Last reviewed 4 Nov 2026 · 2 min read
1. Definition and scope
DefinitionEcosystem
A functional unit of nature in which living organisms (biotic) interact with each other and with their physical environment (abiotic), exchanging energy and matter. The term was coined by A. G. Tansley (1935).
- Ecology — the study of relationships between organisms and their environment (term by Ernst Haeckel, 1866).
- Levels of organisation: organism → population → community → ecosystem → biome → biosphere.
- Scope / importance — ecosystems provide food, water, clean air, climate regulation, soil fertility and recreation; understanding them is the basis of resource management, pollution control and EIA.
2. Structure
| Component | Parts |
|---|---|
| Abiotic | Inorganic (C, N, P, water, CO₂, O₂), organic (proteins, carbohydrates, humus), climatic factors (light, temperature, rainfall, humidity, wind), soil and topography |
| Biotic | Producers (autotrophs) — green plants, algae, phytoplankton; consumers (heterotrophs) — herbivores (primary), carnivores (secondary, tertiary), omnivores; decomposers — bacteria and fungi that break dead matter into nutrients |
- Species composition and stratification (vertical layering — e.g. canopy, shrubs, herbs in a forest) describe the community's structure.