Diploma del Bachillerato Internacional · IB Diploma

Environmental Systems and Societies · HL

Papers, samples and curriculum documents for this course. · ⁨Papeles, muestras y documentos curriculares para este curso.⁩

← Exams · ⁨Exámenes⁩

Handouts, exercise sheets and slides

Shared topic documents retain their source course and topic titles. Use your chosen board’s specification for coverage, tier and exam requirements.

Handouts · ⁨Material de apoyo⁩ · AP Environmental Science · ⁨AP Ciencias Ambientales⁩ (9)

Exercise sheets · ⁨Hojas de ejercicios⁩ · AP Environmental Science · ⁨AP Ciencias Ambientales⁩ (99)

Presentation slides · ⁨Diapositivas de presentación⁩ · AP Environmental Science · ⁨AP Ciencias Ambientales⁩ (9)

Course units and learning goals · ⁨Unidades del curso y objetivos de aprendizaje⁩

These lessons teach selected course objectives. Check the remaining coverage gaps; the material is not a complete preparation programme. · ⁨Estas lecciones enseñan objetivos del curso seleccionados. Revisa los vacíos de cobertura restantes; el material no es un programa completo de preparación.⁩

Lessons · ⁨Lecciones⁩ →Vocabulary practice · ⁨Práctica de vocabulario⁩ →

1 · Foundation

An amount held within a system.
Separate physical evidence from value judgements. A stock is an amount at a time; a flow is an amount per time. Sustainability decisions require ecological, social and economic evidence and a stated scale.
Draw the system boundary before calculating a budget. Identify inflows, outflows and possible unmeasured terms. Compare stakeholder claims using the same evidence, then explain where values lead to different choices.

stock: An amount held within a system
flow: Transfer of an amount per unit time

2 · Ecology

A defined area used for sampling.
Estimate total abundance by multiplying mean density by area, with consistent units. This assumes sampled areas represent the habitat. Patchiness and too few samples widen uncertainty.
Choose coordinates with random numbers before visiting the patches. Record quadrat area and counting rules. For a transect, use fixed distances and measure a relevant abiotic variable. Do not damage habitats or sample unsafe locations.
An amount held within a system.
Separate physical evidence from value judgements. A stock is an amount at a time; a flow is an amount per time. Sustainability decisions require ecological, social and economic evidence and a stated scale.
Draw the system boundary before calculating a budget. Identify inflows, outflows and possible unmeasured terms. Compare stakeholder claims using the same evidence, then explain where values lead to different choices.

quadrat: A defined area used for sampling
population: Organisms of one species in a defined area
stock: An amount held within a system
flow: Transfer of an amount per unit time

3 · Biodiversity and conservation

The number of species recorded.
Compare surveys with similar area, effort, season and identification rules. A diversity index is meaningful only with its formula and conventions specified. Habitat fragmentation can affect movement and gene flow even when total area changes little.
Use non-destructive field sampling approved by the school. Identify organisms with a suitable key and record uncertain identifications rather than inventing species. Combine ecological evidence with stakeholder perspectives on land use.

species richness: The number of species recorded
evenness: How evenly individuals are distributed among species

4 · Water

Nutrient enrichment with ecological consequences.
Distinguish concentration from total pollutant load. Dilution can reduce concentration without removing the pollutant mass. A management plan should consider upstream causes, users and effects on other parts of the catchment.
Collect approved water-quality observations at matched sites and times. Use calibrated instruments and consistent sampling depth. Avoid contact with contaminated water and do not infer potability from clarity.

eutrophication: Nutrient enrichment with ecological consequences
pollutant load: Mass of pollutant transferred per time

5 · Land

Removal and transport of soil or rock.
Distinguish total yield from yield per area and energy input. Sustainable management must consider regeneration rates and impacts beyond the farm boundary. Different stakeholders may rank food security, biodiversity and income differently.
Compare management options using a stated functional unit and the same timescale. Use approved secondary datasets or non-destructive soil observations. Explain trade-offs instead of claiming a method has no disadvantages.

erosion: Removal and transport of soil or rock
resource: A material or service used to meet needs

6 · Atmosphere and climate change

Actions addressing causes of environmental change.
Distinguish mitigation, which addresses drivers, from adaptation, which reduces harm from impacts. A policy assessment needs evidence about effectiveness, cost, equity and uncertainty; one criterion is not the entire decision.
Compare multi-year data using consistent baselines. State the region, timescale and uncertainty. At HL, connect a management decision to law, economics and ethics rather than treating these lenses as extra definitions only.

mitigation: Actions addressing causes of environmental change
adaptation: Actions reducing harm from environmental impacts

7 · Natural resources

Removal and transport of soil or rock.
Distinguish total yield from yield per area and energy input. Sustainable management must consider regeneration rates and impacts beyond the farm boundary. Different stakeholders may rank food security, biodiversity and income differently.
Compare management options using a stated functional unit and the same timescale. Use approved secondary datasets or non-destructive soil observations. Explain trade-offs instead of claiming a method has no disadvantages.

erosion: Removal and transport of soil or rock
resource: A material or service used to meet needs

8 · Human populations and urban systems

Movement into a population.
Compare rates with a common denominator and interval. An average can hide unequal access to services. At HL, evaluate how economic incentives, legal responsibilities and ethical priorities change an urban management proposal.
Use published demographic and city-service data with dates and definitions. Protect privacy when collecting local opinions. Compare the same geographical boundary rather than mixing an urban core with a whole metropolitan region.

immigration: Movement into a population
indicator: A measure of a specified condition

HL.a · Environmental law

Implementation of rules through monitoring and consequences.
Distinguish the legal instrument from the evidence about its effect. A concentration limit can be satisfied while total pollutant load rises if flow increases. Evaluate monitoring coverage, detection probability, incentives, access to justice and effects on different groups. An observed change after a policy is compatible with an effect but also with rainfall, industrial changes or other interventions.
Use an attributed historical or clearly fictional permit and paired monitoring data. Identify the regulated activity, responsible authority, geographical boundary and date. Compare upstream/downstream and before/after observations where available, document sampling gaps, and discuss whose evidence or costs are excluded. Do not present this classroom model as advice about current local law.

enforcement: Implementation of rules through monitoring and consequences
jurisdiction: The geographical or institutional scope of an authority

HL.b · Environmental and ecological economics

A transaction effect on a third party not fully reflected in its price.
In a simplified model, marginal social cost equals marginal private cost plus marginal external cost. A pollution charge can alter incentives, but selecting a charge requires evidence and a stated objective. Monetary totals do not by themselves settle distribution, irreversibility, uncertainty or whether a service can be substituted.
Construct a transparent table with a common currency, time period and system boundary. Separate measured expenditure from estimated environmental damage. Compare at least two valuation assumptions, identify who pays and who benefits, and consider a non-monetary indicator such as habitat condition. Label these as classroom scenarios rather than forecasts.

externality · ⁨externalidad⁩: A transaction effect on a third party not fully reflected in its price
social cost: Private cost plus external cost within the stated model

HL.c · Environmental ethics

Value considered independent of usefulness to another party.
Separate descriptive claims from normative claims. A species count is evidence about the sampled community; deciding that every species has intrinsic value is a value position. Compare consequences, rights, duties and fairness across generations. A defensible argument states its values, uses accurate evidence and acknowledges competing claims rather than disguising a value choice as a calculation.
Use a fictional planning dispute or an attributed historical case. Build an argument table: stakeholder, factual claim, evidence, value principle and possible response. Include affected communities and future generations without pretending to speak for them. Use voluntary anonymous classroom positions; assess the reasoning rather than agreement with a preferred worldview.

intrinsic value: Value considered independent of usefulness to another party
environmental justice: Fair treatment in environmental burdens, benefits and decision-making

Practical · Experimental programme

A quantified limitation on a measured result.
For a product or quotient, adding fractional uncertainties is a common maximum-uncertainty approximation. For a difference, add absolute uncertainties. A nonzero intercept can reveal an offset or an incomplete model.
Show units on axes and choose a sensible scale. Plot uncertainty bars where justified, draw a best-fit line rather than joining every point, and estimate steepest and shallowest plausible gradients when the course method calls for them.

uncertainty: A quantified limitation on a measured result
systematic error: A consistent measurement bias

Preparing for this qualification · ⁨Preparación para esta cualificación⁩

ESS integrates ecological evidence with human values, systems and sustainability; it is not a generic Biology course.
HL adds environmental law, environmental/ecological economics and ethics as lenses integrated with topic evidence, alongside deeper topic coverage.
Both levels have practical work 30 h, collaborative sciences project 10 h and individual investigation 10 h. Use school-approved fieldwork and ethical social-data collection.
Written assessment and investigation details are recorded from the 2026 brief; the old SL-only 2017 brief is not the current course.
2026 assessment: SL Paper 1 is 1 h/25%, Paper 2 is 2 h/50%, investigation 25%; HL Paper 1 is 2 h/30%, Paper 2 is 2.5 h/50%, investigation 20%. Paper 1 uses an unseen case study; Paper 2 has short/data questions and structured essays. The individual investigation is a real student-formulated inquiry, 10 h and a maximum 3,000-word report.

Teaching coverage still needed · ⁨Cobertura docente aún necesaria⁩

Exact topic statements and HL extensions/lenses require the current full ESS guide; focus cases are partial.

Specifications and sample documents · ⁨Especificaciones y documentos de muestra⁩

Environmental Systems and Societies — Subject brief · 2026 ↗
First assessment: 2026

Course materials · ⁨Materiales del curso⁩

Course preparation · ⁨Preparación del curso⁩

Documents are available. Board-specific notes, assessments and interactive past-paper practice are not yet available for every course. · ⁨Los documentos están disponibles. Las notas específicas de la entidad evaluadora, las evaluaciones y la práctica interactiva deantiguos exámenes no están disponibles aún para todos los cursos.⁩

Lessons · ⁨Lecciones⁩ →