ECOSYSTTEM.pptx for class 12 biology, 2024

Ecosystem

1. ECOSYSTEM – STRUCTURE AND FUNCTION -

2. What is ecosystem An ecosystem is a functional unit of nature and comprises abiotic and biotic components Has biotic and abiotic components producers, consumers decomposers Air Water Soil

3. Species composition and Stratification Identification and enumeration of plant and animal species of an ecosystem gives its species composition. Vertical distribution of different species occupying different levels is called stratification. Example: Trees - top vertical strata Shrubs - second vertical strata Herbs and grasses - bottom layers

4. Components of an Ecosystem Definition of productivity Primary production - net primary productivity (NPP) gross primary productivity (GPP) respiration losses (R) (i) Productivity (ii) Decomposition (iii) Energy flow (iv) Nutrient cycling

5. rate of biomass production is called productivity Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (gm–2 ) or energy (kcal m–2 )