define the terms ecosystem and niche

Published by Patrick Mutisya · 14 days ago

Cambridge A-Level Biology 9700 – Biodiversity: Ecosystem and Niche

Biodiversity

Learning Objective

Define the terms ecosystem and niche and understand their significance in the study of biodiversity.

Key Definitions

Ecosystem

An ecosystem is a functional unit consisting of a community of living organisms (the biotic component) interacting with the non‑living (abiotic) elements of their environment. These interactions involve the flow of energy and the cycling of nutrients, creating a self‑sustaining system.

Niche

A niche describes the role or “profession” of a species within an ecosystem. It includes the range of environmental conditions the species can tolerate, the resources it uses, its behavior, and its interactions with other organisms (e.g., predation, competition, mutualism).

Comparison of Ecosystem and Niche

AspectEcosystemNiche
ScopeWhole system of biotic and abiotic componentsSpecific role of a single species within that system
ComponentsPopulations, communities, physical environment, energy flow, nutrient cyclesHabitat, resources used, activity patterns, interactions
ScaleCan range from a pond to a forest biomeTypically at the level of an individual species
DynamicChanges through succession, disturbances, and climateMay shift with evolutionary adaptation or competition

Why These Concepts Matter

  • Understanding ecosystems helps predict how energy and matter move through the biosphere.

  • Recognising niches explains species coexistence and the mechanisms that maintain biodiversity.

  • Both concepts are essential for conservation planning, habitat restoration, and managing human impacts.

Suggested diagram: A diagram showing a forest ecosystem with arrows indicating energy flow (sun → plants → herbivores → carnivores) and a side panel illustrating the niche of a specific species (e.g., a woodpecker) within that ecosystem.