1. Ecosystem: A self-sustaining system of biotic (living)
and abiotic (non-living) components that interact and exchange energy and matter.
2. Trophic Levels: Each step in a food chain. T1: Producers,
T2: Primary consumers (herbivores), T3: Secondary consumers (carnivores), T4: Tertiary consumers (top
carnivores).
3. 10% Law (Lindeman): Only 10% of energy is transferred to
the next trophic level. Remaining 90% is lost as heat, respiration, and excretion.
4. Food Web: Interconnected network of many food chains.
More stable than a single chain because organisms have alternate food sources.
5. Role of Decomposers: Break down dead organic matter,
releasing nutrients back into the soil for producers. Essential for nutrient cycling.
6. Biodegradable Waste: Substances broken down by
microorganisms. Examples: Paper, vegetable peels, cotton, wood. Decompose in weeks to months.
7. Non-Biodegradable Waste: Substances NOT broken down
naturally. Examples: Plastic, glass, DDT. Persist for hundreds of years.
8. Biomagnification: Accumulation of toxic substances (like
DDT) in increasing amounts at higher trophic levels. Top predators have highest concentration.
9. Ozone Layer: O₃ in stratosphere (15-35 km). Absorbs
harmful UV rays from sun, protecting life on Earth.
10. Ozone Depletion: CFCs (chlorofluorocarbons) release Cl
atoms that break down O₃ → O₂. Results in ozone hole, more UV reaching Earth (skin cancer, cataracts).
11. Greenhouse Effect: Trapping of sun's heat by greenhouse
gases (CO₂, CH₄, N₂O). Natural effect keeps Earth warm. Enhanced by human activities → Global Warming.
12. Global Warming Effects: Rising sea levels (ice melting),
extreme weather, coral bleaching, ecosystem disruption.
