Ecosystem β Composition, Structure, Function & Productivity YouTube Lecture Handouts for NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc. 2023
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Ecosystem - Biotic & Abiotic (Components) , 3 Types & 2 Functions
Ecosystem
- Self-regulated & self-sustaining
- Structural and Functional unit of nature includes living beings and environment
- Interact and exchange material
- Open System β input of energy and matter
- Result in productivity
Types of Ecosystem
Homeostasis/Biological Equilibrium
Functional balance which is not static and fluctuates within limits
Controls
- Carrying Capacity
- Recycling Waste
- Self-Regulation
- Feedback System
π Components of Ecosystem
π Biotic β food contains energy for body building, growth and functions
- Producers (Autotrophs)
- Consumers (Heterotrophs)
- Decomposers (Reducers)
Abiotic β non-living factors
- Temperature
- Light
- Wind
- Humidity β epiphytes that grow
- Precipitation
- Water β xerophytes & hydrophytes
- Background β Chameleon (change color) ; praying mantis & frog are green
- Gases
- Soil β water retention, aeration & minerals
- pH β acidic (Euglena & flagellates) or basic (calcareous shells)
- Relief β north & south faces of hill
- Mineral Elements
Structure
- Species Composition β identify and enumerate plants and animals
- Stratification β vertical layers
- Trophic Levels
- π Standing Crop β living biomass in unit area (dry weight is preferred as is independent of moisture differences)
- π Standing State β inorganic nutrients in ecosystem (non-living)
π Ecosystem Functions
- Productivity
- Decomposition
- Energy Flow
- Nutrient Cycling
Productivity
Rate of synthesis of energy containing biomass by any trophic level per unit area in unit time
Measured as
Measured as
π Primary Productivity β energy accumulation in green plants per unit area over time
Secondary Productivity β Rate of re-synthesis of material by consumers
Respiration loss is 20% for autotrophs, 30% for herbivores and 60% for carnivores
Maximum productivity β tropical rainforest
Minimum productivity β desert or Arctic regions
Order of productivity:
Tropical Rainforest > Tropical Deciduous > Temperate Deciduous > Temperate Coniferous > Savannah > Temperate Grassland > Scrub
Factors Affecting Productivity
- Solar radiation - maximum in tropics and so photosynthesis and NPP highest in tropics
- Temperature β temperate forest have lesser productivity due to cold climate
- Moisture
- Nutrients
- Photosynthetic Efficiency
Decomposition
Detritus
- Above Ground β litter (plant driven) , dried plants
- Below Ground β dead roots, underground dead animals
π Process
- Fragmentation of Detritus (earthworm as farmerΥs friends)
- Catabolism
- Leaching β soluble substances are subject to leaching
π Products formed
- Humus by humification β humus is dark colored organically rich in lignin and cellulose
- Inorganic nutrients by mineralization β both non mineral () & mineral () from organic matter
Factors Affecting Decomposition
- Temperature
- Moisture β excess moisture impedes decomposition due to anaerobiosis
- pH β alkaline soils are rich in detrivores and acidic nature decreases detrivores
- Composition β chitin and lignin are slow to decompose
- Aerobiosis β aerobic conditions are required
β Mayank