Golden Key Points – CHAPTER 12- ECOSYSTEM

Golden Key Points

1. Ecosystem Overview:

   • Ecosystems are functional units of nature where living organisms interact with each other and their physical environment.
   • They vary in size and can be terrestrial (land-based) or aquatic (water-based).
   • Man-made environments like crop fields and aquariums are also considered ecosystems.

2. Structure and Function of Ecosystems:

   • Ecosystem structure includes biotic (living) and abiotic (non-living) components interacting with each other.
   • Functions include productivity, energy flow, decomposition, and nutrient cycling.
   • Energy flows through food chains/webs, starting with producers and moving to consumers and decomposers.

3. Productivity:

   • Primary production is the creation of biomass by plants during photosynthesis.
   • Gross primary productivity (GPP) is total biomass production, while net primary productivity (NPP) is GPP minus energy used by plants.
   • Productivity varies based on plant species, environmental factors, and ecosystem type.

4. Decomposition:

   • Decomposers break down complex organic matter into simpler inorganic substances.
   • Detritus is the raw material for decomposition, and the process involves fragmentation, leaching, catabolism, humification, and mineralization.
   • Decomposition is influenced by oxygen availability, chemical composition, and climatic factors.

5. Energy Flow:

   • Energy flows unidirectionally from the sun to producers, then to consumers, and finally to decomposers.
   • Trophic levels represent functional levels in the food chain, with energy decreasing at each level.
   • Grazing food chains and detritus food chains depict different pathways of energy flow in ecosystems.

6. Ecological Pyramids:

   • Represent relationships between organisms at different trophic levels using pyramids of number, biomass, and energy.
   • Trophic levels are based on functional roles rather than specific species.
   • Upright pyramids show producers > herbivores > carnivores, while inverted pyramids are exceptions due to specific ecosystem conditions.