AQA GCSE Geography - The Living World

What does a producer do?

- a producer uses sunlight energy to produce food

What is the nutrient cycle?

1) plants drop leaves => dead material decomposes => nutrients are released into the soil

2) nutrients are then absorbed from the soil by plants => those plants may then be eaten by consumers

3) plant/consumer who ate the plant dies => nutrients returned to the soil

4) transfer of nutrients = nutrient cycling

CASE STUDY 3: Small-Scale Ecosystem

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Location?
What is it?

- Shapton Ley Reed Beds, South Devon
- Shapton Ley is a freshwater lagoon, separated from the sea by a shingle barrier

What 2 organisations protect the lagoon from over-development?

- laggon is a Site of Special Scientific Interest (SSSI)
- lagoon is also a National Nature Reserve (NNR)

What plants/animals do the reed beds provide a habitat for?

- which 2 birds nest in the reed bed and feed on fish?
- which 3 creatures use the reeds for shelter?
- which insect lays its eggs in the water?
- which 2 creatures eat the above creature's larvae?
- what prevents soil erosion?
-what do bearded tits feed off of?
- which 2 consumers feed on the reeds?
- what role do bacteria have in the ecosystem?

- birds like bitterns and herons nest in the reed bed and feed on fish
- sticklebacks, eels and other fish use the reeds for shelter
- dragonflies lay their eggs in the water
- fish and frogs eat the insect larvae
- reed roots bind the soil together, preventing erosion
- birds such as bearded tits feed off reed seedheads
- consumers such as moth larvae and water voles feed on the reeds
- bacteria decompose dead inorganic matter

What is the typical food chain at Slapton Ley?

common reed => moth larva => eel => bittern

What does it mean if the Slapton Ley reed beds are an independent ecosystem?

- all the components depend on each other
- changing one component can have a knock-on effect on other components

What would happen within the Slapton Ley reed beds' ecosystem if a drought dried up the pools?

- insect larvae die => fish and frog populations increase => bittern numbers decline

What would happen within the Slapton Ley reed beds' ecosystem if nutrient-rich runoff from farmland entered the lagoon?

- increased surface algae growth => limits light entering lagoon => waterweed plants in the lagoon die => water beetles have less food (so numbers decline) => fish and ell populations decline

What factor determines the type of ecosystem that forms?

- the climate in an area determines what type of ecosystem forms

What are the features of a tundra ecosystem?

- found at high latitudes (60°N)
- found in Northern Europe, Canada and Alaska
- very cold winters
- brief summers with minimal rainfall

- hardly any trees
- mosses, grasses, and low shrubs

- layer of permanently frozen ground called permafrost

What are the features of a savannah grassland ecosystem?

- found between the tropics
- distinct dry and wet seasons
- relatively low rainfall
- mostly grasses
- a few scattered trees

What are the features of a temperate grassland ecosystem?

- found at higher latitudes (there is more varation in temperature and less rainfall)
- no trees
- only grasses

What are the features of a temperate deciduous forest ecosystem?

- found mainly in the mid-latitiudes where there are four dinstinct seasons
- summers are warm
- winters are relatively mild
- rainfall all year round
- deciduous trees lose their leaves in winter to cope with the colder weather

What are the features of a polar ecosystem?

- found around the north and south poles
- very cold, icy and dry
- no vegetation
- remain dark for several months a year

What are the features of a hot desert ecosystem?

- found between 15° and 35° N/S of the equator
- little rainfall
- very hot during the day
- very cold at night
- shrubs and cacti are sparsely distributed in the sandy soil

What are the features of a tropical rainforest ecosystem?

- found around the equator, between the tropics (hot and wet all year around)
- dense canopies of vegetation forming distinct layers

What are the features of a boreal forest ecosystem?

- aka taiga
- found between 50-60°N
- winters are cold and dry
- summers are mild and moist
- trees are coniferous (evergreen with needles)

What is the climate like in tropical rainforests?

- same all year round
- hot (sun's energy is more intense near the equator as it is overhead all year around)
- very high rainfall

What are the plants like in tropical rainforests?

- most trees are evergreen trees are very tall
- dense vegetation cover
- lots of epiphytes (plants that grow on other living plants and take nutrients and moisture from the air), e.g. orchids and ferns

Why isn't the soil very fertile in tropical rainforests?

- heavy rain washes nutrients away
- only thin layer of surface nutrients due to decayed leaf fall (decay is fast in the warm, moist conditions)

What are the inhabitants like in tropical rainforests?

- many indigenous people have adapted to life in the rainforests
- they hunt, fish, and gather nuts and berries for food
- also grow vegetables in small garden plots

What are the animals like in tropical rainforests?

- many species of animals
- gorillas
- jaguars
- anacondas
- tree frogs
- sloths
- howler monkeys

What is biodiversity?

- the variety of organisms living in a particular area (plants & animals)
- rainforests have an extremely high biodiversity

Why are rainforests stable and productive?

- their climate is always hot and wet

Why is the biodiversity in tropical rainforests decreasing?

- deforestation and uncontrolled development are likely to lead to the extinction of many species → loss of biodiversity

How might the extintion of the agoutis affect a rainforest?

- agoutis can crack open the hard seed pod of the Brazil nut to eat the nut inside
- the agouti can then bury the nuts => these can sprout into new seedlings

- if agoutis become extinct, Brazil nut tree numbers would decline => other animals that depend on the nut tree for food/shelter decline
- people who sell Brazil nuts could also be affected

How do cecropia trees and azteca ants depend on each other?

- azteca ants rely on tree for food food and shelter (tree produces energy-rich food) => without ceropia trees, ants would struggle

- ants fight off other insects that try to feed on the tree
- ants also attack lianas (which compete with the cecropia trees for sunlight) => without azteca ants, cecropia trees would be more vulnerable to predators

What effect can deforestation have on a tropical rainforest?

- cutting down trees => can contribute to climate change

- trees intercept & take up lots of water & release it back into the atmosphere => providing moisture for further rainfall (reducing tree cover may increase the risk of drought, affecting the animals/plants)

- trees stabilise soil with their roots and provide some nutrients when they drop their leaves
- fewer trees => soil would have less protection from heavy rainfall => even fewer nutrients in the soil as they are washed away more easily

To what 3 things are plants adapted to in tropical rainforests?

- high rainfall
- high temperatures
- competition for light

What are the 4 layers of plants with different adaptations?

1) Emergent trees
2) Main canopy
3) Undercanopy
4) Shrub layer

How do trees compete for sunlight?

- trees compete with each other for sunlight by growing tall

How are the leaves of plants adapted for the heavy rainfall?

- thick, wavy leaves with pointed drip-tips => channel rainwater to the point, ecouraging runoff (weight of the water doesn't damage the plant + no standing water for bacteria/fungi to grow)

How are lianas adapted to compete for sunlight?

- lianas use tree trunks to climb up high to reach sunlight

How are trees adapted to the heavy rainfall?

- smooth, thin bark => water runs off easily

What feature do trees have which supports their tall, tree trunks?

- large, stable buttress roots

How are some undercanopy plants adapted to receive the most sunlight?

- large leaves to absorb as much sunlight as possible

How are howler monkeys adapted to keep away from predators?

- howler monkeys have strong limbs so they can move around quickly and easily high up in the canopy

Why do harpy eagles have short, pointed wings?

- so that they can easily manoevre between the dense tangle of trees

How are flying squirrels adapted to escape predators?

- flaps of skin between body and arms that allows them to glide between trees

How are leaf-tailed geckos adapted to escape predators?

- camouflaged to look like leaves so they can hide

Give an example of where an animal in a tropical rainforest has adapted to thee low-light levels on the floor.

- anteaters have a sharp sense of smell so they can detect predators

Why are some rainforest animals nocturnal?

- they feed at night because it's cooler then => save energy

CASE STUDY 5: Deforestation

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Location?
What is it?
How large?

- Amazon Rainforest
- the Amazon is the largest rainsforest on Earth
- covers an area of 8,000,000km²

How many hectares were lost between 2001 and 2012 in the Amazon?

- almost 18m hectares of forest lost

What is the main cause of deforestation in the Amazon Rainforest?

- commercial farming; forest is cleared to make space for cattle grazing or huge plantations (cattle ranching is no. 1 cause, 65-70%)
- space also used to commercially farm soy, as well as, rice, corn and sugar cane

What is the 2nd biggest cause of deforestation in the Amazon?

- subsistence farming (20-25%); forest is cleared by small-scale farmers who need land to grow food for themselves and their families
- many indigenous people are subsistence farmers

What is the 3rd biggest cause of deforestation in the Amazon?

- commercial logging (2-3%); the Amazon is full of valuable hardwood trees such as mahogany
=> logging is extremely tempting for both legal and illegal businesses

What are the other 4 minor causes of deforestation in the Amazon?

- mineral extraction; explosives are sometimes used to clear earth
- energy development; building hydroelectric dams floods large areas of forest
- population growth and migration to the area; poor people are offered land in the rainforest
- road building; areas have tobe cleared for the new roads built for logging

How is climate change an environmental impact of deforestation in the Amazon?

- trees remove CO₂ from the atmosphere
- burning the trees releases carbon dioxide from the fire but also from the carbon dioxide that used to be stored in the trees

How is soil erosion another environmental impact of deforestation in the Amazon?

- less tree canopy to intercept rainfall + fewer tree roots to absorb the water => more water reaches the soil => reduces soil fertility as nutrients in the soil are washed away

=> commercial & subsistence farmers are then forced to find new areas with more fertile soil to farm => further deforestation

What positive economic impacts does the deforestation in the Amazon have?

- economic development, faming in particular, has brought wealth to many Amazonian countries

- the mining industry creates jobs for people

- logging contributes hugely to Brazil's economy

What negative economic impacts does the deforestation in the Amazon have?

- logging can however, also destroy resources that countries depend on, e.g. timber
- logging also reduces the attractiveness of the area to tourists

- local Brazilian rubber tappers (extract natural rubber from rubber trees) have lost their livelihoods as trees have been cut down

In what ways are tropical rainforests valuable to people and the environment?

- many products, including rubber, coffee, chocolate and medicines, are sourced from the rainforest

- sustainable development => long-term benefits (e.g. ecotourism)

- protection => may reduce greenhouse effect by reducing carbon dioxide emissions, and allowing trees to continue absorbing CO₂

- climate change could affect all countries not just where deforestation is actually happening

- rainforests help regulate the climate and water cycle => without them, the risk of drought and flooding in certain areas could increase

What is sustainable development within the rainforest?

- management of the rainforest in a way that we get the resources that we need today, without damaging the environment so that resources aren't available in the future

How can selective logging be used to manage the rainforests sustainably?

- only some trees (e.g. older ones) are felled => most trees remain
=> overall forest structure is kept => allows forest to regenerate (smaller, younger trees can still grow)

How can afforestation be used to manage the rainforest sustainably?

- new trees are planted to replace the ones that are cut down (important that the same type of tree is replanted)

How can ecotourism be used to manage the rainforests sustainably?

- minimises damage & benefits local people

- only a small number of visitors are allowed into an area at a time + rules are imposed to minimise environmental impacts (e.g. waste/litter are disposed of properly)

- ecotourism provides a source of income for the locals => don't have to log/farm to make money => fewer trees are cut down

- can also raise awareness of conservation issues + bring in more money to help protect rainforests

How can education be used to manage the rainforests sustainably?

- educating international community about impacts of deforestation => encourage people to buy products from sustainable sources

- informs local people, who might damage the forest without releasing, of the long-term effects of their actions

- teaching locals about alternative ways to make money that do not damage the rainforest

How can conservation be used to manage rainforests sustainably?

- many countries have set up national parks and nature reserves within rainforests => here, damging activities are restricted

- money can be used to enforce restrictions on damaging activities & promote sustainable use of the rainforests

How can reducing debt be used to manage rainforests sustainably?

- LICs often borrow mone from wealthier countries or organisations (money must be paid back with interest => poorer countries log, farm and mine to make money to pay back the debt

- a reduction in debt means countries don't have to damage the rainforest => rainforests can be conserved

- conservation swap; part of a country's debt is paid off in exchange for a guarantee that the money will be spent on conservation

How can international hardwood agreements be used to manage the rainforests sustainably?

- high demand for hardwood from consumers in rich countries => some tropical hardwood trees are becoming increasingly rare

- international agreements have taken place to try to prevent illegal logging and to promote the use of hardwood from sustainably managed forests
- e.g. the Forest Stewardship Council (FSC) mark sustainably-sourced timber with their logo so that consumers can choose products that do not contribute to unsustainable deforestation

What is the climate like in polar and tundra environments?

- polar areas are very cold, normally below freezing
- tundra areas are not as cold
- precipitation is low
- well defined seasons

What is the soil like in polar and tundra environments?

- ice sheets cover polar areas => no exposed soil
- tundra soil is thin, acidic and not very fertile
- beneath the thin soil is a layer of permafrost (frozen ground), holding trapped greenhouse gases

What are the plants like in polar and tundra environments?

- polar areas have few plants but lichens and mosses can grow on rocks and grasses can grow on the coast

- in tundras, hardy shrubs, grasses, mosses, and lichens are common
- small, short trees may grow in warmer areas

What are the animals like in polar and tundra environments?

- relatively few species in both these environments

- polar bears, penguins, whales and seals are found in polar areas
- lemmings, wolves and reindeer live in tundra areas

What are the people like in polar and tundra environments?

- polar areas are mostly uninhabited (but the Arctic has some indigenous residents & Antarctic has a few scientists who work there)

- tundra areas are home to many indigenous people, as well as oil and gas workers in larger towns

In what ways are cold environments fragile, interdependent ecosystems?

- cold climate causes plants to grow slowly and to decompose slowly when they die => soil is relatively low in nutrients
- herbivores that rely on the slow-growing plants to survive must migrate to areas where plants are able to grow
=> carnivores have to follow the herbivores

In what way can changes to one component of the cold ecosystem have knock-on effects on the whole ecosystem?

- if humans trample on plants, soil is exposed to sunlight & warms up => thaws the permafrost => saturating soil and preventing plant growth
- fewer plants to eat => animals have less food
- melting permafrost also releases greenhouse gases => contribute to global warming

What conditions must plants in tundra environments adapt to?

- adapted to survive the extreme cold and strong winds
- they must also endure the dry winter conditions when all moisture is frozen
- and the wet summer conditions when the ground becomes waterlogged after the top layer of soil thaws

What general adaptations to plants have in cold environments?

- most plants become dormant (inactive) to survive the cold, dark winters
- plants are low-growing and round-shaped to provide protection from the win
- most plants have shallow roots because of the layer of permafrost beneath the soil layer
- leaves are generally small to limit evapotranspiration
- most plats reproduce using underground runners or bulbs to cope with the cold and because the short, warmer, wetter growing season (50-60days)

What general adaptations to animals have in cold environments?

- animals tend to be well-insulated, e.g. thick fur or a layer of blubber, to reduce the amiunt of energy they have to use to keep warm
- some animals hibernate to conserve energy and survive the winter
- many birds migrate south to warmer areas during the winter
- many animals grrow white winter coats for camouflage

What is the issue with biodiversity in cold environments?

- cold environments have a very low biodiversitty as there are fewer species who live here than most other environments
=> this means that when the population of one species changes, it can affect the population of dependent species
- global warming is causing some species to move towards the poles but species already adapted to polar environments cannot go anywhere colder, so are at risk of decline/extinction if climate change causes the polar areas to warm up too much

CASE STUDY 6: Cold Environments

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What are the 4 opportunites for economic development in Alaska?

- energy; most of Alaska's income comes from the oil and gas industry

- mineral resources; materials such as gold, silver, iron ore and copper are all mined in Alaska, particularly in the Tintina gold belt

- fishing; employed around 30,000 fishermen in 2016, of, e.g. salmon, cold and crab

- tourism; tourists are attracted by Alaska's scenic wilderness areas

What are the general challenges to development in Alaska?

- Alaska's population is small
- difficult to access resources and find a workforce due to the extreme conditions, remote location and poor infrastructure

How does the extreme climate of Alaska make development a challenge?

- really cold
- heavy snow
- strong winds
=> exposure to the extreme conditions makes working outside dangerous

How does the inaccessibility of Alaska make development a challenge?

- Alaska is a long way from the res of the US
- some areas are extremely remote
- the mountainous terrain makes access difficult and expensive

- in the winter, the only way to get to some towns is via air travel or via the dangerous icy roads
- in the summer, there are no roads to some towns due to the ground being too soft

- the population of Alaska is small & scattered so people in small towns may be a long way from employent opportunities or services

How do the buildings and infrastructure of Alaska make development a challenge?

- providing buildings and infrastructure to cope with either soft or frozen ground and extreme weather is difficult andd expensive
- most construction can only take place in summer (days are longer and warmer)
- the value of some resources means that people find ways to overcome the challenges

Why is it important that the wilderness areas in cold environments are conserved?

- they provide habitats for organisms that couldn't survive elsewhere
- scientists can study natural environments, including landforms, plants and animals, that are relatively unaffected by people => provides valuable knowledge about fragile ecosystems
- studying natural ecosystens may help scientists to replicate the same conditions in managed => can help to preserve rare species outside the protected areas

Why is it catastrophic is cold environments are damaged?

- cold environments are extremely fragile and can take a long time to recover to their orginal state after human interference because:

- plant growth is slow and if they are damaged, regrowth takes time
- species are highly specialised => diffciult to adapt to further change

How can the role of governments balance economic development with conservation?

- unregulated development can damage the environment
- governments can passlaws, such as the 1964 Wilderness Act, to protect designated wilderness areas from development => development has to take place elsewhere, reducing conflict over land use in wilderness areas

How can international agreements balance economic development with conservation?

- some cold environments are protected by international agreements, e.g. Antarctica
- the 1959 Antarctic Treaty, signed by 12 nations, limits visitors to 100 per site, ensures peaceful non-military activities, porhibits nuclear activities and prevents cruise ships with over 500 passengers from stopping (allows tourism but in a controlled way that won't harm the fragile ecosystem)

How can the use of technology balance economic development with conservation?

- development can cause problems, e.g. heated buildings can melt permafrost, leading to subsidence which may cause buildings to collapse and pipes to crack
- however, modern construction methods can minimise environmental impacts, e.g. by building on gravel beds to prevent buildings warming the ground

How can conservation groups balance economic development with conservation?

- conservation groups, e.g. Greenpeace and the WWF, pressure governments to protect cold environments => can lead to more sustainable development that doesn't damage at-risk areas

Where are the UK's main upland areas?
What rocks are they formed of?

- tend to be in the north and west of the country
- formed of hard, igneous and metamorphic rocks that are resistant to erosion

Where are the UK's main lowland areas?
What rocks are they formed of?

- to the south and east
- formed of softer, sedimentary rocks that erode more easily

Where are most of the UK's major cities?

- most cities are in lowland areas and often on the UK's main rivers
- e.g. London on the Thames, Liverpool on the Mersey, and Cardiff on the Severn Estuary

What is mechanical weathering?

- the breakdown of rock without changing its chemical composition

How does freeze-thaw weathering break down rock?

- happens when the temperature alternates aboe and below 0°C
- water enters rock that has cracks
- when the water freezes, it expands => puts pressure on the rock
- when the water thaws, it contracts => releases pressure on the rock
- repeated freezing and thawing widens the crackss and causes the rock to break up

What is chemical weathering?

- the breakdown of rock by changing its chemical composition

How does carbonation weathering break down rock?

- rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid
- carbonic acid reacts with rock that contains calcium carbonate, so the rocks are dissolved by the limestone

What is mass movement?

- the shifting of rocks and loose material down a slope when the force of gravity acting on a slope is greater than the force supporting it

- causes coasts to retreat rapidly
- more likely to happen when the material is full of water (water acts as a lubricant and makes the material heavier)

What is a scarp?

- a steep cut in the side of a slope after material shifts

What is 'sliding' in mass movement?

- material shifts in a straight line along a slide plane

What is 'slumping' in mass movement?

- material rotates along a curved slip plane

What are 'rockfalls' in mass movement?

- material breaks up, often along bedding planes and falls down a slope

What is the 'fetch' of a wave?

- the distance the wind blows over the sea
- the greater the fetch, the more powerful the wave