AQA Biology Organisation of an ecosystem

Choose a revision tool

Start revising Organisation of an ecosystem

Quick active recall practice

Quick multiple-choice practice

Mixed practice and exam-style prompts

Structured topic notes

Timed score-based practice

Full topic guide

Syllabus checklist

45 objective pages available

Levels of organisation16 objectives

Explain that photosynthetic organisms are producers of biomass for life on Earth.
Describe feeding relationships in a community using food chains.
Identify producers as organisms, usually green plants or algae, that make glucose by photosynthesis.
Describe primary, secondary, and tertiary consumers in food chains.
Define predators as animals that kill and eat prey.
Explain why predator and prey numbers can rise and fall in cycles in a stable community.
Interpret graphs used to model predator-prey cycles.
Describe how quadrats can be used to estimate abundance of a species in a habitat.
Describe how transects can be used to investigate how distribution changes across a habitat.
Explain why ecologists use sampling methods to estimate distribution and abundance.
Understand mean, mode, and median in relation to abundance data.
Calculate arithmetic means from ecological sampling data.
Plot and draw appropriate graphs for ecological data, selecting suitable axis scales.
Carry out required practical 9 by measuring population size of a common species in a habitat.
Use sampling techniques to investigate how a factor affects the distribution of a species.
Apply apparatus and technique skills for ecological sampling, including safe fieldwork and accurate measurement.

How materials are cycled12 objectives

Recall that many materials cycle through abiotic and biotic components of ecosystems.
Explain why carbon and water cycles are important to living organisms.
Explain that materials in the living world are recycled to provide building blocks for future organisms.
Describe how the carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide.
Explain how plants take in carbon dioxide during photosynthesis.
Describe the water cycle as providing fresh water for plants and animals before water drains to the seas.
Describe evaporation and precipitation as processes in the water cycle.
Explain the role of microorganisms in returning carbon to the atmosphere and mineral ions to the soil.
Interpret diagrams of the carbon cycle.
Interpret diagrams of the water cycle.
Explain processes shown in carbon cycle and water cycle diagrams.
Recall that the nitrogen cycle is not required for GCSE Biology 8461.

Decomposition (biology only)12 objectives

Explain how temperature affects the rate of decay of biological material.
Explain how water availability affects the rate of decay.
Explain how oxygen availability affects the rate of decay.
Calculate rate changes in decay of biological material.
Translate decay information between numerical and graphical forms.
Plot and draw appropriate graphs for decay data using suitable axis scales.
Explain how gardeners and farmers provide optimum conditions for rapid decay of waste biological material.
Describe compost as a natural fertiliser produced from decayed biological material.
Explain that anaerobic decay can produce methane gas.
Describe how biogas generators can produce methane as a fuel.
Carry out required practical 10 by investigating the effect of temperature on the rate of decay of fresh milk using pH change.
Apply apparatus and technique skills for required practical 10, including measurement, temperature control, and pH monitoring.

Impact of environmental change (biology only) (HT only)5 objectives

Explain that environmental changes can affect the distribution of species in ecosystems (HT only).
Evaluate effects of temperature change on species distribution using supplied information (HT only).
Evaluate effects of water availability on species distribution using supplied information (HT only).
Evaluate effects of atmospheric gas composition on species distribution using supplied information (HT only).
Distinguish seasonal, geographic, and human-caused environmental changes (HT only).

biomassphotosynthetic organismfood chainDescribeproducerIdentifytertiary consumerpredatorpreygraphmodeabundance

Levels of organisation exam tip 1: Use precise biological vocabulary when you explain how to explain that photosynthetic organisms are producers of biomass for life on Earth..
Levels of organisation exam tip 1: Use precise biological vocabulary when you explain how to describe feeding relationships in a community using food chains..

Levels of organisation common mistake 1: Answer by clearly explaining how to explain that photosynthetic organisms are producers of biomass for life on Earth..
Levels of organisation common mistake 1: Answer by clearly explaining how to describe feeding relationships in a community using food chains..

Choose a learning objective

Objectives are grouped by subtopic so students can jump straight to the exact skill they want to revise.