Ecology and Ecosystems

Ecology is the study of the interactions between organisms and their environment. At A-Level, you need to understand how energy flows through ecosystems, how nutrients are recycled, how populations change over time, and how human activities affect ecological systems. This topic draws together concepts from photosynthesis and respiration and applies them to the scale of whole communities and ecosystems.

Key Definition: An ecosystem is a community of living organisms (biotic components) interacting with each other and with their non-living (abiotic) environment, within a defined area. It includes all the energy flows and nutrient cycles that sustain it.

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Key Ecological Terms

Before exploring ecological concepts in depth, it is essential to define the core terminology precisely, as examiners frequently test whether students can distinguish between these terms.