AQA GCSE Biology (Triple) - Paper 2: Ecology

Flashcards covering key concepts in Ecology from the AQA GCSE Biology syllabus.

Ecology

The study of interactions between organisms and their environment.

Ecosystem

A community of living organisms interacting with each other and with the non-living environment.

Abiotic factors

Non-living environmental factors such as temperature, light intensity, moisture levels.

Biotic factors

Living factors that affect organisms, such as competition, predation, food availability.

Community

All living organisms in an ecosystem.

Population

All organisms of one species in a given area.

Habitat

The natural environment where an organism lives.

Interdependence

When species in a community depend on each other for food, shelter, pollination.

Stable community

A community where species numbers and environmental factors remain relatively constant.

Structural adaptations

Physical features of an organism that enhance its survival, e.g., thick fur.

Behavioral adaptations

Actions organisms take to survive, e.g., migration.

Functional adaptations

Internal body processes that enhance survival, e.g., physiological changes.

Extremophile

Organisms adapted to live in extreme environments such as high temperature or pressure.

Levels of organization in an ecosystem

Individual → population → community → ecosystem.

Producer

An organism (usually a green plant or alga) that makes its own food using sunlight energy.

Consumer

An organism that eats other organisms; primary consumers eat producers.

Decomposer

Microorganisms such as bacteria and fungi that break down dead organisms and waste.

Carbon cycle

The process where CO₂ is absorbed by plants in photosynthesis and carbon is transferred through food chains.

Water cycle

Evaporation from oceans/lakes → condensation forming clouds → precipitation → surface runoff.

Importance of the water cycle

It provides fresh water for organisms and helps regulate Earth’s climate.

Decay process

Microorganisms break down dead organisms using enzymes, releasing nutrients back into the soil.

Factors affecting rate of decay

Temperature, oxygen availability, water availability, and number of decomposers.

Compost production

Producing compost by allowing microorganisms to decay garden and kitchen waste.

Biogas

Fuel (mainly methane) produced by anaerobic decay of organic material using microorganisms.

Biodiversity

The variety of all living organisms (species) on Earth, within ecosystems.

Importance of biodiversity

It ensures ecosystem stability by maintaining interdependence and genetic variety.

Human actions reducing biodiversity

Deforestation, pollution, overfishing, habitat destruction, and global warming.

Global warming

An increase in Earth’s average temperature caused by rising greenhouse gases (CO₂).

Consequences of global warming

Rising sea levels, habitat loss, extinction, changes in migration and species distribution.

Impact of deforestation on carbon cycle

Less photosynthesis leads to more CO₂ in the atmosphere and contributes to global warming.

Peat bogs

Wetlands that store carbon; when drained or burned, they release CO₂.

Ways to maintain biodiversity

Breeding programmes, protecting rare habitats, reforestation, reducing deforestation.

Trophic level

Each step in a food chain showing energy transfer; producers are level 1.

Energy transfer in a food chain

About 10% of energy passes to the next level, most lost as heat.

Pyramid of biomass

A diagram showing the relative mass of living material at each trophic level.

Measuring biomass

By drying organisms and measuring dry mass per area (g/m²).

Improving efficiency of food production

Reducing energy loss by limiting movement, controlling temperature, feeding high-protein foods.

Sustainable food production

Producing enough food for current needs without damaging the environment.

Methods of sustainable fishing

Controlling net size, fishing quotas, and banning overfishing.

Pollution effects

Water: eutrophication from sewage/fertiliser; Air: smoke and acid gases; Land: landfills.

Monitoring pollution levels

Using indicator species and modern sensors.

Importance of decomposers

They recycle nutrients, returning them to the soil for plant growth.

Trophic efficiency

The percentage of energy transferred from one trophic level to the next, usually around 10%.

Role of microorganisms in cycling materials

Decomposing organic matter and releasing nutrients and CO₂ back into the environment.