This chapter explores the environment, including its components, interaction among organisms, and our impact on ecological balance.
Our Environment – Formula & Equation Sheet
Essential formulas and equations from Science, tailored for Class X in Science.
This one-pager compiles key formulas and equations from the 'Our Environment' chapter of Science. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
Energy Flow in Ecosystem: 10% Rule
Only about 10% of the energy is transferred from one trophic level to the next. The rest is lost as heat or used in metabolic processes. This explains why food chains rarely exceed four or five trophic levels.
Biological Magnification
The increase in concentration of harmful chemicals like pesticides at successive trophic levels. For example, DDT concentration increases from water to fish to birds, affecting their health.
Ozone Formation: O₂ + UV → 2O; O + O₂ → O₃
UV radiation splits oxygen molecules (O₂) into single oxygen atoms (O), which then combine with O₂ to form ozone (O₃). This layer protects Earth from harmful UV rays.
CFCs Effect on Ozone: Cl + O₃ → ClO + O₂
Chlorofluorocarbons (CFCs) release chlorine atoms (Cl) that destroy ozone (O₃) by converting it into oxygen (O₂), leading to ozone layer depletion.
Biodegradable Waste Decomposition
Organic waste like vegetable peels decomposes into simpler substances by microorganisms, returning nutrients to the soil, essential for plant growth.
Non-Biodegradable Waste Persistence
Materials like plastics do not decompose easily, persisting in the environment for hundreds of years, causing pollution and harming wildlife.
Food Chain Length Limitation
Due to the 10% energy transfer rule, ecosystems rarely support more than 4-5 trophic levels, limiting the length of food chains.
Ecosystem Balance Equation
Producers + Consumers + Decomposers + Abiotic factors = Stable Ecosystem. Disruption in any component can lead to ecological imbalance.
Solar Energy Utilization: 1% by Plants
Only about 1% of the solar energy falling on leaves is converted into chemical energy through photosynthesis, forming the base of the food chain.
Waste Generation per Capita
Calculated as Total Waste Generated / Population. Helps in planning waste management strategies for reducing environmental impact.
Equations
Photosynthesis: 6CO₂ + 6H₂O + Light → C₆H₁₂O₆ + 6O₂
Plants convert carbon dioxide and water into glucose and oxygen using sunlight, forming the basis of the food chain.
Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
Organisms break down glucose to release energy, with carbon dioxide and water as byproducts, completing the carbon cycle.
Decomposition: Organic Matter → CO₂ + H₂O + Nutrients
Decomposers break down dead organisms, releasing carbon dioxide, water, and nutrients back into the ecosystem.
Ozone Depletion: CFCl₃ + UV → Cl + CFCl₂; Cl + O₃ → ClO + O₂
CFCs release chlorine under UV light, which then destroys ozone molecules, reducing the ozone layer's effectiveness.
Energy Transfer Efficiency: (Energy at Trophic Level n / Energy at Trophic Level n-1) × 100 ≈ 10%
Shows the efficiency of energy transfer between trophic levels, explaining the pyramid of energy in ecosystems.
Population Growth Impact: I = P × A × T
Environmental Impact (I) is a product of Population (P), Affluence (A), and Technology (T), highlighting human influence on ecosystems.
Waste Management: Reduce + Reuse + Recycle = Sustainable Environment
The 3R principle minimizes waste generation and environmental impact, promoting sustainability.
Biodiversity Index: Number of Species / Area
Measures the variety of life in a particular habitat, indicating ecosystem health and stability.
Pollution Concentration: Mass of Pollutant / Volume of Air or Water
Calculates the concentration of pollutants in the environment, assessing air or water quality.
Carbon Footprint: CO₂ Emissions per Capita
Estimates an individual's or country's contribution to global warming through CO₂ emissions, guiding reduction strategies.
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