Ecosystem - Notes | Class 12 | Part 1: Ecosystem- Structure and Function

14. ECOSYSTEM

An ecosystem is a functional unit of nature, where living organisms interact each other and with the physical environment.

ECOSYSTEM – STRUCTURE & FUNCTION

Types of ecosystems 

• Terrestrial ecosystem: Forest, grassland, desert etc.
• Aquatic ecosystem: Pond, lake, wetland, river & estuary.
• Man-made ecosystem: Crop fields and aquarium.

Entire biosphere is regarded as global ecosystem.

In an ecosystem, biotic and abiotic components interact and function as a unit.

Vertical distribution of different species occupying different levels is called stratification. E.g. in a forest, trees occupy top strata (layer), shrubs the second and herbs & grasses the bottom layers.

Pond (Aquatic ecosystem) 

A pond is a shallow, simple, self-sustainable water body that exhibits all basic components of an ecosystem.

• Abiotic components: Water and soil deposit.
• Climatic conditions: Solar input, cycle of temperature, day-length etc.
• Autotrophic components: Phytoplankton, some algae and the floating, submerged and marginal plants.
• Consumers (heterotrophs): Zooplankton, free swimming and bottom dwelling forms.
• Decomposers: Fungi, bacteria and flagellates.

Pond performs all the functions of an ecosystem. E.g.

• Autotrophs convert inorganic into organic material using solar radiant energy.
• Heterotrophs consume the autotrophs.
• Decomposition and mineralization of the dead matter to release them back for reuse by the autotrophs.

4 basic components of functioning of an ecosystem:

1. Productivity 
2. Decomposition
3. Energy flow 
4. Nutrient cycling 

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👇 Select Your Topic Here 👇

• Topic 1: Ecosystem- Structure and Function
• Topic 2: Productivity, Decomposition
• Topic 3: Energy Flow
• Topic 4: Ecological Pyramids
• Topic 5: Ecological Succession
• Topic 6: Nutrient Cycling, Ecosystem Services