What does module 3.6 Sustainability and research methods cover in AQA Environmental Science?

It covers the principles of sustainability and sustainable development including ecological footprint and carrying capacity, the techniques used to monitor the environment and sample populations such as quadrats, transects and mark-release-recapture, and how to handle environmental data using statistics, correlation and judgements of reliability and validity.

What is the difference between ecological footprint and carrying capacity?

The ecological footprint is the area of productive land and sea needed to supply a population's resources and absorb its waste. Carrying capacity is the maximum population an environment can support indefinitely. If a footprint exceeds the available area, or a population exceeds carrying capacity, resource use is unsustainable.

How is mark-release-recapture used to estimate animal populations?

A sample of animals is captured, marked and released back into the population. After they mix, a second sample is captured and the proportion that are marked is used to estimate the total population, on the assumption that the marked proportion in the second sample reflects the proportion in the whole population.

Why does correlation not prove causation in environmental data?

A correlation shows that two variables change together, but this association can be caused by a third factor affecting both, or it may be coincidence. To establish that one variable causes the change in another you need controlled investigation and a plausible mechanism, not just a correlation.

What is the difference between reliability and validity?

Reliability is the repeatability of results: reliable data give similar values when the measurement is repeated, which replication improves. Validity is whether the data actually measure what they are meant to measure, which depends on controlling variables and using appropriate methods.

EnglandEnvironmental Science

AQA A-Level Environmental Science 3.6 Sustainability and research methods: a complete overview

A deep-dive AQA A-Level Environmental Science guide to module 3.6 Sustainability and research methods. Covers sustainability principles, monitoring and sampling techniques, and dealing with environmental data, with the exam patterns AQA repeats.

Generated by Claude Opus 4.816 min read3.6Updated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What module 3.6 actually demands
Sustainability principles
Monitoring and sampling
Dealing with environmental data
How module 3.6 is examined
Check your knowledge

What module 3.6 actually demands

Sustainability and research methods is the synthesis module of AQA A-Level Environmental Science. Module 3.6 pulls together the principles of sustainability that run through the whole course, and the practical and statistical skills used to monitor the environment and analyse the data it produces. The examiners test both conceptual understanding (what sustainability means) and applied skills (designing a sampling method, choosing a statistical test, judging data quality).

This guide walks through all three topics of the module, then sets out the exam patterns AQA repeats. Each topic has a matching dot-point page with practice questions; this overview ties them together.

Sustainability principles

Sustainability principles define sustainable development (meeting present needs without compromising future generations), the ecological footprint (the area needed to supply resources and absorb waste), and carrying capacity (the maximum population an environment can support indefinitely). You must distinguish renewable from non-renewable resources and explain how each can be used sustainably, harvesting renewables within their renewal rate and conserving non-renewables.

Monitoring and sampling

Monitoring and sampling techniques covers quadrats (plant abundance), transects (change along a gradient), mark-release-recapture and traps (mobile animals), and the importance of random sampling and replication. You must also know the abiotic and biotic factors that are monitored.

Dealing with environmental data

Dealing with environmental data covers presenting data, descriptive statistics (mean, range, standard deviation), choosing and using statistical tests to judge significance, the crucial distinction between correlation and causation, and the evaluation of reliability and validity.

How module 3.6 is examined

A typical AQA profile for Sustainability and research methods:

Definitions. Sustainability, ecological footprint, carrying capacity, reliability and validity.
Method design. Describing how to sample a habitat or population and how to make it reliable.
Data handling. Calculating a mean or interpreting standard deviation, and judging whether a result is significant.
Evaluation. Distinguishing correlation from causation and assessing the quality of an investigation.

Check your knowledge

A mix of definition, method and data questions covering module 3.6. Attempt them under timed conditions, then check against the solutions.

Define sustainable development. (2 marks)
Explain the difference between ecological footprint and carrying capacity. (2 marks)
Describe how mark-release-recapture estimates an animal population. (3 marks)
Explain why quadrats should be placed at random positions. (2 marks)
State what the standard deviation tells you about a set of data. (2 marks)
Explain why correlation does not prove causation. (2 marks)
State what a statistical test is used to decide. (2 marks)
Explain the difference between reliability and validity. (2 marks)

Solutions

Q1: Development that meets the needs of the present without compromising future generations' ability to meet their own needs.
Q2: The ecological footprint is the area a population needs to supply resources and absorb waste; the carrying capacity is the maximum population an environment can support indefinitely.
Q3: Capture, mark and release a sample; later take a second sample; the proportion marked in the second sample is used to estimate the total population.
Q4: Random placement avoids bias, so the sample is representative of the whole habitat rather than chosen where organisms appear most abundant.
Q5: It shows how spread out the values are around the mean: a small standard deviation means tightly clustered data, a large one means widely spread data.
Q6: The two variables may both be affected by a third factor, or the link may be chance; cause requires controlled investigation and a mechanism.
Q7: Whether a difference or relationship in the data is significant or could be due to chance.
Q8: Reliability is repeatability (similar values when repeated); validity is whether the data measure what they are meant to measure under controlled conditions.

Sources & how we know this

AQA A-level Environmental Science (7447) specification — AQA (2017)