their homes + they can lose their job/food source
- loss of biodiversity
- soil erosion
- locally increases drought
- river poisoning
- poor health
- conflict
93
What goods can people get from the rainforest?
- food crops (bananas, vanilla etc)
- wild meat + fish
- timber
- energy from hydroelectric power
- medicine
94
What services does the rainforest provide for people and the environment?
- climate regulation
- water + nutrient recycling
- protection against soil erosion
- wildlife habitats
- biodiversity
- employment opportunities
95
What is the value of the tropical rainforest to people?
- resources
- medicine
- indigenous tribes
- energy
- employment
96
How are tropical rainforest useful for resources?
- Tropical rainforest are rich in reserves of wood, nuts + fruit as well as minerals
- Every day items such as bananas, cocoa + sugar come from tropical rainforests along with spices such as vanilla + cinnamon
97
How are tropical rainforest useful for medicine?
- About 25% of all medicines come from rainforest plants
- Over 2,000 plants have anti-cancer properties
- Less than 1% of rainforest plants + trees have been tested by scientists for their medicinal properties
98
How are tropical rainforests useful for the indigenous tribes in a tropical rainforest?
- Thousands of people live in the rainforest, with their lives depending on maintaining a healthy ecosystem
- E.g. the Actuar tribe in Peru numbers over 11,000, living in small communities relying on the rainforest for food, building materials and fuel
99
How are tropical rainforest useful for energy?
- High rainfall totals in rainforests create the potential for hydro-electric power
- Electricity can provide much-needed light + power for local people
- Local micro-hydro schemes can serve isolated communities
100
How are tropical rainforests useful for employment?
- Rainforests can provide employment opportunities in tourism for guides or stewards
- Other opportunities exist in construction, farming + mining
101
What is the value of the tropical rainforest to the environment?
- Water
- Biodiversity
- Climate
- Climate change
- Soil erosion
102
How are tropical rainforest useful for water?
- Rainforests are important sources of freshwater
- About 20% of the worlds freshwater comes from the Amazon basin
103
How are tropical rainforest useful for biodiversity?
- Tropical rainforests contain 50% of the worlds plants + animals
- Including thousands of different species
104
How are tropical rainforest useful for climate?
- Known as the 'lungs of the world', rainforests contribute 28% of the worlds oxygen
-Moisture emitted through transpiration feeds into the water cycle + prevents the climate becoming too dry + hot
- Evaporation of water from rainforest helps to cool the air (heat is extracted from the air during the process of evaporation)
105
How are tropical rainforest useful for reducing climate change?
- Rainforests absorb carbon dioxide (greenhouse gases) from the atmosphere, acting as a carbon sink
- this helps to offset global warming
106
How are tropical rainforest useful for reducing soil erosion?
Rainforests shelter + bind together the tropical soils, preventing harmful soil erosion, which can silt up rivers + reservoirs
107
What is sustainability?
Development that meets the needs of the present without compromising the ability of future generations to meet their own needs
this has to happen economically, socialy and environmentally
108
What is an NGO?
A non-governmental organisation (NGO) that is independent from the government like a charity
e.g. Oxfam
109
What are the 6 rainforest management strategies?
(use the acronym)
**IC CASE** (I "see" 👁 case 💼)
**I**nternational agreements
**C**onservation + education by NGOs
**C**onservation swaps/debt reduction
**A**groforestry
**S**elective selling/logging replanting
**E**co-tourism
110
What is selective logging + replanting?
choosing certain trees to cut down e.g. older trees and/or a few of each type of tree and then replanting after
111
How is selective logging + replanting sustainable?
- keeps the stability + structure of the rainforest
- maintains biodiversity
- allows indigenous communities to still live there
- this with international agreements can generate wealth
112
What are international agreements?
- Countries all sign up to do the same thing
- International agreements on the uses of tropical hardwoods and logging.
- The International Tropical Timber Agreement (ITTA) was set up in 2006 to "promote the expansion and diversification of international trade in tropical timber from sustainably managed and legally harvested forests and to promote the sustainable management of tropical timber producing forests".
- 71 countries have signed up to the agreement sponsored by the United Nations.
113
How are international agreements sustainable?
- creating a global market for trees by selective logging
- encourages more selective logging
- generates wealth + jobs in the future
114
What is agroforestry?
Growing crops in the forest and not cutting the forest down
115
How is agroforestry sustainable?
- creates jobs while also maintaining the structure of the forest
- allows people to live + work in rainforest + make more money while keeping the forest in tact
116
What is conservation + education by NGOs?
charities educating people why they might buy sustainable products
117
How is conservation + education by NGOs sustainable?
it creates awareness do people are more likely to buy goods from agroforestry or selective logging etc.
118
What are conservation swaps/ debt reduction?
when wealthy countries relieve debts of poorer countries in exchange for using the money for conservation projects
119
How are conservation swaps/ debt reduction sustainable?
- builds relationships with countries
- conservation projects generate wealth
- investing in conservation will help decrease deforestation
120
What is ecotourism?
Encouraging tourism that is sustainable as it doesn't damage the environment while also generating wealth
121
How is ecotourism sustainable?
- builds in clearings so doesn't cut down trees
- creates jobs and wealth
- maintain structure of forest
122
What is the climate in a hot desert?
- Deserts are seasonal in a lot of the months of the year, the temperature is very high, peaking at around 35°C
- Here the rainfall is extremely low and almost none.
- In the other months of the year it is colder, with the lowest temperature being 12°C.
- The rainfall is still extremely low.
- All year round the rainfall is far below 10 mm
123
Why do temperatures drop below freezing at night in a hot desert?
Because of high pressure, there are little/no clouds, this means that at night, there is nothing to trap heat and so the temperatures are very cold at night.
124
What are the soils like in a hot desert? (more detailed)
- Desert soils, or Aridisols, tend to be thin, sandy, rocky, and grey.
- Due to the climate, they are very dry, and quickly absorbs any water that falls.
- The crusty surface is known as hardpan.
- When water evaporates from the surface it may leave a deposit of salts.
- There is not much vegetation, so consequently there is little humus (nutrient rich decomposed vegetation), but plants may be nourished by minerals
125
What are the plant adaptations in a hot desert?
- Some plants have horizontal root systems, just below the surface.
- Some plants have long taproots (7-10 m deep) to reach groundwater.
- Some plants store water in their roots, stems, leaves, or fruit (these are called succulent).
- Small leaves or spines, glossy and waxy leaves all reduce water loss.
- Seeds can stay dormant for years, but can germinate quickly when it rains.
126
What is an example of vegetation and it's adaptation in a hot desert?
**Saguaro cactus**
Stores five tons of water which can last them five months of drought
127
What are the animals with adaptations in a hot desert?
- Kenyan sand boa
- Sand cat
- Nocturnal Arabian death scorpion
- Fennec fox
- Camels
128
How is a Kenyan sand boa adapted to a hot desert?
- comes out in the cold mornings + the cold night, as it is too hot during the day
- nostrils and eyes are placed high on the head so that they can remain free of debris while they are burrowed in the sand
129
How is a Sand cat adapted to a hot desert?
They have padded paws with tough hairs to protect their feet from hot sand and help them stand on sand without falling through
130
How is a Nocturnal Arabian Death Scorpion adapted to a hot desert?
- They only come out at night
- They get water from eating insects
- If there is little food they can slow down metabolism to only eat three insects per year
- it doesn't drink, but instead it absorbs moisture from the small insects that it eats
- They have an exoskeleton which reduces water loss
131
How is a Fennec Fox adapted to a hot desert?
- They are camouflaged: sand colour fur
- They have a small pointed nose to prevent water loss. They have big ears to cool itself down.
- They have soft padded paws to walk on sand easily
132
How is a Camel adapted to a hot desert?
- They have two sets of eyelashes to protect from the Sun + sand.
- They. have padded hooves.
- Their hump stores fat which can be turned into water
133
What are some examples of desert ecosystem interdependence?
- because of high pressure, there are little clouds so there is barely any rain, this means that the vegetation has to adapt to have little water (e.g. long roots to collect lots).
- because there is very little vegetation, the soil is not very fertile because nutrients aren't being recycled.
- because there are very few water sources, animals have to adapt to survive of other animals and very little water
134
Why do deserts have low levels of biodiversity?
- Animals have to be very specially adapted as there is little food or water.
- It is difficult to grow plants, which makes the soils very infertile so no more plants grow
135
What is a case study for a hot desert?
The western desert
136
What is the location of the western desert?
- The western desert is found in the south-west of USA.
- It is made up of three deserts; the Mojave desert, the Sonoran desert and the Chihuahuan desert.
- It covers five states of the USA.
- Including Arizona, Utah, Nevada, California and New Mexico.
137
What are the challenges of developing hot desert environments?
1. extremely hot temperatures
2. Very little water
3. Sand is difficult to build on
138
What is carrying capacity?
The number of people who can be supported by an environment
139
Why might the carrying capacity of the land vary from place to place in the western desert?
- The edges of the desert are easy to access.
- This means that many people can live on the edge of the desert because construction on the edge of the desert can be easily done so houses can be built + more people can live there
- Also because there are rivers or aquifers in some areas so water for drinking can be easy access so more people can live there
140
What is a fact about the temperatures in the Death Valley in the Western desert?
Temperatures in the Death Valley can reach 50°C in July
141
What is tourism like in the western desert? (include facts)
- It is the most important source of income for people in the western desert.
- There is all-round good weather
- there are 4 national parks
- Death Valley has 2 million visitors per year.
- It creates jobs for locals, as tourist spend money, so creates foreign exchange, so wealth for locals increases.
- Activities include horse riding, camping and hiking
142
What is energy like in the western desert? (include facts)
- Solar energy can be used due to cloudless skies
- 360 jobs created to build solar power plants
- This powers 100,000 homes
- There are 25 oil production sites
- Over 100 people work in oil production which is worth $50 million
- However oil is non-renewable so jobs will eventually not be available so is a short-term opportunity
143
What is mining like in the western desert? (include facts)
- Uranium and copper are still mined in this region
- Generates wealth for companies where these are sold and creates jobs for locals
- However sometimes is dangerous and isn't long-term as resources such as oil, uranium and copper will eventually run out
144
What is farming like in the western desert? (include facts)
- Farming makes $1 billion a year
- They get water from the Colorado river
- They farm vegetables, lemons and grapes
- It creates a 1/3 of jobs in Imperial river
- However, jobs are seasonal and low paid
145
What are some facts about population in the Western desert?
- The population of Phoenix has doubled since 1980 to 4. 5 million people
- Population growth in the desert state is 3% per year which is greatest in USA
146
How are there challenges with inaccessibility in the Western desert?
- Much of the area is mountains – road building is hard
- Few tarmacked roads
- Extreme temperatures – dangerous if car breaks down
147
What changes are being made in the Western desert to reduce the challenges of inaccessibility?
- Railways were built to key settlements like Las Vegas
- Better roads have been laid – like Route 66 connects Chicago to California
- New bus routes
- Major cities in the desert to have airports (40 million travel to Las Vegas each year)
148
How are there challenges with climate in the Western desert?
- extreme high temperatures
- Mojave Desert's death valley - temperatures are approx 50° in July
- reaching survival limit for plants
149
What changes are being made in the Western desert to reduce the challenges of climate?
- Flat roof to help collect rainwater
- Small houses to reduce sunlight and keep temperatures low inside
-> these were used before air-conditioning
But now there are:
- Whitewashed walls to reflect sunlight and keep buildings cool
- Sports pitches replaced with fake grass
- People have adopted drought resistant 'desert landscaping' in their gardens
150
How are there challenges with water in the Western desert?
- Water shortages
- 30 million people depend on water from the Colorado river. But population growth will mean the water will have to be stretched further
- Water security is threatened by climate change
- The combination of changing climate + the region's rapid population growth means that even greater water scarcity is expected in the future
151
What changes are being made in the Western desert to reduce the challenges of water?
- Canals to irrigate fields
- Dams to store water
- E.g. Hoover Dam stores the equivalent of two years' river flow
- With the Glen Canyon Dam, the 2 dams and reservoirs smooth out the Colorado's flow through the year and remove its flood pleat peaks and bring additional benefits to many other places + communities
- Reservoir water is piped along aqueducts - this feeds homes, farms + golf courses
- This water transfer has costs but also benefits
152
What is desertification?
The process by which land becomes drier and degraded, as a result of climate change or human activities, or both
153
What is over cultivation?
Excessive use of farmland to the point where productivity falls due to soil exhaustion or land degradation
154
What is overgrazing?
Grazing too many livestock for too long on the land, so it is unable to recover its vegetation
155
What is arid?
Lack of moisture, especially having insufficient rainfall to support most trees or woody plants. It is extremely dry, has low precipitation and high rates of evapotranspiration
156
What are climate changes?
Long-term changes in the earth's climate, especially a change due to an increase in the average atmospheric temperature
157
What is drought?
When there is abnormally low rainfall for an extended period of time
158
What is famine?
A widespread, serious shortage of food – in the worst cases it can lead to starvation + even death
159
What is food insecurity?
Being without reliable access to a sufficient quantity of affordable, nutritious food
160
What is a fragile environment?
An environment that is both easily disturbed and, difficult to restore if disturbed
161
What is soil erosion?
The wearing away with the topsoil by the action of wind or water
162
What is the case study for desertification?
The Sahel
163
Where is the Sahel?
Below the Sahara desert
164
What are some countries where the Sahel is?
Mauritania, Mali, Niger, Chad, Sudan (+ others)
165
How has the average rainfall of the Sahel changed?
Since 1970, the Sahel had below average rainfall.
This is likely due to climate change.
166
What are natural causes of desertification?
Changes to rainfall patterns due to a complex interaction between the atmosphere, oceans, cryosphere, biosphere and land. This is due to natural long-term climate change.
167
What is the main driver of the human causes of desertification?
Population growth
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What are the (human) causes of desertification?
- **Climate change** is making temperatures hotter + rainfall less reliable and more variable
The **population** of semi desert areas is increasing, this means that:
- Animals are grazed at higher stock number to feed the people, so animals eat more of the vegetation in the area (**overgrazing**)
- People collect more firewood to keep warm at night, or, for cooking, so there is a loss of forest cover (**deforestation**)
- Land is farmed more intensively, this farming takes nutrients out of the soil and removes the natural vegetation (**over cultivation**)
**SO** the amount of natural vegetation decreases
And the cycle of desertification happens...
169
Why does overcultivation contribute to desertification?
Over cropping land can exhaust soil fertility and soil becomes infertile and cannot sustain vegetation
170
Why does firewood removal result in desertification?
Trees get cut down which means less evaporate transpiration so less cloud cover
171
Why does over cultivation, overgrazing and firewood removal result in soil erosion?
There is less vegetation, so the land is more exposed to the wind and rain, there are also no roots to keep the soil together so soil erosion occurs
172
Why does soil erosion then contribute to desertification?
Top fertile layer is washed away resulting in infertility and land becoming degraded
173
What is the cycle of desertification?
- The amount of natural vegetation decreases
- There are no plants or leaves so to intercept rain + soil is left exposed to the hot sun
- The sun bakes the soil and it cracks
- When it rains, the rainwater runs over the surface of the soil rather than soaking in
- This means that soil can often be washed away
- The soil is degraded, losing fertility + structure
- Soil is worn out/poor quality and it is harder to grow crops + natural vegetation
- So the amount of natural vegetation decreases
And the cycle continues...
174
What are the overall causes of desertification? (short answer for conclusion)
Overall, desertification is caused by a **complex interplay** of climate change and human factors and is likely to get worse in the future.
175
What are the effects of desertification on people?
- lack of water
- short supply of food – malnutrition
- people are losing their income
- price of food is increasing
- migration
176
Give a fact about population growth in the Sahel
The population of Sahel has risen from 30 million in 1950 to 500 million (1/2 billion) now
177
Why does conflict contribute to desertification in the Sahel?
Refugees are forced into fragile lands where trees are cut down for new houses, firewood and space needed to grow extra food – this puts pressure on land, degrading it further
178
How does over-grazing lead to desertification?
- overgrazing
- so less vegetation to protect the soil from sun
- so the soil is very dry + also there are fewer roots to hold the soil together
- so soil is more easily eroded by wind + rain
- so soil erosion
- so lose fertile topsoil
- so vegetation can't grow
- so desertification
179
What should you say in a conclusion of an answer about the management of desertification strategies?
'there is no silver bullet'
this means there is no one strategy -> often need a few working together
180
What are the 2 overall problems of desertification?
1. Soil erosion -> no fertile topsoil –> so can't grow vegetation
2. Soil baked dry –> water can't infiltrate –> no soil moisture –> can't grow vegetation
181
What are the desertification management strategies?
- afforestation
- stone or soil walls/embankments (bunds)
- appropriate technology (efficient stoves)
182
What is afforestation and what problems does it stop?
It is planting trees
- provides a canopy so soil isn't baked dry
- roots of trees bind soil together which stops soil erosion
- trees absorb CO2 which then reduces climate change
183
How does afforestation stop desertification?
- it stops fertile topsoil from being lost as roots bind the soil
- this shades the ground
- so there is more soil moisture
- so there is more moisture in the atmosphere
- so it rains
- this reduces desertification
- more interception, so increases transpiration, which will increase moisture in atmosphere, so rain increases
184
What is an assessment of afforestation?
- Beneficial strategy as also helps flooding, deforestation + climate change
- Really good strategy as also solves some root causes of desertification
- Reduces climate change
- Creates jobs + wealth
- Not that expensive
- Agroforestry can happen
Example: The great green wall! - across the Sahel
185
What are Bunds (stone or soil walls/embankments) and what problems does it stop?
It is a soil or stone wall/embankment put on farmland so water + topsoil doesn't run away
- traps top soil behind barrier
- barrier stops water so it has time to infiltrate into ground
- vegetation is able to grow on edges of bunds
186
How do bunds stop desertification?
- Traps soil behind the barrier and allows water to infiltrate into ground
- So vegetation can grow
- This reduces desertification
187
What is an assessment of bunds?
- Cheap + affordable
- Easy to maintain
- Naturally gets bigger overtime (because soil is trapped)
- Could be fairly easily damaged
- Can't use heavy machinery
- Likely to only work on subsistence farming – not commercial
- Small scale
188
Who is appropriate technology for?
- the **p**eople
- in terms of **a**ffordability
- the **p**lace
- **s**ustainability
(PAPS)
appropriate technology is 'bottom up' - community driven
189
What are efficient stoves?
Appropriate technology - stoves that require only very small amounts of firewood to work
190
How do efficient stoves stop desertification?
- Less trees cut down so more interception, so more transpiration which increases moisture in atmosphere, so more rain
- less trees cut down so roots of plants hold soil together so less soil ocean
191
What is an assessment of efficient stoves?
- Good strategy
- Good way to heat homes and cook food
- Not planting trees so not fully stopping desertification
