Ecology – GCSE AQA Higher Biology revision notes

What this topic covers

Ecology has 5 subtopics:

• Adaptations, interdependence and competition
• Organisation of an ecosystem
• Biodiversity and the effect of human interaction on ecosystems
• Trophic levels in an ecosystem (biology only)
• Food production (biology only)

Ecology lessons by subtopic

36 lessons, grouped by subtopic.

Adaptations, interdependence and competition

• Understanding Ecosystems and Their Organisation: Learn about the different levels of organisation in ecosystems, from individual organisms to entire ecosystems, and understand what makes an ecosystem function through the interaction of living and non-living components.
• Competition and Survival in Communities: Explore how organisms compete for resources in their habitats, including what plants and animals compete for, and how organisms are adapted to survive in their specific environments.
• Interdependence and Community Stability: Discover the importance of interdependence in communities, how species depend on each other, and what makes a community stable with balanced populations.
• Types of Adaptations: Explore how organisms are adapted to survive in their environments through structural, behavioural and functional adaptations. Learn to identify and explain different types of adaptations using examples from various habitats.
• Extremophiles and Extreme Environments: Discover organisms that live in extreme conditions and understand how extremophiles like deep sea vent bacteria have special adaptations to survive in environments with extreme temperature, pressure or salt concentration.
• Living Factors Affecting Communities: Explore how biotic (living) factors impact communities, including food availability, predators, pathogens, and competition between species.
• Analyzing Changes in Communities: Learn to explain how changes in biotic factors affect communities using data and real-world examples.
• Physical Abiotic Factors in Ecosystems: Explore how physical environmental factors including light intensity, temperature, moisture levels, wind intensity and direction affect communities of organisms. Learn to identify these key abiotic factors and understand their basic effects on living organisms.

Organisation of an ecosystem

• Environmental Factors Affecting Ecosystems: Explore how key environmental factors including temperature, water availability, and atmospheric gas composition can impact ecosystems and species distribution.
• Evaluating Environmental Change Impact: Learn to evaluate how seasonal, geographic, and human-caused environmental changes affect species distribution in ecosystems, and practice analyzing given data and scenarios.
• Working with ecological data: Learn how to calculate means, understand mode and median, and create appropriate graphs for ecological studies.
• Producers and feeding relationships: Explore how photosynthetic organisms produce biomass and understand food chains from producers to consumers.
• Studying ecosystems and predator-prey relationships: Learn about ecological sampling methods using transects and quadrats, and understand predator-prey cycles in stable communities.
• Factors Affecting Decomposition and Rate Calculations: Explore how temperature, water, and oxygen availability affect the rate of biological decay. Learn to calculate rates of decomposition and translate data between numerical and graphical forms.
• Practical Applications of Decomposition: Investigate how gardeners and farmers optimize decomposition conditions for composting and explore anaerobic decay processes that produce methane in biogas generators.
• Material cycling in ecosystems: Learn how materials cycle through abiotic and biotic components of ecosystems, understanding the importance of recycling materials to provide building blocks for future organisms.

Biodiversity and the effect of human interaction on ecosystems

• Human Impacts on Biodiversity: Explore how human activities can both positively and negatively affect biodiversity in ecosystems, understanding the range of impacts humans have on the natural world.
• Conservation Programmes and Habitat Protection: Learn about conservation efforts including breeding programmes for endangered species, protection of rare habitats, and the importance of field margins and hedgerows in agriculture.
• Global and Local Environmental Solutions: Examine government initiatives to reduce deforestation and carbon emissions, plus the role of recycling in maintaining biodiversity and reducing environmental impact.
• What is Biodiversity and Why Does it Matter?: Explore the definition of biodiversity and understand how it provides stability to ecosystems by reducing species dependence on one another.
• Human Impact on Biodiversity: Investigate how human activities are reducing biodiversity and why maintaining biodiversity is crucial for the future of our species.
• How Human Activities Reduce Land for Wildlife: Explore how building, quarrying, farming and waste dumping reduce available land for plants and animals, and examine the specific impact of peat bog destruction on biodiversity and carbon release.
• Understanding Global Warming and Its Biological Impact: Explore how increasing levels of carbon dioxide and methane in the atmosphere contribute to global warming, and examine the various biological consequences this has on living organisms and ecosystems worldwide.
• Types and Sources of Pollution: Explore the different types of pollution that occur in water, air, and on land, examining specific sources like sewage, fertilisers, toxic chemicals, smoke, acidic gases, and landfill waste.

Trophic levels in an ecosystem (biology only)

• Pyramids of Biomass and Energy Transfer: Learn about pyramids of biomass and how energy is transferred from producers to consumers, including the 1% rule for photosynthesis and the 10% rule for biomass transfer between trophic levels.
• Why Biomass is Lost Between Trophic Levels: Explore the reasons for biomass loss between trophic levels, including waste products, respiration, and the role of glucose metabolism in energy loss.
• Calculating Biomass Transfer Efficiency: Learn how to calculate the efficiency of biomass transfers between trophic levels and explain how this affects the number of organisms at each level in food chains.
• Understanding Pyramids of Biomass: Learn what pyramids of biomass are, how they represent the relative amount of biomass at each trophic level in a food chain, and practice constructing accurate pyramids from data. Students will understand that trophic level 1 forms the base of the pyramid and develop skills in interpreting and drawing biomass pyramids from given information.
• Understanding Trophic Levels in Ecosystems: Learn what trophic levels are and how organisms are classified into different levels based on their feeding relationships, from producers through to apex predators.
• The Role of Decomposers in Ecosystems: Explore how decomposers break down dead organic matter and their crucial role in nutrient cycling within ecosystems.

Food production (biology only)

• What is Food Security and Its Challenges: Students learn what food security means and explore how population growth, changing diets, and economic factors threaten global food security.
• Biological and Environmental Threats to Food Security: Students investigate how new pests and pathogens, environmental changes, and conflicts affect food production and availability around the world.
• Declining Fish Stocks and Their Conservation: Explore why fish stocks in the oceans are declining and understand the importance of maintaining fish populations at sustainable levels to prevent species disappearance. Examine how conservation methods like controlling net sizes and fishing quotas help maintain fish stocks at sustainable levels.
• Biotechnology Solutions for Food Production: Explore how biotechnology and genetic modification can help meet the demands of a growing human population, including the production of mycoprotein from Fusarium fungus and the use of genetically modified bacteria to produce human insulin.
• GM Crops and Improved Nutrition: Investigate how genetically modified crops can provide more food and improved nutritional value, with a focus on golden rice as an example of enhanced food production.
• Improving Food Production Efficiency in Farming: Learn how farmers can improve the efficiency of food production by controlling energy transfer in farm animals. Explore methods including restricting animal movement, controlling environmental temperature, and using high protein feeds to increase growth rates.

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More in this course

Go back to the full GCSE AQA Higher Biology topic list, or practise this topic with past-paper questions.