Key term
OCR A-Level Geography H481
Coastal Landscapes
Topic overviewThe coastal system: inputs, outputs and flows of energy and materialSediment cells, the sediment budget and the sources of coastal sedimentWinds, fetch and the generation of wavesConstructive and destructive waves, and how waves breakTides, tidal range and ocean currentsLithology, geological structure and the plan of the coastWeathering and mass movement on the coastMarine erosion, transport and depositionBays, headlands, cliffs and shore platformsGeos, blow holes, caves, arches, stacks and stumpsBeaches and the changing beach profileSpits, bars, tombolos and salt marshesHigh and low energy coastlines as characteristic landscapesEmergent coasts: raised beaches, marine terraces and abandoned cliffsSubmergent coasts: rias, fjords and shingle beachesCoastal management and its effect on the sediment budgetPorts, tourism and unintended change at the coast
Glaciated Landscapes
Topic overviewThe glacier system: inputs, stores, flows and outputsGlacier mass balance and the equilibrium lineClimate, latitude and altitude as controls on glaciationGeology, relief and aspect in glaciated landscapesFirn, glacier ice, valley glaciers and ice sheetsWarm-based and cold-based ice, and the mechanisms of glacier movementWeathering, mass movement and nivation in cold environmentsGlacial erosion and the marks it leaves on rockEntrainment, transport and deposition of glacial sedimentCorries, arêtes and pyramidal peaksGlacial troughs, hanging valleys and ribbon lakesMoraines, erratics, drumlins and till sheetsCharacteristic glaciated landscapes and how they change over timeGlacio-fluvial landforms of deglaciation: kames, eskers and outwash plainsPermafrost, patterned ground and pingosPeople in periglacial landscapes: resource extraction and thermokarstPeople in glaciated landscapes: dams, reservoirs and valley change
Dryland Landscapes
Topic overviewDryland landscape systems: inputs, stores, flows and outputsAridity, the water balance and the UNEP aridity indexRainfall, pressure belts and the global pattern of aridityRock type and structure in dryland landscapesRelief, aspect and desert microclimatesSediment supply and the dryland sediment budgetPolar drylands and the cold desertsHot deserts of the low and mid latitudesSemi-arid environments and the desert marginsWeathering and mass movement in dryland landscapesFluvial and aeolian processes in the desertWadis, canyons, pedestal rocks, ventifacts and desert pavementsBarchans, linear dunes, star dunes, alluvial fans and bajadasThe Mojave and the Sahara as desert landscape systemsInselbergs, pediments and relict landforms of past pluvialsFrost-shattered debris, nivation hollows and solifluction depositsWater supply, dams and landscape changeTourism, off-road vehicles and landscape change
Earth’s Life Support Systems
Topic overviewWater and carbon as the foundations of life on EarthOpen and closed systems, and the major global stores of water and carbonInputs and outputs of the water cycle: precipitation, snowmelt and evapotranspirationInputs and outputs of the carbon cycle, and the forms of chemical weatheringEvaporation, transpiration, condensation and the causes of rainfallInterception, runoff and catchment hydrologyPhotosynthesis, respiration, decomposition and combustion as carbon flowsNatural sequestration in oceans, vegetation, sediments and rockStores, flows and physical controls in the tropical rainforestDeforestation, farming and forest management in an Amazon drainage basinStores, flows and seasonal change in the Arctic tundraOil and gas development in the Arctic tundra, and its managementDynamic equilibrium, land use change and water extractionFossil fuel combustion, carbon sequestration and feedback loopsChange over time in the cycles, and the monitoring that records itLinks and interdependence between the water and carbon cyclesGlobal strategies to protect the carbon and water cycles
Changing Spaces; Making Places
Topic overviewThe characteristics that shape a place profileContrasting place profiles: Chelsea and BlackpoolPast and present connections, and the scales that embed a placeShifting flows of people, resources, money and ideasSpace, place and the effects of time-space compressionPerception, identity and emotional attachment to placeInformal representations of place in media and the artsFormal and statistical representations of placeMeasuring social inequality and its spatial patternsDeindustrialisation, globalisation and structural economic changeRecession, austerity and the government's role in inequalityLiving with inequality: Sparkbrook and Sutton ColdfieldPlayers driving economic change at different scalesThe Ruhr: a region reshaped by structural economic changePlacemaking and the marketing of places to investorsDesign, mixed use and community-led placemakingRebranding through reimaging and regenerationSalford Quays: from docks to MediaCityUK
Trade in the Contemporary World
Topic overviewMerchandise, services and capital flowsGlobal trade patterns: inter-regional and intra-regional flowsTrade, export value and human developmentTrade as a driver of growth, stability and developmentTrade inequalities, conflict and injusticeTransport, technology and the global supply chainMultinationals, outsourcing and the new international division of labourRegional trading blocs and the European UnionSouth–south trade and the growth of traded servicesIndia: trade patterns of an emerging economyThe United States: a core economy shaping world tradeEthiopia: trade on the periphery of the global system
Global Migration
Topic overviewThe global migrant population: size, composition and direction of flowInter-regional and intra-regional flows, and the world's major migration corridorsRemittances, the Human Development Index and the migration-development linkMigration as a driver of stability, growth and developmentInequality, conflict and injustice in the global migration systemEconomic globalisation and the emergence of new source and host areasYoung workers, women migrants and the growth of South-South movementConflict, persecution and the world's refugee movementsNational immigration and emigration policy, and how it is changingMexico: an emerging economy shaped by a migration corridorThe United Kingdom: an advanced country driving change in the migration systemNepal: a low-income country with little leverage over its migration
Human Rights
Topic overviewThe idea of human rights and its legal foundationsNorms, intervention and geopoliticsForced labour and modern slaveryMaternal mortality and access to safe childbirthCapital punishment and where it persistsPatterns of gender inequality: schooling, reproductive health and workWomen's rights in IndiaHuman rights abuse as a cause and a consequence of conflictInstitutions, treaties and laws that protect human rightsGlobal governance of human rights in eastern DR CongoShort-term relief and long-term change in DR Congo
Power and Borders
Topic overviewStates, nations and the sovereign control of territoryNorms, intervention and geopoliticsContested borders and the legacy of colonial boundariesTransnational corporations and economic sovereigntyTrading blocs, supranational institutions and pooled sovereigntyEthnic dominance, minority marginalisation and separatismUkraine: sovereignty and territorial integrity under challengeResources, conflict and the causes of geopolitical instabilityGlobal institutions, international law and the flows that carry interventionSouth Sudan: governing a conflict from global to localShort-term and long-term outcomes of intervention for people and placesThe Democratic Republic of the Congo: global governance in an LIDC
Climate Change
Topic overviewReconstructing past climates from natural archivesIcehouse and greenhouse Earth, from Cenozoic cooling to the HoloceneContinental drift and volcanic activity as drivers of climateMilankovitch cycles and changes in solar outputThe natural greenhouse effect and the atmosphere's greenhouse gasesWarming of the surface, atmosphere and oceans since the late 19th centuryRetreating ice, shrinking snow cover and rising sea levelWhy greenhouse gas emissions have risen since the pre-industrial eraThe changing global balance of emissions, from an AC to an EDCThe enhanced greenhouse effect and the global energy balanceThe evolution of the global warming debateGovernments, international organisations and the media in the climate debateClimate models, the carbon cycle and feedbackFuture emission scenarios and projected temperature and sea level riseImpacts on ecosystems, health and extreme weatherThe vulnerability of people and environments to climate changeMitigation through energy efficiency, fuel shifts and low-carbon energyCarbon capture and storage, forestry strategies and geoengineeringRetreat, accommodation and protection as adaptationAdapted homes, cities, transport and economiesContrasting countries: impacts, opportunities and the challenges of respondingThe IPCC, international agreements and policy from global to local
Disease Dilemmas
Topic overviewWays of classifying disease, and the epidemic to pandemic scaleMapping the burden of malaria, HIV, tuberculosis, diabetes and heart diseaseDisease diffusion, the Hägerstrand model and the barriers that slow itTemperature, rainfall, relief and water supply as controls on diseaseMosquitoes, vectors and the seasonal rhythm of outbreaksClimate change, emerging infections and diseases that jump from animalsCholera in Haiti after the 2010 earthquakeRising living standards and the epidemiological transitionDiseases of poverty and diseases of affluenceAir pollution and lung cancer in ChinaMalaria in Nigeria: from causes to controlCardiovascular disease in the United KingdomThe World Health Organization and the surveillance of global outbreaksMédecins Sans Frontières and the West African Ebola epidemicPhysical barriers to treatment and the fight against HIV and AIDSMedicinal plants, their growing conditions and the trade that threatens themPharmaceutical transnationals and the global flow of medicinesEradication campaigns, grassroots education and the role of women
Exploring Oceans
Topic overviewThe size and spread of the world's oceansThe shape of the sea floor, from shelf to trenchSalinity and temperature through the water columnSurface currents and the great ocean gyresThe North Atlantic conveyor, from Gulf Stream to deep return flowLight, warmth and nutrients as limits on ocean lifeFood webs in the inter-tidal zone and the deep seaHarvesting Southern Ocean krillWhaling, stakeholder conflict and resource thresholdsOcean energy: oil, gas, waves and tidesMining the deep sea bed for metalsThe global commons, maritime zones and ocean governanceThe major sources of marine pollutionThe Deepwater Horizon oil spill and its aftermathDrifting plastic and the North Pacific garbage patchOcean acidification, warming seas and coral bleachingRising sea level and low-lying island communitiesSea ice, the albedo feedback and irreversible thresholdsThe changing Arctic: peoples, politics and new sea routesShipping lanes, container ships and seaborne tradeNaval power and contested seasPiracy and migration by sea
Future of Food
Topic overviewFood security and its three pillarsMeasuring hunger: undernourishment data and food security indicesShifting patterns of food security between and within countriesClimate, soil, water and relief as controls on where food can be grownThe journey of food from farm to plate, and the waste it leavesTypes of farming: intensive, extensive, subsistence and commercialGlobalisation, rising demand and global tastesThe issues and opportunities of a globalised food industryLand ownership, competition and land grabbingMalthus, Boserup and the population–resource debateYemen: conflict, aridity and the collapse of food accessVulnerable people and the pinchpoints in global food distributionDesertification and the drylands of the SahelExtreme weather, water scarcity and tectonic shocks to food productionInuit hunting and food security in the ArcticSalinisation, deforestation and agrochemical pollution from farmingThe Aral Sea: a landscape remade by irrigationHealth effects of hunger, over-nutrition and agrochemical exposureMalawi and the United States: contrasting experiences of food insecurityTrade policy, the World Trade Organization and appropriate aidAgribusiness, food TNCs, supermarkets and fair tradeFrom emergency relief to capacity building and system redesign
Hazardous Earth
Topic overviewThe Earth's internal structure and the global pattern of platesContinental drift and the evidence from fossils, rocks and ancient glaciationsSea-floor spreading, palaeomagnetism and the age of the ocean floorDivergent boundaries and the landforms of the mid-ocean ridgesSubduction at oceanic-continental and oceanic-oceanic boundariesContinental collision and conservative boundariesMagma chemistry, viscosity and explosive volcanism at subduction zonesEffusive eruptions, shield volcanoes and hot-spot volcanismVolcano size and shape, super-volcanoes and the Volcanic Explosivity IndexLava flows, pyroclastic flows and volcanic gasesTephra, ashfall, lahars and volcanic tsunamisEarthquake focus, depth and the seismic waves releasedMeasuring earthquakes: Richter, moment magnitude and Mercalli intensityFault scarps, rift valleys and the landscapes faulting createsGround shaking, ground displacement and liquefactionEarthquake-triggered landslides, avalanches and floodingTsunamis from sea-bed uplift and underwater landslidesWhy people choose to live in tectonically active placesThe impacts of volcanic eruptions in countries at contrasting levels of developmentThe impacts of earthquakes in countries at contrasting levels of developmentPredicting, monitoring and managing volcanic hazardsLand-use zoning, building design and managing earthquake riskChanging risk over time and the disaster risk equationThe Park model of disaster response
Geographical Skills
Topic overviewGeographical data, its types and the ethics of using itCollecting data: sampling, measurement error and digital devicesQualitative methods, sources and drawing conclusionsMeasures of central tendency and dispersionCorrelation, lines of best fit and Spearman's rankSignificance tests: chi-squared, Mann-Whitney U and the t-testClimate graphs, maps and graphical techniques
Earth’s Life Support Systems
- 17 subtopics
- 45 things to know
- Component 01
What Earth’s Life Support Systems covers
Earth’s Life Support Systems is examined in Component 01, Physical systems. It covers water and carbon as the foundations of life; open and closed systems and the major global stores of water and carbon; the inputs, outputs and flows that link them, from precipitation, evapotranspiration, interception and runoff to photosynthesis, respiration, decomposition, combustion, chemical weathering and natural sequestration; and how the cycles change over time and are monitored. It also covers the stores, flows and physical controls of the tropical rainforest and the Arctic tundra; deforestation, farming and forest management in the Amazon basin and oil and gas development on the North Slope of Alaska; how land use change, water extraction and fossil fuel combustion disturb dynamic equilibrium and set off feedback loops; the links between the two cycles; and global strategies to protect them.
The 17 subtopics
Each one has its own page.
- Water and carbon as the foundations of life on EarthRecall questions on why water and carbon support life: water as a solvent, its thermal properties and role in photosynthesis and transpiration, human water use by sector, wetlands, carbon chemistry and the biosphere, human use of carbon resources, the fast and slow carbon cycles, and carbon dioxide as a resource.Open →
- Open and closed systems, and the major global stores of water and carbonRecall questions on open and closed systems, stores and flows, how water and carbon move between ocean, atmosphere and land, the sizes of the ocean, cryosphere, groundwater, lake and atmospheric water stores, a residence time calculation, and the rock, ocean, atmosphere, soil and vegetation carbon stores.Open →
- Inputs and outputs of the water cycle: precipitation, snowmelt and evapotranspirationRecall questions on drainage basin inputs and outputs, potential and actual evapotranspiration, ablation and snowmelt regimes, the conditions and vegetation that raise evapotranspiration, the water balance equation with worked runoff and volume calculations, and summer soil moisture deficits.Open →
- Inputs and outputs of the carbon cycle, and the forms of chemical weatheringRecall questions on how precipitation, photosynthesis, decomposition, plant and soil respiration and combustion move carbon, the photosynthesis equation, carbonation, hydrolysis and oxidation weathering, and the carbon moved each year by weathering and by burning fossil fuels.Open →
- Evaporation, transpiration, condensation and the causes of rainfallRecall questions on evaporation and its controls, stomata and transpiration, condensation, dew point and condensation nuclei, the dry and saturated adiabatic lapse rates with a worked calculation, convectional, frontal and orographic rainfall, rain shadows, and how cloud droplets grow into rain.Open →
- Interception, runoff and catchment hydrologyRecall questions on interception, infiltration and infiltration capacity, infiltration-excess and saturated overland flow, percolation, throughflow and groundwater flow, porosity, permeability and the chalk aquifer, cryospheric processes, a discharge calculation, and fieldwork on infiltration and interception.Open →
- Photosynthesis, respiration, decomposition and combustion as carbon flowsRecall questions on gross and net primary productivity, productivity in rainforest and tundra, the respiration equation, soil respiration and the decomposition of a leaf, methane from waterlogged ground, wildfire and fossil fuel combustion, and the residence time of atmospheric carbon.Open →
- Natural sequestration in oceans, vegetation, sediments and rockRecall questions on carbon sequestration, the solubility, biological and carbonate pumps, the formation of limestone, net carbon uptake by the oceans and land biosphere, soil carbon, carbon in sedimentary rock and silicate weathering, and blue carbon.Open →
- Stores, flows and physical controls in the tropical rainforestRecall questions on the rainfall and temperature of the Amazon rainforest, its fast water cycle, interception and recycled rainfall, where its carbon is stored, rapid decomposition and latosols, and how temperature, rock permeability, relief and mineral composition control both cycles.Open →
- Deforestation, farming and forest management in an Amazon drainage basinRecall questions on the causes and scale of Amazon deforestation, its effects on runoff, storm hydrographs, rainfall, soils and carbon, afforestation, agroforestry, selective logging and REDD+, the tipping point, the Amazon flood pulse, droughts and El Niño, record levels of the Rio Negro at Manaus, and comparing soil organic matter.Open →
- Stores, flows and seasonal change in the Arctic tundraRecall questions on the precipitation and temperatures of the Arctic tundra, permafrost and the active layer, its slow water cycle, the permafrost carbon store and tundra vegetation, the short growing season, spring melt and seasonal carbon exchange, and the effects of bedrock, relief and albedo.Open →
- Oil and gas development in the Arctic tundra, and its managementRecall questions on the Prudhoe Bay field and the Trans-Alaska Pipeline, how construction thaws permafrost, and the measures used to limit the damage.Open →
- Dynamic equilibrium, land use change and water extractionRecall questions on dynamic equilibrium in the cycles, how urban growth, ploughing, commercial forestry and peatland drainage change water and carbon stores, aquifers, confined and unconfined, the Great Artesian Basin, over-abstraction and the Ogallala aquifer, and the effects of surface extraction and reservoirs.Open →
- Fossil fuel combustion, carbon sequestration and feedback loopsRecall questions on the rise in atmospheric carbon dioxide since the industrial era, how much human carbon stays airborne, carbon capture and storage at Sleipner and its limits, the permafrost carbon, ice-albedo and water vapour feedbacks, negative feedbacks, and why methane matters.Open →
- Change over time in the cycles, and the monitoring that records itRecall questions on daily and seasonal change in the cycles, the sawtooth carbon dioxide record, deciduous woodland and monsoon water cycles, long-term change through volcanic outgassing, the carbonate-silicate cycle, the Carboniferous and glacial periods, and monitoring by Mauna Loa, ice cores, flux towers and satellites.Open →
- Links and interdependence between the water and carbon cyclesRecall questions on how the oceans, cryosphere, atmosphere and a single leaf link the two cycles, ocean acidification, plant water use under higher carbon dioxide, human use of carbon stores, a more intense water cycle as the climate warms, glacier-fed rivers, drought turning forest into a carbon source, and sea-level rise.Open →
- Global strategies to protect the carbon and water cyclesRecall questions on afforestation and China's Three-North Shelterbelt, peatland restoration, soil carbon farming and agroforestry, carbon trading and the EU Emissions Trading System, the Paris Agreement and the Kyoto Protocol, improved forestry, integrated drainage basin management, water allocation, and shared river basins.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why does a wetland support a high density of animal life?
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What role do stomata play in transpiration?
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Why does burning fossil fuel differ in effect from burning a forest that then regrows?
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Name two agricultural techniques that reduce the damage farming does to the cycles.
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How does selective logging differ from clear felling in its effect on the water cycle?
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How does the carbonate-silicate cycle regulate climate over millions of years?
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How are the two cycles linked at the scale of a single leaf?
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What is an open system?
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What is an input in a drainage basin system?
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State the balanced chemical equation for photosynthesis.
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What is interception?
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What is carbon sequestration?
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State the typical annual rainfall of the Amazon rainforest.
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Describe the precipitation regime of the Arctic tundra.
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Name the largest oil field in North America and the region in which it lies.
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What is dynamic equilibrium in the water and carbon cycles?
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What fraction of the carbon released by human activity stays in the atmosphere?
Numbers
Name a large national afforestation programme and the problem it addresses.
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How does carbon move between the land, the oceans and the atmosphere?
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Name three outputs of a drainage basin system.
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What is decomposition in the carbon cycle?
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What is evaporation?
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What is infiltration?
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What is gross primary productivity?
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Why does warm tropical seawater hold less dissolved carbon dioxide than cold polar water?
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Describe the temperature regime of a tropical rainforest.
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State the typical summer and winter temperatures of the Arctic tundra.
Numbers
When did oil production begin on Alaska's North Slope?
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What happens to a store when its inputs exceed its outputs?
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What is carbon capture and storage?
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Why does transpiration peak in the early afternoon?
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How do the oceans link the water and carbon cycles?
Evaluation
Give two limitations of afforestation as a climate strategy.
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How is water used in photosynthesis?
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What is a store in a systems context?
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What is meant by evapotranspiration?
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Which conditions make decomposition fastest?
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State three factors that control the rate of evaporation from an open water surface.
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What is infiltration capacity?
Key term
Compare net primary productivity in a tropical rainforest with that of tundra.
Process
How does limestone form from marine organisms?
Key term
Why is the water cycle of a tropical rainforest described as fast?
Numbers
State the approximate proportion of the Amazon rainforest that has already been cleared.
Key term
What is permafrost, which underlies the Arctic tundra?
Take Earth’s Life Support Systems further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Open system vs Closed system
Open system: one whose boundary both energy and matter can cross, as a drainage basin does when it gains rain and loses water to the sea. Closed system: one whose boundary energy can cross but matter cannot, as the water cycle does at the global scale.
Porosity vs Permeability
Porosity: the proportion of a rock made up of pore spaces that can hold water. Permeability: the ease with which water can pass through a rock, which depends on whether its pores are joined up.
Infiltration-excess overland flow vs Saturated overland flow
Infiltration-excess overland flow: water runs across the ground because rain is arriving faster than the soil can take it in, even though the soil is not yet full. Saturated overland flow: water runs across the ground because the pore spaces are already full, so any further rain has nowhere to go but the surface.
Questions from this topic
Each one with the model answer underneath.
- 1
Why is liquid water described as the universal solvent of life?
Model answer
It dissolves nutrients, gases and salts, allowing them to be transported around an organism and to react inside its cells.
- 2
State two properties of water that allow it to moderate temperature.
Model answer
Water has a high specific heat capacity, so it warms and cools slowly, and a high latent heat of vaporisation, so evaporation removes large amounts of heat from a surface.
- 3
How is water used in photosynthesis?
Model answer
Water supplies the hydrogen that is combined with carbon dioxide to build glucose, and the oxygen released as a by-product comes from the water molecule.
- 4
How does transpiration help a plant obtain mineral nutrients?
Model answer
Water lost from the leaves pulls a continuous column of water up the xylem from the roots, and dissolved minerals are carried up with it.
- 5
Name the three sectors of human water use in order of the volume they withdraw.
Model answer
Agriculture is much the largest at roughly 70% of withdrawals, then industry at about 20%, then domestic use for drinking, cooking, washing and sanitation at around 10%.
- 6
Why does a wetland support a high density of animal life?
Model answer
Permanent shallow water provides drinking water, aquatic plants and invertebrates as food, and sheltered breeding habitat, so many species can be supported in a small area.
What is inside Levo
Six ways to work the same material.
Earth’s Life Support Systems revision questions
- What does Earth’s Life Support Systems cover in OCR A-Level Geography?
- 17 subtopics: water and carbon as the foundations of life on earth, open and closed systems, and the major global stores of water and carbon, inputs and outputs of the water cycle: precipitation, snowmelt and evapotranspiration, inputs and outputs of the carbon cycle, and the forms of chemical weathering, evaporation, transpiration, condensation and the causes of rainfall, interception, runoff and catchment hydrology, photosynthesis, respiration, decomposition and combustion as carbon flows, natural sequestration in oceans, vegetation, sediments and rock, stores, flows and physical controls in the tropical rainforest, deforestation, farming and forest management in an amazon drainage basin, stores, flows and seasonal change in the arctic tundra, oil and gas development in the arctic tundra, and its management, dynamic equilibrium, land use change and water extraction, fossil fuel combustion, carbon sequestration and feedback loops, change over time in the cycles, and the monitoring that records it, links and interdependence between the water and carbon cycles and global strategies to protect the carbon and water cycles. Each one has its own page with questions and model answers.
- How is Earth’s Life Support Systems organised?
- By the OCR H481 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Earth’s Life Support Systems, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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