Easy — Foundations

• 1Environmental value systemsDefine a worldview that shapes how a person perceives environmental issues.Why it mattersThe core organising concept of the whole ESS course.Easy
• 2Inputs and outputs of an EVSIdentify the information that shapes values and the decisions that result.Why it mattersTreats a worldview itself as a system to be analysed.Easy
• 3EcocentrismDescribe a nature-centred worldview prioritising ecological integrity.Why it mattersOne of the three worldviews examiners expect you to name.Easy
• 4AnthropocentrismDescribe a people-centred worldview emphasising resource management.Why it mattersThe worldview behind most environmental regulation.Easy
• 5TechnocentrismDescribe a worldview trusting technology to solve environmental problems.Why it mattersThe worldview behind geoengineering proposals.Easy
• 6Factors shaping environmental viewpointsIdentify culture, religion, education, media and economic context.Why it mattersExplains why people disagree about identical evidence.Easy

Medium — Applications

• 7Comparing the three worldviewsExplain differing attitudes to growth, technology and nature.Why it mattersA guaranteed comparison question in Paper 1.Medium
• 8The spectrum of environmental viewpointsExplain positions ranging from deep ecologist to cornucopian.Why it mattersShows worldviews vary in degree, not only in kind.Medium
• 9Historical development of the environmental movementExplain key events that shaped public environmental awareness.Why it mattersProvides the named examples every essay needs.Medium
• 10Influential publications and campaignsExplain how books and media shifted public opinion.Why it mattersExplains sudden changes in environmental policy.Medium
• 11International conferences and agreementsExplain the role of major global environmental summits.Why it mattersMarks the milestones of environmental governance.Medium
• 12Personal and societal valuesExplain the difference between individual and collective positions.Why it mattersExplains conflict between citizens and their governments.Medium

Hard — Structured IB

• 13Analysing how an EVS shapes decision-makingExamine how identical evidence produces different responses.Why it mattersThe applied significance of worldview analysis.Hard
• 14Analysing the influence of media on valuesExamine framing, coverage and selective reporting.Why it mattersExplains shifts in public concern over time.Hard
• 15Analysing economic influences on viewpointsExamine how wealth and livelihood shape environmental priorities.Why it mattersExplains differences between and within countries.Hard
• 16Analysing cultural and religious influencesExamine beliefs about humanity's relationship with nature.Why it mattersExplains persistent international policy disagreement.Hard
• 17Analysing the role of environmental disastersExamine how crises accelerate changes in public opinion.Why it mattersExplains policy change following major incidents.Hard
• 18Analysing the limitations of EVS classificationExamine the difficulty of placing real people in fixed categories.Why it mattersPrevents oversimplified labelling of individuals.Hard

Very Hard — Integrated SL

• 19Evaluating a named environmental issue from three worldviewsJudge how each perspective would respond to the same problem.Why it mattersThe classic Paper 2 extended-response structure.Very Hard
• 20Assessing your own environmental value systemJustify a position using explicit criteria and evidence.Why it mattersA frequent reflective question in Paper 1.Very Hard
• 21Evaluating the influence of a historical eventJudge its lasting effect on environmental attitudes.Why it mattersRewards use of specific named examples.Very Hard
• 22Judging which worldview best addresses a problemEvaluate practicality against ethical consistency.Why it mattersRequires prioritisation rather than description.Very Hard
• 23Integrating EVS analysis with sustainability decisionsLink worldview to the choice of management strategy.Why it mattersRewards synoptic reasoning across the whole course.Very Hard
• 24Constructing a full EVS-based evaluationBuild a structured argument with a clear supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Systems thinkingDefine analysing components and their interactions as a whole.Why it mattersThe organising framework for all of ESS.Easy
• 2Storages and flowsDistinguish where matter or energy is held from how it moves.Why it mattersThe vocabulary required for every systems diagram.Easy
• 3Open systemsDefine systems exchanging both matter and energy with their surroundings.Why it mattersDescribes almost every natural ecosystem.Easy
• 4Closed systemsDefine systems exchanging energy but not matter.Why it mattersDescribes the Earth system taken as a whole.Easy
• 5Isolated systemsDefine systems exchanging neither matter nor energy.Why it mattersA theoretical case used mainly for comparison.Easy
• 6Systems diagramsConstruct a diagram with labelled storages and flows.Why it mattersA guaranteed diagram skill in Paper 1.Easy

Medium — Applications

• 7Steady-state equilibriumExplain a system fluctuating around a stable long-term average.Why it mattersDescribes a healthy functioning ecosystem.Medium
• 8Static and dynamic equilibriumDistinguish an unchanging system from one in continuous change.Why it mattersPrecise terminology here is tested directly.Medium
• 9Negative feedbackExplain a loop that counteracts change and restores stability.Why it mattersThe mechanism maintaining ecosystem balance.Medium
• 10Positive feedbackExplain a loop that amplifies change and destabilises a system.Why it mattersExplains runaway effects such as ice-albedo feedback.Medium
• 11Tipping pointsExplain thresholds beyond which change becomes self-sustaining.Why it mattersExplains abrupt and often irreversible ecosystem shifts.Medium
• 12ResilienceExplain a system's ability to absorb disturbance and recover.Why it mattersDetermines how much pressure a system can withstand.Medium

Hard — Structured IB

• 13The first law of thermodynamicsAnalyse the conservation of energy within a system.Why it mattersUnderlies all energy flow calculations in ESS.Hard
• 14The second law of thermodynamicsAnalyse the increase in entropy during energy transfer.Why it mattersExplains why energy is lost at each trophic level.Hard
• 15Analysing feedback in a named systemExamine one specific loop with its cause and its effect.Why it mattersTurns a definition into applied analysis.Hard
• 16Analysing factors affecting resilienceExamine diversity, system size and speed of reproduction.Why it mattersDetermines vulnerability to future disturbance.Hard
• 17Analysing the use of modelsExamine simplification, prediction and inevitable inaccuracy.Why it mattersEvery ESS model must be evaluated in this way.Hard
• 18Analysing transfers and transformationsDistinguish change of location from change of form.Why it mattersA distinction examiners test directly.Hard

Very Hard — Integrated SL

• 19Evaluating the usefulness of a modelJudge predictive value against simplifying assumptions.Why it mattersA guaranteed evaluation question in Paper 1.Very Hard
• 20Assessing the resilience of a named ecosystemJudge recovery capacity using specific evidence.Why it mattersApplies theory to a concrete example.Very Hard
• 21Evaluating the significance of tipping pointsJudge their implications for environmental management.Why it mattersExplains the case for precautionary policy.Very Hard
• 22Judging whether a system is sustainableEvaluate inputs and outputs against long-term viability.Why it mattersConnects systems analysis directly to sustainability.Very Hard
• 23Integrating systems analysis with management strategiesLink feedback understanding to intervention choices.Why it mattersRewards synoptic reasoning across the course.Very Hard
• 24Constructing a full systems-based evaluationBuild a diagram-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1SustainabilityDefine use of resources at a rate allowing natural replacement.Why it mattersThe central concept of the entire course.Easy
• 2Sustainable developmentDefine development meeting present needs without compromising the future.Why it mattersThe policy application of sustainability.Easy
• 3Natural capitalDefine natural resources that produce a sustainable flow of goods.Why it mattersThe economic framing of environmental resources.Easy
• 4Natural incomeDefine the sustainable yield obtained from natural capital.Why it mattersDetermines the safe rate of resource use.Easy
• 5Ecological footprintDefine the land area needed to support a population's consumption.Why it mattersThe most widely used sustainability indicator.Easy
• 6Environmental justiceDefine fair distribution of environmental benefits and burdens.Why it mattersExplains why pollution burdens fall unequally.Easy

Medium — Applications

• 7Sustainability indicatorsExplain biodiversity, pollution and resource-use measures.Why it mattersEnables sustainability to be measured rather than asserted.Medium
• 8Calculating and interpreting ecological footprintExplain what a footprint exceeding biocapacity implies.Why it mattersShows whether consumption is genuinely sustainable.Medium
• 9The Sustainable Development GoalsExplain the internationally agreed global development targets.Why it mattersThe framework for measuring worldwide progress.Medium
• 10Citizen scienceExplain public participation in environmental data collection.Why it mattersExpands monitoring coverage at very low cost.Medium
• 11Planetary boundariesExplain safe operating limits for key Earth systems.Why it mattersIdentifies which limits have already been exceeded.Medium
• 12The circular economyExplain designing out waste through reuse and recycling.Why it mattersThe main alternative to linear resource use.Medium

Hard — Structured IB

• 13Analysing the limitations of ecological footprintExamine data assumptions and simplification.Why it mattersPrevents overconfident use of a single figure.Hard
• 14Analysing conflicts within sustainable developmentExamine tension between growth and environmental limits.Why it mattersThe central tension in every development question.Hard
• 15Analysing doughnut economicsExamine the space between social floor and ecological ceiling.Why it mattersAn alternative economic framing in the syllabus.Hard
• 16Analysing environmental justice case evidenceExamine unequal exposure to pollution and environmental risk.Why it mattersConnects sustainability directly to equity.Hard
• 17Analysing the reliability of citizen science dataExamine training, consistency and verification.Why it mattersDetermines the weight such data can carry.Hard
• 18Analysing sustainability frameworksExamine how different frameworks define success.Why it mattersExplains conflicting assessments of the same policy.Hard

Very Hard — Integrated SL

• 19Evaluating a named sustainability indicatorJudge usefulness against measurement problems.Why it mattersA standard Paper 1 evaluation question.Very Hard
• 20Assessing whether growth and sustainability are compatibleWeigh economic development against ecological limits.Why it mattersA guaranteed extended-response debate.Very Hard
• 21Evaluating the Sustainable Development GoalsJudge coordination value against measurement difficulty.Why it mattersTests critical assessment of an institution.Very Hard
• 22Judging responsibility for sustainable developmentEvaluate obligations of richer and poorer countries.Why it mattersRaises a contested global equity issue.Very Hard
• 23Integrating sustainability with EVS and systems thinkingBuild one argument linking all three chapter concepts.Why it mattersThe synoptic reasoning examiners reward.Very Hard
• 24Constructing a full sustainability evaluationBuild a structured argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Levels of ecological organisationIdentify individual, population, community, ecosystem and biome.Why it mattersThe hierarchy underlying all ecological analysis.Easy
• 2Species, habitat and nicheDistinguish the organism, where it lives and the role it occupies.Why it mattersPrecise terminology here is tested directly.Easy
• 3Abiotic and biotic factorsDistinguish non-living from living influences on organisms.Why it mattersThe two categories of limiting factor.Easy
• 4Classification and taxonomyDescribe the hierarchical grouping of organisms.Why it mattersEnables consistent identification during fieldwork.Easy
• 5Dichotomous keysDescribe the use of paired questions to identify species.Why it mattersA required practical skill in ESS.Easy
• 6PopulationDefine a group of organisms of one species in one area.Why it mattersThe basic unit of all population study.Easy

Medium — Applications

• 7Factors affecting population sizeExplain natality, mortality, immigration and emigration.Why it mattersThe four variables determining population change.Medium
• 8Carrying capacityExplain the maximum population an environment can sustain.Why it mattersDetermines the limit to any population's growth.Medium
• 9Exponential and logistic growthCompare unlimited growth with growth approaching a limit.Why it mattersThe two curves you must be able to draw.Medium
• 10Limiting factorsExplain resources and conditions that constrain population growth.Why it mattersExplains why populations eventually level off.Medium
• 11Species interactionsExplain predation, competition, parasitism and mutualism.Why it mattersThe biotic influences shaping population size.Medium
• 12Human population patternsExplain global trends in population size and distribution.Why it mattersLinks ecology directly forward to Chapter 8.Medium

Hard — Structured IB

• 13Quadrat samplingAnalyse the estimation of abundance within a defined area.Why it mattersA required practical technique in ESS.Hard
• 14Transect methodsAnalyse the recording of distribution along an environmental gradient.Why it mattersUsed to investigate zonation in the field.Hard
• 15Capture-mark-recaptureAnalyse the estimation of mobile animal population size.Why it mattersThe standard method for motile species.Hard
• 16Analysing sampling error and biasExamine sample size, placement and researcher effects.Why it mattersDetermines confidence in any field estimate.Hard
• 17Analysing r and K reproductive strategiesExamine trade-offs between offspring number and parental care.Why it mattersExplains differing responses to disturbance.Hard
• 18Analysing ecosystem functioning and sustainabilityExamine how interactions maintain long-term stability.Why it mattersConnects population ecology to ecosystem health.Hard

Very Hard — Integrated SL

• 19Evaluating a named population sampling methodJudge accuracy against practicality and ethics.Why it mattersA guaranteed practical evaluation question.Very Hard
• 20Assessing the reliability of population dataJudge method, sample size and repeat measurement.Why it mattersRequired whenever field data is presented.Very Hard
• 21Evaluating the concept of carrying capacity for humansJudge its applicability given technology and trade.Why it mattersA contested and frequently examined issue.Very Hard
• 22Judging the sustainability of a named ecosystemEvaluate evidence of stability against human pressure.Why it mattersApplies theory to one specific case.Very Hard
• 23Integrating population ecology with resource managementLink population dynamics to harvesting decisions.Why it mattersRewards a synoptic link forward into Chapter 4.Very Hard
• 24Constructing a full ecological evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Producers and consumersDistinguish organisms making their own food from those consuming others.Why it mattersThe basis of every trophic diagram.Easy
• 2PhotosynthesisDescribe the conversion of light energy into chemical energy.Why it mattersThe entry point of energy into all ecosystems.Easy
• 3RespirationDescribe the release of energy from organic molecules.Why it mattersExplains energy loss at every trophic level.Easy
• 4Trophic levelsDefine the feeding position an organism occupies.Why it mattersThe organising concept of energy flow.Easy
• 5Food chains and food websDistinguish a single pathway from an interconnected network.Why it mattersFood webs represent real ecosystem complexity.Easy
• 6BiomassDefine the total mass of living organic material.Why it mattersThe measurable stock of energy at a trophic level.Easy

Medium — Applications

• 7Energy losses between trophic levelsExplain respiration, excretion and incomplete consumption.Why it mattersExplains why food chains are always short.Medium
• 8Ecological efficiencyExplain the proportion of energy passed to the next level.Why it mattersThe basis of all energy transfer calculations.Medium
• 9Gross and net primary productivityDistinguish total energy fixed from energy remaining after respiration.Why it mattersTwo terms students very frequently confuse.Medium
• 10Gross and net secondary productivityDistinguish consumer energy assimilated from that remaining.Why it mattersCompletes the productivity terminology.Medium
• 11Pyramids of numbers, biomass and productivityCompare the three forms of ecological pyramid.Why it mattersEach reveals different ecosystem information.Medium
• 12Constructing ecological pyramidsDraw pyramids accurately to scale from given data.Why it mattersA guaranteed practical diagram skill.Medium

Hard — Structured IB

• 13Calculating productivityApply the relationships between gross, net and respiration.Why it mattersA guaranteed quantitative task in ESS.Hard
• 14Calculating energy transfer efficiencyCompute the percentage passed between trophic levels.Why it mattersA standard Paper 2 calculation.Hard
• 15Analysing anomalies in pyramid shapeExamine inverted pyramids and their causes.Why it mattersExplains why numbers pyramids can mislead.Hard
• 16Analysing bioaccumulation and biomagnificationExamine toxin concentration up the food chain.Why it mattersExplains harm to top predators from diffuse pollution.Hard
• 17Analysing human impacts on energy flowExamine harvesting, agriculture and habitat change.Why it mattersConnects ecology to human resource use.Hard
• 18Analysing the implications of energy loss for dietExamine efficiency of plant against animal food production.Why it mattersA frequent applied evaluation in food systems.Hard

Very Hard — Integrated SL

• 19Evaluating the usefulness of ecological pyramidsJudge clarity against measurement difficulty.Why it mattersA guaranteed Paper 1 evaluation.Very Hard
• 20Assessing the sustainability of a named food production systemJudge efficiency and environmental cost together.Why it mattersRewards applied use of energy flow theory.Very Hard
• 21Evaluating measures of productivityJudge accuracy against practical measurement problems.Why it mattersDetermines confidence in reported ecosystem data.Very Hard
• 22Judging the case for reduced meat consumptionEvaluate efficiency arguments against social factors.Why it mattersApplies energy flow to a contemporary debate.Very Hard
• 23Integrating energy flow with nutrient cyclingBuild one combined account of ecosystem functioning.Why it mattersRewards a synoptic link forward into Unit 2.3.Very Hard
• 24Constructing a full energy flow evaluationBuild a diagram-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Biogeochemical cyclesDefine the circulation of elements through living and non-living stores.Why it mattersExplains how matter is recycled while energy flows through.Easy
• 2Storages and flows of matterDistinguish where nutrients are held from how they move.Why it mattersThe systems vocabulary applied to nutrients.Easy
• 3The carbon cycleDescribe the main storages and flows of carbon.Why it mattersThe cycle most disrupted by human activity.Easy
• 4Carbon storagesIdentify atmosphere, oceans, biomass, soil and fossil fuels.Why it mattersRequired detail for any carbon cycle diagram.Easy
• 5Carbon flowsIdentify photosynthesis, respiration, decomposition and combustion.Why it mattersThe processes moving carbon between storages.Easy
• 6DecompositionDescribe the breakdown of organic matter releasing nutrients.Why it mattersReturns nutrients to the soil for reuse.Easy

Medium — Applications

• 7Drawing a carbon cycle diagramConstruct a labelled systems diagram of carbon.Why it mattersA guaranteed Paper 1 diagram.Medium
• 8The role of oceans in carbon cyclingExplain dissolution and biological carbon uptake.Why it mattersThe largest active carbon sink on Earth.Medium
• 9Carbon sinks and sourcesDistinguish net absorbers from net emitters of carbon.Why it mattersDetermines whether a system helps or worsens warming.Medium
• 10Human disruption of the carbon cycleExplain combustion, deforestation and land use change.Why it mattersThe direct cause of rising atmospheric carbon.Medium
• 11The nitrogen cycleExplain fixation, nitrification and denitrification.Why it mattersA second major cycle disrupted by agriculture.Medium
• 12Human disruption of the nitrogen cycleExplain fertiliser use and its downstream consequences.Why it mattersLinks nutrient cycling directly to eutrophication.Medium

Hard — Structured IB

• 13Analysing residence time in storagesExamine how long carbon remains in each store.Why it mattersDetermines the persistence of emitted carbon.Hard
• 14Analysing the effect of deforestation on cyclingExamine loss of both storage and uptake capacity.Why it mattersA double impact frequently overlooked in answers.Hard
• 15Analysing feedback in the carbon cycleExamine permafrost thaw and ocean warming loops.Why it mattersExplains acceleration of climate change.Hard
• 16Analysing strategies to reduce carbon impactsExamine reforestation, capture and reduced combustion.Why it mattersThe applied policy content of this topic.Hard
• 17Analysing soil as a carbon storeExamine agricultural practices affecting soil carbon.Why it mattersLinks carbon cycling directly to Chapter 5.Hard
• 18Analysing data on atmospheric carbonInterpret trends in measured concentration data.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating strategies to reduce carbon emissionsJudge effectiveness, cost and feasibility together.Why it mattersA guaranteed extended-response question.Very Hard
• 20Assessing reforestation as a carbon solutionJudge sequestration potential against land competition.Why it mattersRequires balanced two-sided reasoning.Very Hard
• 21Evaluating carbon capture technologyJudge technical promise against cost and scale.Why it mattersA technocentric solution requiring critical assessment.Very Hard
• 22Judging responsibility for carbon cycle disruptionEvaluate historic emissions against current emissions.Why it mattersRaises a contested global equity question.Very Hard
• 23Integrating carbon cycling with climate change policyLink cycle disruption to mitigation strategy.Why it mattersRewards a synoptic link forward into Chapter 6.Very Hard
• 24Constructing a full nutrient cycling evaluationBuild a diagram-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Weather and climateDistinguish short-term conditions from long-term averages.Why it mattersA distinction examiners test directly.Easy
• 2BiomesDefine large regions sharing climate, soil and characteristic organisms.Why it mattersThe organising unit of global ecology.Easy
• 3Major biome typesIdentify forest, grassland, desert and tundra biomes.Why it mattersThe named examples required in written answers.Easy
• 4InsolationDefine incoming solar radiation received at the surface.Why it mattersThe primary driver of all climate patterns.Easy
• 5Latitude and insolationDescribe how the curvature of Earth varies energy received.Why it mattersExplains the global pattern of temperature.Easy
• 6ClimographsInterpret graphs of temperature and precipitation together.Why it mattersA required data skill in ESS.Easy

Medium — Applications

• 7Tricellular atmospheric circulationExplain the Hadley, Ferrel and Polar cells.Why it mattersExplains the global distribution of rainfall.Medium
• 8Distribution of biomesExplain why biomes occur at characteristic latitudes.Why it mattersLinks circulation directly to vegetation patterns.Medium
• 9Ocean currentsExplain surface and deep currents redistributing heat.Why it mattersModerates climate far from the equator.Medium
• 10The thermohaline circulationExplain density-driven global ocean circulation.Why it mattersA system with potential tipping point behaviour.Medium
• 11Characteristics of tropical rainforestExplain its climate, productivity and biodiversity.Why it mattersThe highest productivity terrestrial biome.Medium
• 12Characteristics of desert and tundraExplain limiting factors and low productivity.Why it mattersContrasting cases used in comparison questions.Medium

Hard — Structured IB

• 13Analysing biome productivity differencesExamine temperature, water and light as limiting factors.Why it mattersExplains variation in global productivity.Hard
• 14Analysing the effect of ocean currents on climateExamine specific named current systems.Why it mattersExplains regional climate anomalies.Hard
• 15Analysing climate change effects on biome distributionExamine shifting ranges and moving boundaries.Why it mattersConnects biome study forward to Chapter 6.Hard
• 16Interpreting climate dataAnalyse climographs to identify the biome type.Why it mattersA guaranteed Paper 2 data task.Hard
• 17Analysing the role of albedoExamine surface reflectivity and energy absorption.Why it mattersExplains ice-albedo feedback in polar regions.Hard
• 18Analysing human modification of biomesExamine conversion for agriculture and settlement.Why it mattersExplains the loss of natural biome extent.Hard

Very Hard — Integrated SL

• 19Evaluating the biome conceptJudge its usefulness against boundary imprecision.Why it mattersPrevents uncritical use of a simplifying model.Very Hard
• 20Assessing vulnerability of a named biomeJudge threats using climate and human pressure evidence.Why it mattersRewards applied use of a specific example.Very Hard
• 21Evaluating predictions of biome shiftJudge model reliability against acknowledged uncertainty.Why it mattersConnects biomes to climate model evaluation.Very Hard
• 22Judging the significance of ocean circulation changeEvaluate consequences of thermohaline disruption.Why it mattersA tipping point with major regional impact.Very Hard
• 23Integrating climate patterns with biodiversity distributionLink climate drivers to global species richness.Why it mattersRewards a synoptic link forward into Chapter 3.Very Hard
• 24Constructing a full climate and biome evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1SuccessionDefine directional change in community composition over time.Why it mattersThe core concept of ecosystem development.Easy
• 2Primary successionDescribe colonisation of newly exposed bare substrate.Why it mattersOccurs after volcanic activity or glacial retreat.Easy
• 3Secondary successionDescribe recovery on land where soil already exists.Why it mattersOccurs after fire, clearance or land abandonment.Easy
• 4Pioneer speciesDescribe the first colonisers of a bare environment.Why it mattersBegin soil formation and habitat modification.Easy
• 5Climax communityDefine the relatively stable end point of succession.Why it mattersThe benchmark against which change is judged.Easy
• 6ZonationDefine spatial variation in communities along a gradient.Why it mattersDistinguished from change over time.Easy

Medium — Applications

• 7Distinguishing zonation from successionExplain change over space against change over time.Why it mattersA distinction examiners test directly.Medium
• 8Changes during successionExplain increasing biomass, diversity and soil depth.Why it mattersThe measurable trends you must describe.Medium
• 9Role of pioneer speciesExplain how early colonisers modify the environment.Why it mattersEnables later species to establish successfully.Medium
• 10Human interruption of successionExplain arrested succession from grazing or burning.Why it mattersExplains persistent grassland and moorland.Medium
• 11Ecosystem resilienceExplain capacity to recover following a disturbance.Why it mattersDetermines long-term ecosystem survival.Medium
• 12Factors affecting resilienceExplain diversity, system size and speed of reproduction.Why it mattersDetermines vulnerability to future disturbance.Medium

Hard — Structured IB

• 13Analysing succession using field dataExamine transect evidence of community change.Why it mattersA required practical investigation in ESS.Hard
• 14Analysing changes in productivity during successionExamine gross productivity relative to respiration.Why it mattersExplains why biomass accumulation eventually slows.Hard
• 15Analysing diversity change during successionExamine why diversity may peak before the climax stage.Why it mattersPrevents assuming diversity rises continuously.Hard
• 16Analysing disturbance regimesExamine the frequency and severity of disturbance events.Why it mattersDetermines which successional stage persists.Hard
• 17Analysing resilience of a named ecosystemExamine specific evidence of recovery capacity.Why it mattersApplies theory to one concrete case.Hard
• 18Analysing the climax community conceptExamine criticism of a single stable end point.Why it mattersModern ecology questions this classical idea.Hard

Very Hard — Integrated SL

• 19Evaluating the succession modelJudge its explanatory value against real complexity.Why it mattersA guaranteed evaluation question in Paper 1.Very Hard
• 20Assessing the resilience of a disturbed ecosystemJudge recovery prospects using field evidence.Why it mattersRewards applied use of specific data.Very Hard
• 21Evaluating human management of successionJudge whether arrested succession is actually desirable.Why it mattersRaises a genuine conservation dilemma.Very Hard
• 22Judging the significance of tipping points in successionEvaluate irreversible change following disturbance.Why it mattersExplains failure of some restoration projects.Very Hard
• 23Integrating succession with conservation planningLink successional stage to management decisions.Why it mattersRewards a synoptic link forward into Chapter 3.Very Hard
• 24Constructing a full succession evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1BiodiversityDefine the variety of life at genetic, species and ecosystem levels.Why it mattersThe organising concept of the whole chapter.Easy
• 2Species diversityDefine the number and relative abundance of species present.Why it mattersThe most commonly measured form of diversity.Easy
• 3Genetic diversityDefine variation in genes within a population.Why it mattersDetermines the capacity to adapt to change.Easy
• 4Habitat diversityDefine the range of different habitats within an area.Why it mattersSupports higher overall species diversity.Easy
• 5Natural selectionDescribe differential survival of favourable inherited variation.Why it mattersThe mechanism driving evolutionary change.Easy
• 6SpeciationDefine the formation of new species from existing populations.Why it mattersExplains how biodiversity is generated over time.Easy

Medium — Applications

• 7Simpson's diversity indexExplain a measure combining species richness and evenness.Why it mattersThe required quantitative diversity measure in ESS.Medium
• 8Calculating Simpson's indexApply the formula to given species abundance data.Why it mattersA guaranteed Paper 2 calculation.Medium
• 9Interpreting diversity index valuesExplain what higher and lower values actually indicate.Why it mattersEnables comparison between sites or over time.Medium
• 10Biodiversity and ecosystem resilienceExplain how diversity buffers a system against disturbance.Why it mattersThe core functional argument for conservation.Medium
• 11Isolation and speciationExplain geographic separation leading to genetic divergence.Why it mattersExplains high endemism found on islands.Medium
• 12Approaches to biodiversity managementExplain in-situ and ex-situ conservation.Why it mattersThe two broad categories of conservation strategy.Medium

Hard — Structured IB

• 13Analysing limitations of diversity indicesExamine what a single summary number conceals.Why it mattersPrevents overreliance on one calculated value.Hard
• 14Analysing sampling methods for biodiversityExamine quadrats, transects and trapping methods.Why it mattersDetermines reliability of any diversity estimate.Hard
• 15Analysing the effect of plate tectonics on biodiversityExamine isolation and continental movement.Why it mattersExplains global patterns of species distribution.Hard
• 16Analysing evidence for evolutionExamine fossil, genetic and directly observed evidence.Why it mattersSupports the mechanism underlying biodiversity.Hard
• 17Analysing rates of natural and current extinctionExamine background rates against present losses.Why it mattersEstablishes the scale of the biodiversity crisis.Hard
• 18Analysing biodiversity hotspotsExamine areas of high endemism that are under threat.Why it mattersGuides prioritisation of conservation effort.Hard

Very Hard — Integrated SL

• 19Evaluating Simpson's diversity indexJudge its usefulness against recognised limitations.Why it mattersA guaranteed Paper 1 evaluation.Very Hard
• 20Assessing methods of measuring biodiversityJudge accuracy against cost and practicality.Why it mattersA standard practical evaluation question.Very Hard
• 21Evaluating the link between diversity and resilienceJudge the strength of the supporting evidence.Why it mattersPrevents asserting a relationship uncritically.Very Hard
• 22Judging conservation prioritiesEvaluate hotspot against flagship-species approaches.Why it mattersRequires prioritisation under limited resources.Very Hard
• 23Integrating biodiversity with ecosystem servicesLink diversity loss to the loss of human benefit.Why it mattersRewards synoptic reasoning across the course.Very Hard
• 24Constructing a full biodiversity evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Threats to biodiversityIdentify habitat loss, overexploitation, pollution and invasive species.Why it mattersThe standard list required in every answer.Easy
• 2Habitat loss and fragmentationDescribe destruction and division of natural habitat.Why it mattersThe single largest driver of biodiversity loss.Easy
• 3OverexploitationDescribe harvesting faster than populations can replace themselves.Why it mattersExplains collapse of fisheries and hunted species.Easy
• 4Invasive speciesDescribe introduced species outcompeting native organisms.Why it mattersA major threat especially on island ecosystems.Easy
• 5ExtinctionDefine the permanent loss of a species from Earth.Why it mattersThe endpoint of unmanaged biodiversity loss.Easy
• 6The IUCN Red ListDescribe the system for assessing species conservation status.Why it mattersThe standard global measure of species threat.Easy

Medium — Applications

• 7Criteria for conservation statusExplain population size, range and rate of decline.Why it mattersDetermines how a species is formally classified.Medium
• 8Factors making species vulnerableExplain small range, low reproductive rate and specialisation.Why it mattersPredicts which species are most at risk.Medium
• 9The tragedy of the commonsExplain overuse of shared and unowned resources.Why it mattersThe main economic explanation of overexploitation.Medium
• 10Climate change as a threatExplain range shifts and increasing habitat unsuitability.Why it mattersAn increasingly dominant biodiversity pressure.Medium
• 11Pollution as a threatExplain toxic, nutrient and plastic impacts on species.Why it mattersLinks biodiversity to Chapters 4 and 8.Medium
• 12Conservation case studiesExplain one named success and one named failure.Why it mattersProvides the evidence every essay requires.Medium

Hard — Structured IB

• 13Analysing the tragedy of the commonsExamine individual incentives against collective interest.Why it mattersExplains why voluntary restraint usually fails.Hard
• 14Analysing edge effects in fragmented habitatExamine altered conditions at habitat boundaries.Why it mattersExplains why fragment area alone is insufficient.Hard
• 15Analysing why some conservation efforts failExamine funding, enforcement and local opposition.Why it mattersPrevents assuming protection guarantees success.Hard
• 16Analysing the limitations of the Red ListExamine data gaps and assessment bias.Why it mattersDetermines confidence in reported conservation status.Hard
• 17Analysing the impact of invasive speciesExamine competition, predation and disease transfer.Why it mattersExplains rapid collapse of native populations.Hard
• 18Analysing economic drivers of biodiversity lossExamine land value, subsidies and market demand.Why it mattersIdentifies the root cause behind proximate threats.Hard

Very Hard — Integrated SL

• 19Evaluating a named conservation case studyJudge success against stated objectives and evidence.Why it mattersA guaranteed extended-response question.Very Hard
• 20Assessing solutions to the tragedy of the commonsJudge regulation, ownership and cooperation.Why it mattersRequires comparison of policy alternatives.Very Hard
• 21Evaluating the relative importance of threatsJudge which pressure matters most for a named species.Why it mattersRequires prioritisation rather than listing.Very Hard
• 22Judging the adequacy of conservation status systemsEvaluate the Red List against its practical limits.Why it mattersTests critical assessment of an institution.Very Hard
• 23Integrating threat analysis with management strategyLink diagnosed pressures to appropriate responses.Why it mattersRewards a synoptic link forward into Unit 3.3.Very Hard
• 24Constructing a full biodiversity threat evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1In-situ conservationDefine protecting species within their natural habitat.Why it mattersThe preferred approach wherever habitat remains.Easy
• 2Ex-situ conservationDefine protecting species outside their natural habitat.Why it mattersUsed where wild populations are no longer viable.Easy
• 3Protected areasDescribe legally designated areas managed for conservation.Why it mattersThe main in-situ conservation tool.Easy
• 4Zoos and captive breedingDescribe ex-situ maintenance and reproduction of species.Why it mattersProvides a last resort for critically endangered species.Easy
• 5Seed banksDescribe long-term storage of plant genetic material.Why it mattersPreserves genetic diversity at very low cost.Easy
• 6RewildingDefine restoring ecosystems through reduced human management.Why it mattersAn increasingly prominent restoration approach.Easy

Medium — Applications

• 7Design of protected areasExplain size, shape, edge effects and corridors.Why it mattersDetermines whether a reserve actually works.Medium
• 8Wildlife corridorsExplain connections allowing movement between fragments.Why it mattersReduces the isolation of small populations.Medium
• 9Buffer zonesExplain transitional areas surrounding a protected core.Why it mattersReduces pressure on the most sensitive habitat.Medium
• 10Species reintroductionExplain returning species to their former range.Why it mattersA central technique in rewilding projects.Medium
• 11Keystone speciesExplain species with disproportionate ecosystem influence.Why it mattersExplains large effects from single reintroductions.Medium
• 12Biodiversity planetary boundaryExplain the safe limit for the rate of biodiversity loss.Why it mattersPlaces conservation within a global limits framework.Medium

Hard — Structured IB

• 13Analysing protected area effectivenessExamine enforcement, funding and local support.Why it mattersExplains the problem of paper parks.Hard
• 14Analysing the role of local communitiesExamine participation and sharing of benefits.Why it mattersDetermines long-term project viability.Hard
• 15Analysing limitations of ex-situ conservationExamine cost, genetic diversity and reintroduction success.Why it mattersPrevents assuming captive breeding is a full solution.Hard
• 16Analysing rewilding outcomesExamine ecological gains against social conflict.Why it mattersExplains opposition from existing land users.Hard
• 17Analysing international conservation agreementsExamine enforcement and national compliance.Why it mattersDetermines whether global rules actually bind.Hard
• 18Analysing conflicting conservation perspectivesExamine ecocentric, anthropocentric and technocentric views.Why it mattersLinks conservation directly back to Chapter 1.Hard

Very Hard — Integrated SL

• 19Evaluating in-situ against ex-situ conservationWeigh effectiveness, cost and feasibility.Why it mattersA guaranteed extended-response comparison.Very Hard
• 20Assessing the design of a named protected areaJudge size, connectivity and management evidence.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating rewilding as a strategyJudge ecological benefit against social cost.Why it mattersRequires balanced treatment of a contested approach.Very Hard
• 22Judging conservation priorities under limited fundingEvaluate competing claims on scarce resources.Why it mattersMirrors real conservation decision-making.Very Hard
• 23Integrating conservation strategy with environmental value systemsLink the chosen approach to an underlying worldview.Why it mattersThe synoptic reasoning examiners reward.Very Hard
• 24Constructing a full conservation evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1The hydrological cycleDefine the continuous movement of water through Earth systems.Why it mattersA closed system driven by solar energy.Easy
• 2Water storagesIdentify oceans, ice, groundwater, lakes and atmosphere.Why it mattersRequired detail for any water cycle diagram.Easy
• 3Water flowsIdentify evaporation, precipitation, infiltration and runoff.Why it mattersThe processes moving water between storages.Easy
• 4EvapotranspirationDefine combined evaporation and plant transpiration.Why it mattersA major flow returning water to the atmosphere.Easy
• 5Groundwater and aquifersDescribe water stored within permeable rock.Why it mattersA major but slowly replenished freshwater store.Easy
• 6Drawing a hydrological cycle diagramConstruct a labelled systems diagram of water.Why it mattersA guaranteed Paper 1 diagram.Easy

Medium — Applications

• 7Residence time of water storesExplain how long water remains in each storage.Why it mattersDetermines how quickly a store can be depleted.Medium
• 8Human impacts on infiltrationExplain how urbanisation reduces water absorption.Why it mattersExplains increased flood risk in cities.Medium
• 9Deforestation and the water cycleExplain reduced interception and evapotranspiration.Why it mattersAlters both local rainfall and surface runoff.Medium
• 10Dams and reservoirsExplain artificial alteration of water storage and flow.Why it mattersA major human modification of the cycle.Medium
• 11Irrigation and water abstractionExplain removal of water for agricultural use.Why it mattersThe largest single human use of freshwater.Medium
• 12Groundwater depletionExplain extraction exceeding the rate of natural recharge.Why it mattersExplains falling water tables worldwide.Medium

Hard — Structured IB

• 13Analysing the effect of land use change on runoffExamine surface sealing and vegetation removal.Why it mattersExplains flash flooding in modified catchments.Hard
• 14Analysing salinisation from irrigationExamine salt accumulation in irrigated soils.Why it mattersLinks water management directly to Chapter 5.Hard
• 15Analysing the impact of dams on downstream systemsExamine sediment, flow and ecosystem effects.Why it mattersA frequently examined environmental trade-off.Hard
• 16Analysing climate change effects on the water cycleExamine altered precipitation and glacier melt.Why it mattersConnects water systems to Chapter 6.Hard
• 17Analysing aquifer recharge ratesExamine the sustainability of groundwater extraction.Why it mattersDetermines whether use is genuinely renewable.Hard
• 18Analysing water cycle dataInterpret storage and flow figures from a diagram.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating the sustainability of groundwater useJudge extraction rates against recharge evidence.Why it mattersA guaranteed evaluation question.Very Hard
• 20Assessing the impacts of a named dam projectJudge benefits against ecological and social costs.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating human modification of the water cycleJudge the overall balance of benefits and harms.Why it mattersRequires genuinely two-sided reasoning.Very Hard
• 22Judging the vulnerability of a named catchmentEvaluate pressures using specific evidence.Why it mattersApplies systems analysis to a real place.Very Hard
• 23Integrating the water cycle with food productionLink water availability to agricultural viability.Why it mattersRewards a synoptic link forward into Chapter 5.Very Hard
• 24Constructing a full hydrological evaluationBuild a diagram-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Water securityDefine reliable access to sufficient safe water.Why it mattersThe organising concept of this topic.Easy
• 2Water scarcityDefine insufficient water available to meet demand.Why it mattersThe condition water management aims to prevent.Easy
• 3Physical and economic scarcityDistinguish absence of water from inability to access it.Why it mattersA distinction examiners test directly.Easy
• 4Global distribution of freshwaterDescribe the uneven availability of accessible water.Why it mattersExplains why scarcity is regional rather than global.Easy
• 5Sectors of water useIdentify agricultural, industrial and domestic demand.Why it mattersAgriculture dominates global water withdrawal.Easy
• 6Factors controlling access to freshwaterIdentify climate, geology, infrastructure and wealth.Why it mattersExplains variation in water security between places.Easy

Medium — Applications

• 7DesalinationExplain the removal of salt to produce freshwater.Why it mattersA technocentric solution to physical scarcity.Medium
• 8Rainwater harvestingExplain local collection and storage of rainfall.Why it mattersA low-cost small-scale supply strategy.Medium
• 9Water transfer schemesExplain moving water between catchments.Why it mattersRedistributes supply at large scale and high cost.Medium
• 10Water conservation strategiesExplain efficiency, pricing and leak reduction.Why it mattersReduces demand rather than raising supply.Medium
• 11Grey water recyclingExplain reuse of lightly used domestic water.Why it mattersExtends supply without new abstraction.Medium
• 12Water conflictsExplain disputes over shared transboundary resources.Why it mattersExplains international tension over major rivers.Medium

Hard — Structured IB

• 13Analysing the costs of desalinationExamine energy demand, brine disposal and expense.Why it mattersDetermines feasibility beyond wealthy states.Hard
• 14Analysing demand management against supply expansionExamine effectiveness and long-term sustainability.Why it mattersThe central strategic choice in water policy.Hard
• 15Analysing virtual water and tradeExamine water embedded within traded goods.Why it mattersReveals hidden water flows between countries.Hard
• 16Analysing water pricing as a management toolExamine efficiency gains against equity concerns.Why it mattersRaises access issues for poorer households.Hard
• 17Analysing the causes of water conflictExamine upstream and downstream competing claims.Why it mattersExplains persistent transboundary disputes.Hard
• 18Analysing water security dataInterpret availability and consumption statistics.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating desalination as a solutionJudge reliability against cost and environmental impact.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing strategies for a named water-scarce regionJudge options against local conditions and cost.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating water conservation against new supplyWeigh demand reduction against building infrastructure.Why it mattersRequires comparison of two strategic approaches.Very Hard
• 22Judging the fairness of water allocationEvaluate competing sectoral and national claims.Why it mattersConnects water management to environmental justice.Very Hard
• 23Integrating water security with climate changeLink changing precipitation to future availability.Why it mattersRewards a synoptic link forward into Chapter 6.Very Hard
• 24Constructing a full water security evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Aquatic food websDescribe feeding relationships in marine and freshwater systems.Why it mattersThe ecological basis of fisheries management.Easy
• 2PhytoplanktonDescribe microscopic producers at the base of ocean food webs.Why it mattersSupport almost all marine productivity.Easy
• 3Areas of high marine productivityIdentify upwelling zones and continental shelves.Why it mattersExplains where the world's fisheries are located.Easy
• 4Maximum sustainable yieldDefine the largest catch that can be taken indefinitely.Why it mattersThe theoretical target of fisheries management.Easy
• 5OverfishingDefine harvesting faster than stocks can replace themselves.Why it mattersThe main cause of global fishery decline.Easy
• 6AquacultureDefine the farming of aquatic organisms.Why it mattersThe fastest growing food production sector.Easy

Medium — Applications

• 7Causes of overexploitationExplain demand, improved technology and open access.Why it mattersLinks fisheries directly to the tragedy of the commons.Medium
• 8Consequences of overfishingExplain stock collapse and food web disruption.Why it mattersExplains the failure of named historic fisheries.Medium
• 9Fishing quotas and regulationExplain limits on catch, gear type and season.Why it mattersThe main regulatory mitigation approach.Medium
• 10Marine protected areasExplain reserves allowing fish stocks to recover.Why it mattersA spatial approach to fisheries recovery.Medium
• 11Impacts of aquacultureExplain pollution, disease and escape of farmed species.Why it mattersAquaculture creates its own environmental problems.Medium
• 12Ocean acidificationExplain falling ocean pH from dissolved carbon dioxide.Why it mattersThreatens shell-forming organisms and coral reefs.Medium

Hard — Structured IB

• 13Analysing the limitations of maximum sustainable yieldExamine data uncertainty and stock variability.Why it mattersExplains why quotas are often set too high.Hard
• 14Analysing bycatch and gear impactsExamine non-target mortality and habitat damage.Why it mattersA major but frequently overlooked fisheries impact.Hard
• 15Analysing the effectiveness of quotasExamine enforcement, discarding and compliance.Why it mattersDetermines whether regulation actually works.Hard
• 16Analysing climate change effects on fisheriesExamine warming, range shift and productivity change.Why it mattersConnects fisheries directly to Chapter 6.Hard
• 17Analysing the effects of ocean acidificationExamine impacts on calcifying organisms and reefs.Why it mattersExplains predicted marine ecosystem change.Hard
• 18Analysing the sustainability of aquaculture systemsExamine feed inputs, siting and waste outputs.Why it mattersDetermines whether farming genuinely reduces pressure.Hard

Very Hard — Integrated SL

• 19Evaluating aquaculture as a solution to overfishingJudge production gains against environmental costs.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing the effectiveness of marine protected areasJudge recovery evidence against enforcement problems.Why it mattersRewards applied use of named examples.Very Hard
• 21Evaluating a named fishery management strategyJudge outcomes against its stated objectives.Why it mattersRequires critical use of specific evidence.Very Hard
• 22Judging the severity of ocean acidificationEvaluate projected impacts against scientific uncertainty.Why it mattersRequires careful handling of model predictions.Very Hard
• 23Integrating fisheries management with the commons problemLink resource ownership to sustainable outcomes.Why it mattersRewards a synoptic link back into Chapter 3.Very Hard
• 24Constructing a full aquatic food production evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Water pollutionDefine the addition of substances that degrade water quality.Why it mattersThe organising concept of this topic.Easy
• 2Point and non-point sourcesDistinguish identifiable discharge from diffuse sources.Why it mattersDetermines how pollution can be regulated.Easy
• 3Sources of water contaminationIdentify sewage, agriculture, industry and urban runoff.Why it mattersThe named sources required in written answers.Easy
• 4Plastic pollutionDescribe accumulation of persistent plastic in water bodies.Why it mattersA rapidly growing and highly visible problem.Easy
• 5MicroplasticsDefine very small plastic fragments entering food webs.Why it mattersEnter organisms and accumulate up the food chain.Easy
• 6EutrophicationDefine nutrient enrichment causing excessive plant growth.Why it mattersThe most commonly examined water pollution process.Easy

Medium — Applications

• 7The process of eutrophicationExplain nutrient input, algal bloom, decomposition and oxygen loss.Why it mattersThe full sequence required for full marks.Medium
• 8Biochemical oxygen demandExplain oxygen consumed by decomposing organic matter.Why it mattersA direct chemical indicator of organic pollution.Medium
• 9Indicator speciesExplain organisms whose presence signals water quality.Why it mattersA biotic method of assessing pollution.Medium
• 10Biotic indicesExplain scoring systems based on species sensitivity.Why it mattersConverts biological data into a water quality score.Medium
• 11Monitoring water qualityExplain chemical, biological and physical measurement.Why it mattersThe evidence base for pollution management.Medium
• 12Levels of pollution managementExplain altering activity, controlling release and clean-up.Why it mattersThe three-level framework required in ESS.Medium

Hard — Structured IB

• 13Analysing the consequences of eutrophicationExamine oxygen depletion, fish death and biodiversity loss.Why it mattersThe applied significance of the process.Hard
• 14Analysing strategies to reduce eutrophicationExamine fertiliser control, buffer zones and treatment.Why it mattersApplies the three-level management framework.Hard
• 15Analysing the limitations of indicator speciesExamine confounding factors and identification difficulty.Why it mattersDetermines reliability of biotic assessment.Hard
• 16Analysing plastic pollution pathwaysExamine sources, transport and accumulation zones.Why it mattersExplains ocean gyre plastic concentration.Hard
• 17Analysing sewage treatment processesExamine primary, secondary and tertiary treatment.Why it mattersThe main technological pollution response.Hard
• 18Analysing water quality dataInterpret oxygen, nutrient and biotic index figures.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating strategies to manage eutrophicationJudge effectiveness, cost and feasibility together.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing methods of monitoring water qualityJudge chemical against biological approaches.Why it mattersA standard practical evaluation question.Very Hard
• 21Evaluating responses to plastic pollutionJudge prevention, regulation and clean-up options.Why it mattersApplies the pollution management framework.Very Hard
• 22Judging the most effective level of pollution managementEvaluate prevention against treatment approaches.Why it mattersRequires prioritisation with clear justification.Very Hard
• 23Integrating pollution management with agricultural policyLink nutrient control to farming practice.Why it mattersRewards a synoptic link forward into Chapter 5.Very Hard
• 24Constructing a full water pollution evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Soil as a systemDefine soil as a dynamic system with inputs, storages and outputs.Why it mattersApplies systems thinking to the land surface.Easy
• 2Composition of soilIdentify mineral particles, organic matter, water and air.Why it mattersThe four components present in any soil.Easy
• 3Soil horizonsDescribe the layered structure of a soil profile.Why it mattersA required diagram in Paper 1.Easy
• 4Soil textureDefine the proportion of sand, silt and clay particles.Why it mattersDetermines drainage and nutrient retention.Easy
• 5The soil texture triangleInterpret the diagram to classify a soil sample.Why it mattersA guaranteed practical data skill.Easy
• 6Soil formationDescribe weathering and organic accumulation over time.Why it mattersExplains why soil is effectively non-renewable.Easy

Medium — Applications

• 7Properties of sand, silt and clay soilsExplain differences in drainage, aeration and fertility.Why it mattersDetermines agricultural suitability of a soil.Medium
• 8Loam soilsExplain why balanced texture supports productive agriculture.Why it mattersThe most agriculturally valuable soil type.Medium
• 9Soil functions in ecosystemsExplain support, nutrient supply, water storage and carbon storage.Why it mattersLinks soil directly to other ESS chapters.Medium
• 10Primary productivity and soilExplain how soil quality limits plant growth.Why it mattersConnects soil to energy flow in ecosystems.Medium
• 11Soil and the carbon cycleExplain soil as a major terrestrial carbon store.Why it mattersLinks soil management to climate change.Medium
• 12Soil biotaExplain the role of decomposers and other soil organisms.Why it mattersDrive nutrient cycling within the soil system.Medium

Hard — Structured IB

• 13Analysing soil degradationExamine erosion, compaction, salinisation and nutrient loss.Why it mattersThe main threats to soil productivity.Hard
• 14Analysing causes of soil erosionExamine vegetation removal, overgrazing and cultivation.Why it mattersIdentifies the practices that must change.Hard
• 15Analysing desertificationExamine climate and human causes of land degradation.Why it mattersA major global land management problem.Hard
• 16Analysing soil conservation techniquesExamine terracing, contour ploughing and windbreaks.Why it mattersThe applied management content of this topic.Hard
• 17Analysing soil fertility managementExamine organic and inorganic nutrient inputs.Why it mattersLinks soil management to eutrophication risk.Hard
• 18Analysing soil dataInterpret texture, pH and organic content measurements.Why it mattersA standard practical data task.Hard

Very Hard — Integrated SL

• 19Evaluating soil conservation strategiesJudge effectiveness, cost and applicability.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing the sustainability of a named soil management practiceJudge long-term productivity against short-term yield.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating soil as a renewable resourceJudge rates of formation against rates of loss.Why it mattersDetermines whether current use is sustainable.Very Hard
• 22Judging the severity of soil degradationEvaluate the evidence for a named region.Why it mattersRequires critical use of data.Very Hard
• 23Integrating soil management with food securityLink soil quality to long-term food production.Why it mattersRewards a synoptic link forward into Unit 5.2.Very Hard
• 24Constructing a full soil systems evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Food securityDefine reliable access to sufficient safe and nutritious food.Why it mattersThe organising concept of this topic.Easy
• 2Agricultural systems as systemsIdentify the inputs, processes and outputs of farming.Why it mattersApplies systems thinking to food production.Easy
• 3Subsistence and commercial farmingDistinguish farming for consumption from farming for sale.Why it mattersA basic classification of agricultural systems.Easy
• 4Intensive and extensive farmingDistinguish high input per area from low input per area.Why it mattersDetermines yield and environmental impact.Easy
• 5Terrestrial food production systemsIdentify arable, pastoral and mixed farming systems.Why it mattersThe named types required in comparisons.Easy
• 6Traditional farming practicesDescribe low-input methods using local knowledge.Why it mattersOften more sustainable but lower yielding.Easy

Medium — Applications

• 7Modern industrial agricultureExplain mechanisation, fertiliser use and monoculture.Why it mattersThe dominant system in developed economies.Medium
• 8The Green RevolutionExplain high-yield varieties and their associated inputs.Why it mattersTransformed yields but raised input dependence.Medium
• 9Environmental impacts of intensive agricultureExplain soil, water and biodiversity consequences.Why it mattersThe environmental cost of higher yields.Medium
• 10Organic and agroecological farmingExplain reduced synthetic inputs and ecological methods.Why it mattersThe main lower-impact alternative system.Medium
• 11Factors influencing food securityExplain production, distribution, access and stability.Why it mattersShows food security is more than total output.Medium
• 12Food wasteExplain losses in production, distribution and consumption.Why it mattersA major and avoidable pressure on food systems.Medium

Hard — Structured IB

• 13Comparing the sustainability of two food systemsAnalyse inputs, outputs and environmental impact.Why it mattersA guaranteed comparison question in ESS.Hard
• 14Analysing energy efficiency of food productionExamine energy input per unit of food output.Why it mattersLinks food systems to energy flow theory.Hard
• 15Analysing the impacts of monocultureExamine pest vulnerability and biodiversity loss.Why it mattersExplains dependence on pesticide inputs.Hard
• 16Analysing livestock production impactsExamine land, water and emissions per unit of protein.Why it mattersA central issue in dietary change debates.Hard
• 17Analysing distribution and access to foodExamine why hunger persists despite sufficient production.Why it mattersShifts the focus from output to equity.Hard
• 18Analysing climate change effects on food securityExamine yield, water and extreme event impacts.Why it mattersConnects food systems to Chapter 6.Hard

Very Hard — Integrated SL

• 19Evaluating the sustainability of industrial agricultureJudge yield against environmental and social cost.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing organic farming as an alternativeJudge lower impact against lower yields and land use.Why it mattersRequires balanced two-sided reasoning.Very Hard
• 21Evaluating strategies to improve food securityJudge production, distribution and waste approaches.Why it mattersRequires comparison of policy options.Very Hard
• 22Judging the case for dietary changeEvaluate efficiency arguments against cultural factors.Why it mattersApplies energy flow to a contemporary debate.Very Hard
• 23Integrating food systems with soil and water managementBuild one combined sustainability argument.Why it mattersThe synoptic reasoning examiners reward.Very Hard
• 24Constructing a full food security evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Composition of the atmosphereIdentify nitrogen, oxygen and trace gases including carbon dioxide.Why it mattersThe baseline for all atmospheric analysis.Easy
• 2Structure of the atmosphereIdentify the troposphere and the stratosphere.Why it mattersDistinguishes weather from ozone processes.Easy
• 3Functions of the atmosphereDescribe its role in temperature regulation and radiation filtering.Why it mattersExplains why atmospheric change matters so much.Easy
• 4The greenhouse effectDefine the natural warming caused by atmospheric gases.Why it mattersA natural process essential to life on Earth.Easy
• 5Greenhouse gasesIdentify carbon dioxide, methane, water vapour and nitrous oxide.Why it mattersThe gases responsible for the effect.Easy
• 6Shortwave and longwave radiationDistinguish incoming solar from outgoing terrestrial radiation.Why it mattersThe key to explaining the greenhouse mechanism.Easy

Medium — Applications

• 7The mechanism of the greenhouse effectExplain absorption and re-emission of longwave radiation.Why it mattersThe full explanation required for full marks.Medium
• 8The energy budget of the atmosphereExplain the balance of incoming and outgoing radiation.Why it mattersExplains why the planet has a stable temperature.Medium
• 9AlbedoExplain the proportion of radiation reflected by a surface.Why it mattersDetermines how much energy is actually absorbed.Medium
• 10Natural against enhanced greenhouse effectDistinguish the essential process from human intensification.Why it mattersA distinction examiners test directly.Medium
• 11Global warming potentialExplain the relative warming effect of different gases.Why it mattersExplains why methane matters despite low concentration.Medium
• 12Residence time of greenhouse gasesExplain how long each gas remains in the atmosphere.Why it mattersDetermines the persistence of emissions.Medium

Hard — Structured IB

• 13Analysing the enhanced greenhouse effectExamine how human emissions intensify natural warming.Why it mattersThe core causal mechanism of climate change.Hard
• 14Analysing the ice-albedo feedbackExamine melting ice reducing surface reflectivity.Why it mattersA key positive feedback in polar regions.Hard
• 15Analysing sources of greenhouse gasesExamine combustion, agriculture and land use change.Why it mattersIdentifies where mitigation must be targeted.Hard
• 16Analysing atmospheric dataInterpret trends in measured gas concentration.Why it mattersA standard data-response task.Hard
• 17Analysing the role of water vapourExamine its feedback role in atmospheric warming.Why it mattersA powerful but often misunderstood factor.Hard
• 18Analysing energy budget diagramsExamine flows of incoming and outgoing radiation.Why it mattersA guaranteed Paper 1 diagram skill.Hard

Very Hard — Integrated SL

• 19Evaluating the evidence for the enhanced greenhouse effectJudge the strength of observational and model evidence.Why it mattersPrepares you for evidence-based argument.Very Hard
• 20Assessing the relative importance of greenhouse gasesJudge concentration against warming potential.Why it mattersRequires combining two variables in one judgement.Very Hard
• 21Evaluating the role of feedback in atmospheric changeJudge how feedback amplifies initial warming.Why it mattersExplains the urgency in climate projections.Very Hard
• 22Judging the reliability of atmospheric measurementsEvaluate data sources and length of record.Why it mattersDetermines confidence in observed trends.Very Hard
• 23Integrating atmospheric processes with the carbon cycleLink emissions to storage and flow changes.Why it mattersRewards a synoptic link back into Chapter 2.Very Hard
• 24Constructing a full atmospheric systems evaluationBuild a diagram-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Climate changeDefine long-term change in average climate conditions.Why it mattersDistinguished from short-term weather variation.Easy
• 2Natural causes of climate changeIdentify volcanic activity, solar variation and orbital change.Why it mattersThe baseline against which human effects are judged.Easy
• 3Human drivers of climate changeIdentify fossil fuel combustion, deforestation and agriculture.Why it mattersThe dominant cause of recent warming.Easy
• 4Evidence for climate changeIdentify temperature records, ice cores and sea level data.Why it mattersThe observational basis of climate science.Easy
• 5Ice cores as evidenceDescribe trapped air revealing past atmospheric composition.Why it mattersExtends the record far beyond instruments.Easy
• 6Impacts on ecosystemsIdentify range shifts, phenology change and coral bleaching.Why it mattersThe ecological consequences of warming.Easy

Medium — Applications

• 7Sea level riseExplain thermal expansion and melting land ice.Why it mattersTwo distinct mechanisms required for full marks.Medium
• 8Changes in precipitation patternsExplain altered rainfall distribution and intensity.Why it mattersDrives both flooding and drought.Medium
• 9Extreme weather eventsExplain increased frequency and intensity of events.Why it mattersThe most visible human impact of warming.Medium
• 10Coral bleachingExplain loss of symbiotic algae under thermal stress.Why it mattersThreatens the most biodiverse marine ecosystem.Medium
• 11Social consequences of climate changeExplain health, displacement and migration effects.Why it mattersThe human dimension of climate impact.Medium
• 12Economic consequences of climate changeExplain agriculture, infrastructure and insurance costs.Why it mattersExplains the economic case for mitigation.Medium

Hard — Structured IB

• 13Analysing climate modelsExamine assumptions, scenarios and uncertainty.Why it mattersDetermines confidence in future projections.Hard
• 14Analysing feedback mechanisms in climate changeExamine permafrost, albedo and carbon sink loss.Why it mattersExplains the risk of accelerating change.Hard
• 15Analysing regional variation in impactsExamine why some regions suffer far more than others.Why it mattersIntroduces climate justice considerations.Hard
• 16Analysing tipping points in the climate systemExamine thresholds for irreversible change.Why it mattersExplains the case for urgent action.Hard
• 17Analysing climate data setsInterpret temperature, sea level and emissions trends.Why it mattersA guaranteed Paper 2 data task.Hard
• 18Analysing vulnerability and adaptive capacityExamine why poorer regions are more exposed.Why it mattersLinks climate impact directly to development.Hard

Very Hard — Integrated SL

• 19Evaluating the evidence for human-caused climate changeJudge multiple independent lines of evidence together.Why it mattersA guaranteed extended-response question.Very Hard
• 20Assessing the reliability of climate projectionsJudge model uncertainty against consistency of findings.Why it mattersRequires careful handling of scientific uncertainty.Very Hard
• 21Evaluating the impacts on a named regionJudge ecological and social consequences with evidence.Why it mattersRewards applied use of a specific case.Very Hard
• 22Judging responsibility for climate changeEvaluate historic emitters against current emitters.Why it mattersRaises a contested global equity issue.Very Hard
• 23Integrating climate impacts with biodiversity and food systemsBuild one combined argument across chapters.Why it mattersThe synoptic reasoning examiners reward.Very Hard
• 24Constructing a full climate change evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1MitigationDefine reducing the causes of climate change.Why it mattersOne of the two categories of climate response.Easy
• 2AdaptationDefine adjusting to the effects of climate change.Why it mattersThe second category of climate response.Easy
• 3DecarbonisationDefine reducing carbon emissions from energy and industry.Why it mattersThe central mitigation objective.Easy
• 4Renewable energy as mitigationDescribe low-carbon electricity generation.Why it mattersThe main technological mitigation route.Easy
• 5Carbon sequestrationDefine capture and long-term storage of carbon.Why it mattersRemoves carbon that has already been emitted.Easy
• 6International climate agreementsIdentify the major global climate accords.Why it mattersThe framework for coordinated global action.Easy

Medium — Applications

• 7Emissions trading schemesExplain market-based limits on total emissions.Why it mattersPrices carbon without setting a fixed tax rate.Medium
• 8Carbon taxesExplain charges on emissions designed to change behaviour.Why it mattersAn alternative price-based mitigation instrument.Medium
• 9Energy efficiency measuresExplain reducing demand for the same level of service.Why it mattersOften the cheapest mitigation option available.Medium
• 10Nature-based solutionsExplain reforestation and wetland restoration.Why it mattersMitigation with additional biodiversity benefits.Medium
• 11Adaptation strategiesExplain flood defence, drought-resistant crops and relocation.Why it mattersNecessary even under successful mitigation.Medium
• 12Geoengineering proposalsExplain large-scale deliberate climate intervention.Why it mattersA technocentric and highly contested approach.Medium

Hard — Structured IB

• 13Analysing barriers to international agreementExamine free riding, enforcement and national interest.Why it mattersExplains slow progress towards global targets.Hard
• 14Analysing mitigation against adaptationExamine cost, timing and equity of each approach.Why it mattersThe central strategic choice in climate policy.Hard
• 15Analysing the effectiveness of carbon pricingExamine coverage, price level and emissions leakage.Why it mattersDetermines whether the instrument actually works.Hard
• 16Analysing the risks of geoengineeringExamine uncertainty, governance and moral hazard.Why it mattersExplains scientific caution about intervention.Hard
• 17Analysing adaptation in vulnerable regionsExamine capacity, funding and technical constraints.Why it mattersLinks climate response directly to development.Hard
• 18Analysing the role of individual actionExamine scale of impact relative to systemic change.Why it mattersPrevents overstating personal behaviour change.Hard

Very Hard — Integrated SL

• 19Evaluating mitigation against adaptation strategiesJudge effectiveness, cost and equity together.Why it mattersA guaranteed extended-response comparison.Very Hard
• 20Assessing the effectiveness of a named climate agreementJudge outcomes against its stated targets.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating geoengineering as a responseJudge its potential against uncertainty and risk.Why it mattersRequires balanced treatment of a contested option.Very Hard
• 22Judging climate responses from different value systemsEvaluate ecocentric, anthropocentric and technocentric responses.Why it mattersLinks climate policy back to Chapter 1.Very Hard
• 23Integrating climate response with energy policyLink decarbonisation to energy system choices.Why it mattersRewards a synoptic link forward into Chapter 7.Very Hard
• 24Constructing a full climate response evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Ultraviolet radiationDefine high-energy solar radiation harmful to living tissue.Why it mattersExplains why ozone protection matters.Easy
• 2Stratospheric ozoneDefine the ozone layer absorbing incoming UV radiation.Why it mattersA natural protective filter for life on Earth.Easy
• 3Distinguishing stratospheric and tropospheric ozoneExplain beneficial ozone above and harmful ozone below.Why it mattersA distinction examiners test directly.Easy
• 4Formation of ozoneDescribe the splitting and recombination of oxygen molecules.Why it mattersThe natural process maintaining the layer.Easy
• 5Ozone-depleting substancesIdentify CFCs and other halogenated compounds.Why it mattersThe substances the Montreal Protocol controls.Easy
• 6The Montreal ProtocolDescribe the international agreement phasing out ODS.Why it mattersThe most successful environmental treaty to date.Easy

Medium — Applications

• 7The mechanism of ozone depletionExplain halogen radicals catalytically destroying ozone.Why it mattersThe full chemical explanation required for marks.Medium
• 8Polar ozone depletionExplain why loss is greatest over Antarctica.Why it mattersExplains the seasonal ozone hole.Medium
• 9Effects of increased UV on humansExplain skin cancer, cataracts and immune suppression.Why it mattersThe direct human health consequence.Medium
• 10Effects of increased UV on ecosystemsExplain damage to phytoplankton and plant growth.Why it mattersThreatens the base of marine food webs.Medium
• 11Alternatives to ozone-depleting substancesExplain replacement compounds and technologies.Why it mattersMade the phase-out technically feasible.Medium
• 12Monitoring ozone concentrationExplain satellite and ground-based measurement.Why it mattersProvides the evidence of recovery.Medium

Hard — Structured IB

• 13Analysing the success of the Montreal ProtocolExamine participation, enforcement and measured recovery.Why it mattersThe benchmark case of effective global action.Hard
• 14Comparing ozone and climate agreementsAnalyse why one succeeded far more readily than the other.Why it mattersA frequent and revealing comparison question.Hard
• 15Analysing the persistence of ozone-depleting substancesExamine their long atmospheric residence times.Why it mattersExplains delayed recovery of the layer.Hard
• 16Analysing the interaction of ozone and climate changeExamine overlapping atmospheric processes.Why it mattersSome replacements are potent greenhouse gases.Hard
• 17Analysing ozone monitoring dataInterpret trends in measured ozone concentration.Why it mattersA standard data-response task.Hard
• 18Analysing pollution management levels for ODSExamine prevention, regulation and clean-up options.Why it mattersApplies the ESS management framework.Hard

Very Hard — Integrated SL

• 19Evaluating the Montreal ProtocolJudge its success against remaining limitations.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing why ozone action succeededJudge the role of alternatives, evidence and cost.Why it mattersExplains lessons for climate negotiation.Very Hard
• 21Evaluating the severity of remaining ozone riskJudge recovery evidence against continuing threats.Why it mattersPrevents assuming the problem is fully solved.Very Hard
• 22Judging the transferability of the Montreal modelEvaluate whether the approach suits climate policy.Why it mattersRequires careful comparison of two problems.Very Hard
• 23Integrating ozone policy with climate policyLink the two atmospheric issues in one argument.Why it mattersRewards synoptic atmospheric reasoning.Very Hard
• 24Constructing a full ozone evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Natural capitalDefine natural resources producing a flow of goods and services.Why it mattersThe economic framing of the environment.Easy
• 2Natural incomeDefine the sustainable yield obtained from natural capital.Why it mattersDetermines the safe rate of resource use.Easy
• 3Renewable resourcesDefine resources replenished within a human timescale.Why it mattersCan be used indefinitely if managed properly.Easy
• 4Non-renewable resourcesDefine resources not replaced on a human timescale.Why it mattersUse inevitably depletes the total stock.Easy
• 5Replenishable resourcesDefine resources restored by natural processes if managed.Why it mattersAn intermediate category examiners expect you to know.Easy
• 6Ecosystem servicesIdentify provisioning, regulating, supporting and cultural services.Why it mattersThe benefits people obtain from ecosystems.Easy

Medium — Applications

• 7Sustainable yieldExplain harvesting at or below the rate of replacement.Why it mattersThe operational rule for renewable resource use.Medium
• 8Calculating sustainable yieldApply the difference between annual growth and harvest.Why it mattersA standard quantitative task in ESS.Medium
• 9Valuing natural capitalExplain market, non-market and intangible valuation.Why it mattersDetermines whether nature enters decision-making.Medium
• 10Difficulties in valuing natureExplain the problem of pricing aesthetic and cultural value.Why it mattersA guaranteed evaluation point in this topic.Medium
• 11Dynamic nature of natural capital valueExplain how value changes with technology and culture.Why it mattersExplains why resource importance shifts over time.Medium
• 12Resource securityExplain reliable long-term access to essential resources.Why it mattersLinks resource management to national policy.Medium

Hard — Structured IB

• 13Analysing the consequences of exceeding sustainable yieldExamine stock decline and eventual collapse.Why it mattersExplains failure of named resource systems.Hard
• 14Analysing methods of resource valuationExamine cost-benefit analysis and its assumptions.Why it mattersDetermines what actually gets counted in decisions.Hard
• 15Analysing the influence of value systems on resource useExamine ecocentric against technocentric responses.Why it mattersLinks resource management back to Chapter 1.Hard
• 16Analysing resource ownership and managementExamine private, state and common ownership outcomes.Why it mattersDetermines incentives for sustainable use.Hard
• 17Analysing links between resource security and conflictExamine competition over increasingly scarce resources.Why it mattersExplains geopolitical tension over resources.Hard
• 18Analysing resource use dataInterpret consumption and remaining reserve figures.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating natural capital valuationJudge decision-making usefulness against ethical objections.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing the sustainability of a named resource systemJudge harvest rates against replacement evidence.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating cost-benefit analysis for environmental decisionsJudge rigour against omitted intangible values.Why it mattersRequires balanced methodological reasoning.Very Hard
• 22Judging ownership models for common resourcesEvaluate private, state and community management.Why it mattersConnects resource policy to the commons problem.Very Hard
• 23Integrating resource management with sustainability indicatorsLink use rates to measured sustainability.Why it mattersRewards a synoptic link back into Chapter 1.Very Hard
• 24Constructing a full natural resource evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Energy resourcesIdentify fossil, nuclear and renewable energy sources.Why it mattersThe named sources required in every comparison.Easy
• 2Fossil fuelsDescribe coal, oil and gas formed from ancient organic matter.Why it mattersStill the dominant global energy source.Easy
• 3Nuclear powerDescribe electricity generated from nuclear fission.Why it mattersLow carbon but carrying distinctive risks.Easy
• 4Solar and wind energyDescribe electricity generated from sunlight and air movement.Why it mattersThe fastest growing renewable sources.Easy
• 5Hydroelectric powerDescribe electricity generated from moving water.Why it mattersThe largest established renewable source.Easy
• 6Biomass and biofuelsDescribe energy released from organic material.Why it mattersRenewable but with significant land use implications.Easy

Medium — Applications

• 7Energy securityExplain reliable and affordable access to energy supply.Why it mattersA key driver of national energy policy.Medium
• 8Patterns of energy consumptionExplain variation by wealth, industry and climate.Why it mattersExplains huge differences in per capita use.Medium
• 9Factors affecting energy choicesExplain availability, cost, technology and value systems.Why it mattersDetermines the energy mix a country adopts.Medium
• 10Energy conservationExplain reducing demand through efficiency and behaviour.Why it mattersOften the cheapest energy strategy available.Medium
• 11Energy storageExplain batteries, pumped storage and hydrogen.Why it mattersSolves the intermittency problem of renewables.Medium
• 12Carbon intensity of energy sourcesExplain emissions produced per unit of energy generated.Why it mattersThe key measure for climate policy.Medium

Hard — Structured IB

• 13Comparing sustainability of energy sourcesAnalyse emissions, land use, waste and reliability.Why it mattersA guaranteed comparison question in ESS.Hard
• 14Analysing the intermittency problemExamine variable output from wind and solar.Why it mattersThe main technical barrier to renewables.Hard
• 15Analysing the risks of nuclear powerExamine waste, accidents and decommissioning.Why it mattersExplains public and political opposition.Hard
• 16Analysing impacts of hydroelectric schemesExamine displacement, sediment and ecosystem change.Why it mattersA renewable source with major local impacts.Hard
• 17Analysing biofuel land use competitionExamine food against fuel land allocation.Why it mattersA significant unintended consequence.Hard
• 18Analysing energy dataInterpret consumption, mix and emissions statistics.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating the sustainability of a named energy sourceJudge environmental, economic and social factors.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing nuclear power as a climate solutionJudge low emissions against waste and accident risk.Why it mattersRequires balanced treatment of a contested option.Very Hard
• 21Evaluating an energy strategy for a named countryJudge options against available resources and demand.Why it mattersRewards applied use of a specific case.Very Hard
• 22Judging energy conservation against new generationEvaluate demand reduction against supply expansion.Why it mattersRequires comparison of two strategic approaches.Very Hard
• 23Integrating energy choices with climate mitigationLink the energy mix to emissions outcomes.Why it mattersRewards a synoptic link back into Chapter 6.Very Hard
• 24Constructing a full energy evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Solid domestic wasteDefine discarded material from households and similar sources.Why it mattersThe waste stream most directly examined in ESS.Easy
• 2Types of wasteIdentify organic, plastic, paper, metal, glass and electronic waste.Why it mattersThe composition determining treatment options.Easy
• 3Sources of wasteIdentify domestic, industrial, agricultural and construction waste.Why it mattersDetermines where reduction must be targeted.Easy
• 4LandfillDescribe burial of waste in engineered sites.Why it mattersStill the dominant global disposal method.Easy
• 5IncinerationDescribe combustion of waste, sometimes with energy recovery.Why it mattersReduces volume but produces emissions.Easy
• 6RecyclingDefine reprocessing waste materials into new products.Why it mattersThe main resource recovery strategy.Easy

Medium — Applications

• 7Impacts of landfillExplain leachate, methane release and land occupation.Why it mattersThe environmental cost of burial.Medium
• 8Impacts of incinerationExplain air emissions, ash residue and capital cost.Why it mattersThe environmental cost of combustion.Medium
• 9CompostingExplain controlled decomposition of organic waste.Why it mattersDiverts the largest domestic waste fraction.Medium
• 10Waste hierarchyExplain reduce, reuse, recycle and dispose in order of preference.Why it mattersThe organising framework for waste strategy.Medium
• 11The circular economyExplain designing waste out of production systems.Why it mattersThe systemic alternative to linear consumption.Medium
• 12Electronic wasteExplain the growing volume and toxicity of discarded electronics.Why it mattersA rapidly rising and hazardous waste stream.Medium

Hard — Structured IB

• 13Analysing waste generation and incomeExamine how consumption patterns raise waste volume.Why it mattersExplains international differences in waste per capita.Hard
• 14Analysing barriers to recyclingExamine contamination, cost and market demand.Why it mattersExplains why recycling rates plateau.Hard
• 15Analysing waste management levelsExamine altering activity, controlling release and clean-up.Why it mattersApplies the ESS pollution management framework.Hard
• 16Analysing international waste tradeExamine export of waste to lower-income countries.Why it mattersRaises significant environmental justice concerns.Hard
• 17Analysing energy recovery from wasteExamine efficiency against emissions and infrastructure lock-in.Why it mattersDetermines whether incineration is defensible.Hard
• 18Analysing waste composition dataInterpret figures on waste stream proportions.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating waste management strategiesJudge effectiveness, cost and environmental impact.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing recycling as a waste solutionJudge material recovery against energy use and contamination.Why it mattersRequires balanced two-sided reasoning.Very Hard
• 21Evaluating the circular economyJudge its promise against practical implementation barriers.Why it mattersTests critical assessment of a popular concept.Very Hard
• 22Judging the most effective level of waste managementEvaluate prevention against disposal approaches.Why it mattersRequires prioritisation with clear justification.Very Hard
• 23Integrating waste management with resource useLink waste reduction to natural capital conservation.Why it mattersRewards a synoptic link back into Unit 7.1.Very Hard
• 24Constructing a full waste management evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Crude birth and death ratesDefine births and deaths per thousand people per year.Why it mattersThe basic measures of population change.Easy
• 2Natural increase rateCalculate the difference between birth and death rates.Why it mattersDetermines whether a population grows or shrinks.Easy
• 3Doubling timeCalculate the years needed for a population to double.Why it mattersCommunicates the pace of population growth.Easy
• 4Total fertility rateDefine average births per woman over a lifetime.Why it mattersThe key determinant of long-term population trend.Easy
• 5Replacement fertilityDefine the fertility level maintaining a stable population.Why it mattersThe benchmark for demographic stability.Easy
• 6Age-sex pyramidsInterpret diagrams of population structure.Why it mattersA guaranteed data skill in Paper 1.Easy

Medium — Applications

• 7Interpreting population pyramid shapesExplain expanding, stable and contracting structures.Why it mattersPredicts future population change and needs.Medium
• 8The demographic transition modelExplain the stages of demographic change over time.Why it mattersThe organising model of population study.Medium
• 9Stages of the demographic transitionExplain birth and death rate patterns at each stage.Why it mattersThe detail required for full marks.Medium
• 10Factors affecting fertilityExplain education, income, healthcare and culture.Why it mattersIdentifies the levers available to population policy.Medium
• 11Factors affecting mortalityExplain nutrition, sanitation, healthcare and conflict.Why it mattersExplains falling death rates during transition.Medium
• 12Population management policiesExplain pro-natalist and anti-natalist approaches.Why it mattersThe direct policy response to demographic trends.Medium

Hard — Structured IB

• 13Analysing the limitations of the demographic transition modelExamine its Eurocentric basis and assumptions.Why it mattersA guaranteed evaluation point on the model.Hard
• 14Analysing consequences of an ageing populationExamine dependency, workforce and service pressures.Why it mattersA major issue in developed economies.Hard
• 15Analysing consequences of a youthful populationExamine education, employment and service demands.Why it mattersA major issue in many developing economies.Hard
• 16Analysing the effect of population on resource useExamine consumption per capita against total numbers.Why it mattersPrevents blaming numbers alone for impact.Hard
• 17Analysing migration and population changeExamine effects on both origin and destination areas.Why it mattersAdds a third variable beyond births and deaths.Hard
• 18Analysing population dataInterpret pyramids, rates and projection figures.Why it mattersA guaranteed Paper 2 data task.Hard

Very Hard — Integrated SL

• 19Evaluating the demographic transition modelJudge explanatory value against its limitations.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing a named population management policyJudge outcomes against objectives and ethics.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating population against consumption as environmental driversJudge which contributes more to total impact.Why it mattersA contested and frequently examined debate.Very Hard
• 22Judging the reliability of population projectionsEvaluate the assumptions behind long-range forecasts.Why it mattersRequires careful handling of uncertainty.Very Hard
• 23Integrating population dynamics with resource securityLink demographic change to future resource demand.Why it mattersRewards a synoptic link back into Chapter 7.Very Hard
• 24Constructing a full population evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1UrbanisationDefine the growing proportion of people living in urban areas.Why it mattersThe dominant global settlement trend.Easy
• 2Characteristics of urban areasIdentify high density, built surfaces and concentrated demand.Why it mattersDetermines the environmental profile of cities.Easy
• 3Urban systemsDescribe cities as systems with inputs, storages and outputs.Why it mattersApplies systems thinking to human settlements.Easy
• 4Push and pull factorsIdentify the causes of rural to urban migration.Why it mattersExplains why cities grow so rapidly.Easy
• 5Urban sprawlDefine low-density expansion at the edge of a city.Why it mattersConsumes land and increases transport demand.Easy
• 6The urban heat islandDefine elevated temperatures within built-up areas.Why it mattersA direct climatic effect of urban surfaces.Easy

Medium — Applications

• 7Causes of the urban heat islandExplain absorption, waste heat and reduced vegetation.Why it mattersThe mechanism required for full marks.Medium
• 8Environmental impacts of urbanisationExplain land conversion, runoff and concentrated pollution.Why it mattersThe environmental cost of city growth.Medium
• 9Ecological footprint of citiesExplain the land area needed to sustain urban consumption.Why it mattersCities depend on resources far beyond their borders.Medium
• 10Sustainable urban planningExplain compact design, transport and green infrastructure.Why it mattersThe main response to urban environmental pressure.Medium
• 11Green infrastructureExplain parks, green roofs and urban trees.Why it mattersReduces heat, runoff and air pollution together.Medium
• 12Sustainable transport planningExplain public transport, cycling and pedestrian priority.Why it mattersTargets the largest source of urban emissions.Medium

Hard — Structured IB

• 13Analysing urban runoff and flood riskExamine surface sealing and drainage capacity.Why it mattersExplains flash flooding in expanding cities.Hard
• 14Analysing the sustainability of urban food supplyExamine transport distance and urban agriculture.Why it mattersLinks cities directly to food systems.Hard
• 15Analysing waste management in citiesExamine collection, treatment and disposal capacity.Why it mattersA major constraint in fast-growing cities.Hard
• 16Analysing informal settlementsExamine service provision and environmental exposure.Why it mattersRaises significant environmental justice concerns.Hard
• 17Analysing compact against dispersed urban formExamine land use, transport and service efficiency.Why it mattersThe central urban planning trade-off.Hard
• 18Analysing urban dataInterpret density, emissions and growth statistics.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating sustainable urban planning strategiesJudge effectiveness, cost and social acceptability.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing a named sustainable city initiativeJudge outcomes against its stated objectives.Why it mattersRewards applied use of a specific case.Very Hard
• 21Evaluating urban living against rural livingJudge per capita environmental impact of each.Why it mattersA counterintuitive and frequently examined comparison.Very Hard
• 22Judging planning priorities for a growing cityEvaluate competing demands under limited resources.Why it mattersRequires prioritisation with clear justification.Very Hard
• 23Integrating urban planning with climate adaptationLink city design to climate resilience.Why it mattersRewards a synoptic link back into Chapter 6.Very Hard
• 24Constructing a full urban systems evaluationBuild an evidence-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard

Easy — Foundations

• 1Urban air pollutionDefine contamination of city air by harmful substances.Why it mattersThe most immediate urban environmental hazard.Easy
• 2Primary pollutantsDefine pollutants emitted directly into the atmosphere.Why it mattersIncludes carbon monoxide and nitrogen oxides.Easy
• 3Secondary pollutantsDefine pollutants formed by reactions in the atmosphere.Why it mattersIncludes harmful tropospheric ozone.Easy
• 4Sources of urban air pollutionIdentify vehicles, industry, heating and construction.Why it mattersDetermines where controls must be targeted.Easy
• 5Particulate matterDefine fine airborne particles harmful to human health.Why it mattersThe pollutant most strongly linked to early death.Easy
• 6Photochemical smogDefine pollution formed by sunlight acting on emissions.Why it mattersExplains urban haze in sunny cities.Easy

Medium — Applications

• 7Formation of tropospheric ozoneExplain sunlight reacting with nitrogen oxides and hydrocarbons.Why it mattersThe mechanism behind photochemical smog.Medium
• 8Thermal inversionsExplain trapped air preventing pollutant dispersal.Why it mattersExplains severe smog episodes in valleys.Medium
• 9Health impacts of air pollutionExplain respiratory and cardiovascular consequences.Why it mattersThe main reason air quality is regulated.Medium
• 10Acid depositionDefine wet and dry deposition of acidifying pollutants.Why it mattersThe transboundary pollution case study in ESS.Medium
• 11Causes of acid depositionExplain sulfur and nitrogen oxide emissions.Why it mattersIdentifies the sources requiring control.Medium
• 12Strategies for improving urban air qualityExplain vehicle standards, fuel change and traffic control.Why it mattersThe applied management content of this topic.Medium

Hard — Structured IB

• 13Analysing impacts of acid depositionExamine effects on soils, water bodies and buildings.Why it mattersThe full range of consequences needed for marks.Hard
• 14Analysing acid deposition as transboundary pollutionExamine emissions crossing national borders.Why it mattersExplains the need for international agreement.Hard
• 15Analysing management of acid depositionExamine altering activity, controlling release and clean-up.Why it mattersApplies the ESS pollution management framework.Hard
• 16Analysing air quality monitoringExamine measurement methods and indicator pollutants.Why it mattersThe evidence base for regulation.Hard
• 17Analysing low emission zonesExamine effectiveness and equity of access charges.Why it mattersA widely used urban policy instrument.Hard
• 18Analysing air quality dataInterpret pollutant concentration measurements.Why it mattersA standard data-response task.Hard

Very Hard — Integrated SL

• 19Evaluating strategies to improve urban air qualityJudge effectiveness, cost and public acceptability.Why it mattersA guaranteed extended-response evaluation.Very Hard
• 20Assessing management responses to acid depositionJudge prevention, control and restoration approaches.Why it mattersApplies the management framework critically.Very Hard
• 21Evaluating a named urban air quality policyJudge outcomes against its stated targets.Why it mattersRewards applied use of a specific case.Very Hard
• 22Judging the equity of air pollution exposureEvaluate who suffers most from poor air quality.Why it mattersConnects pollution to environmental justice.Very Hard
• 23Integrating air quality with transport and energy policyLink pollution control to systemic change.Why it mattersThe synoptic reasoning examiners reward.Very Hard
• 24Constructing a full air pollution evaluationBuild a data-led argument with a supported conclusion.Why it mattersModels the top-band Paper 2 response.Very Hard