Renewable Resources: Resources that can be replenished naturally over time.

• Examples: Sunlight, wind, water, forests, soil
• These are infinite or can be regenerated if properly managed

Non-Renewable Resources: Resources that cannot be regenerated once used up.

• Examples: Coal, petroleum, natural gas, minerals
• Formed over millions of years; once exhausted, cannot be replaced

Key Difference: Renewable resources are sustainable; non-renewable resources will eventually run out and cause environmental damage when over-exploited.

Definition: Deforestation is the large-scale removal of trees and forests for other land uses.

Causes:

• Agricultural expansion – forests cleared for farming
• Timber extraction – commercial logging
• Mining activities – forest land cleared for mines
• Construction of dams, roads, and urban areas
• Fuel wood collection by local communities

Effects:

• Loss of biodiversity – animals and plants lose habitat
• Soil erosion – tree roots hold soil; without them, soil washes away
• Climate change – forests absorb CO₂; deforestation releases it
• Floods and drought – trees regulate water cycle
• Desertification – land becomes barren

Control Measures:

• Afforestation – planting new trees
• Reforestation – replanting in deforested areas
• Strict legal protection of forests
• Use of alternative fuels instead of firewood
• Promoting sustainable agriculture (agroforestry)

Problems:

• Over-utilization: Excess withdrawal of surface and groundwater for agriculture, industry
• Floods: Caused by heavy rain, deforestation, and poor drainage
• Drought: Shortage of water due to low rainfall or over-extraction
• Water Conflicts: Disputes between states/countries over shared rivers
• Dam problems: Dams displace communities, affect ecosystems downstream

Conservation Methods:

• Rainwater harvesting
• Drip irrigation in agriculture
• Recharge of groundwater
• Treating and reusing wastewater

Conventional (Non-Renewable) Energy Sources:

• Coal, Petroleum, Natural Gas – fossil fuels
• Nuclear energy – uses uranium
• Cause pollution and greenhouse gas emissions
• Finite resources – will run out

Non-Conventional (Renewable) Energy Sources:

• Solar Energy: From sunlight using solar panels – clean and abundant
• Wind Energy: Wind turbines convert wind to electricity
• Hydropower: Energy from flowing water in rivers/dams
• Geothermal Energy: Heat from inside the Earth
• Biomass Energy: From organic waste, wood, crop residue
• Tidal Energy: From ocean tides

Why Alternative Energy?

• Fossil fuels are depleting fast
• Growing energy demand worldwide
• Need to reduce carbon emissions and climate change

Land Degradation: Decline in quality and productivity of land due to human activities.

• Causes: Deforestation, overgrazing, mining, improper farming

Soil Erosion: Removal of topsoil by wind or water.

• Types: Wind erosion (arid regions), Water erosion (rain/rivers)
• Effects: Loss of fertile land, sedimentation in rivers

Desertification: Fertile land turns into desert due to drought, deforestation, and overuse.

• India's problem: Rajasthan, parts of Maharashtra and Gujarat affected
• Prevention: Shelter belts of trees, proper irrigation, reducing overgrazing

Definition: An ecosystem is a community of living organisms (biotic) interacting with their non-living environment (abiotic) as a system.

Structure of Ecosystem:

• Abiotic Components: Sunlight, water, soil, temperature, minerals
• Biotic Components:
  • Producers – plants that make food through photosynthesis
  • Consumers – animals (Primary, Secondary, Tertiary)
  • Decomposers – bacteria and fungi that break down dead matter

Functions of Ecosystem:

• Energy flow – from sun → producers → consumers → decomposers
• Nutrient cycling – nutrients recycled through biogeochemical cycles
• Productivity – primary production by plants; secondary by animals
• Decomposition – breaking down dead organic matter
• Regulation of climate, water cycle, gas composition

Types: Forest, Grassland, Desert, Aquatic (pond, lake, river, ocean)

Definition: Energy flows in one direction through the ecosystem – from Sun → Producers → Consumers.

Trophic Levels:

• T1 – Producers: Plants absorb solar energy (photosynthesis)
• T2 – Primary Consumers: Herbivores (e.g., grasshopper, rabbit)
• T3 – Secondary Consumers: Carnivores that eat herbivores (e.g., frog, fox)
• T4 – Tertiary Consumers: Top predators (e.g., eagle, tiger)
• Decomposers: Break down dead matter, return nutrients to soil

10% Law (Lindeman's Law):

• Only 10% of energy is transferred from one trophic level to the next
• 90% is lost as heat during respiration and other activities
• Example: 1000 kcal in plants → 100 kcal in herbivores → 10 kcal in carnivores

Importance: Explains why food chains are short (usually 4–5 levels) and why fewer top predators exist in nature.

Food Chain: A linear sequence of organisms where each is eaten by the next.

• Example: Grass → Grasshopper → Frog → Snake → Eagle
• Types: Grazing food chain (starts with plants), Detritus food chain (starts with dead matter)

Food Web: An interconnected network of many food chains in an ecosystem.

• More realistic than food chain
• Provides stability – if one species disappears, others can compensate
• Example: In a forest, a deer is eaten by tigers AND leopards AND wolves

Key Difference: Food chain is simple and linear; food web is complex and shows real relationships in nature.

Definition: A graphical representation of the number, biomass, or energy at each trophic level.

Types:

• Pyramid of Numbers: Shows number of organisms at each level. Usually upright (many plants, few predators). Can be inverted (e.g., one tree supporting many insects).
• Pyramid of Biomass: Shows total mass of living material at each level. Usually upright in terrestrial ecosystems. Inverted in aquatic ecosystems.
• Pyramid of Energy: Shows energy at each trophic level. Always upright – energy always decreases as you go up. Most accurate pyramid.

Definition: The gradual and orderly change in the composition of species in an ecosystem over time.

Types:

• Primary Succession: Begins on bare, lifeless land (e.g., new volcanic island, bare rock). Pioneer species (lichens, mosses) first colonize.
• Secondary Succession: Occurs where ecosystem was disturbed but soil remains (e.g., after a fire or flood). Faster than primary succession.

Stages: Pioneer community → Intermediate communities → Climax community (stable, final stage)
Importance: Helps restore degraded ecosystems; explains how forests develop over time.

Definition: Biodiversity is the variety of life on Earth – including all plants, animals, microorganisms, and the ecosystems they form.

Levels of Biodiversity:

• Genetic Diversity: Variation in genes within a species (e.g., different rice varieties)
• Species Diversity: Variety of different species in an area (e.g., a rainforest has thousands of species)
• Ecosystem Diversity: Variety of ecosystems – forests, grasslands, wetlands, deserts, oceans

Values of Biodiversity:

• Direct Values: Food, medicine, timber, fiber – economic uses
• Indirect Values: Ecosystem services – clean air/water, soil fertility, climate regulation
• Option Values: Future potential for medicines and discoveries
• Existence Values: Ethical and aesthetic – every species has right to exist

India's Biodiversity: One of 17 mega-diverse countries. Rich in species of plants, animals, and microbes.

Main Threats:

• Habitat Loss: Most serious threat – forests cleared for agriculture, urban growth, mining
• Poaching of Wildlife: Illegal hunting for skin, bones, horns, tusks (tiger, elephant, rhino)
• Man-Wildlife Conflict: As forests shrink, animals enter human areas – both sides harmed
• Invasive Species: Non-native species introduced and destroy native species
• Pollution: Air, water, and soil pollution kills species
• Climate Change: Temperature rise, changing rainfall – species cannot adapt fast enough
• Over-exploitation: Over-fishing, over-harvesting beyond sustainable limits

IUCN Categories of Threat: Extinct → Extinct in Wild → Critically Endangered → Endangered → Vulnerable → Near Threatened → Least Concern

In-situ Conservation (On-site): Protecting species in their natural habitats.

• National Parks: Protected areas – no human activity. E.g., Jim Corbett, Kaziranga
• Wildlife Sanctuaries: Some human activities allowed. E.g., Mudumalai, Chilika
• Biosphere Reserves: Large areas protecting ecosystems, culture, research. E.g., Nilgiris, Sundarbans
• Sacred Groves: Traditional forest patches protected by local communities

Ex-situ Conservation (Off-site): Protecting species outside their natural habitats.

• Zoological Parks (Zoos): Animals maintained for breeding and education
• Botanical Gardens: Plants preserved for research
• Seed Banks: Seeds stored at low temperature (e.g., National Bureau of Plant Genetic Resources)
• Cryopreservation: Preserving genetic material at very low temperatures
• Captive Breeding: Breeding endangered animals in controlled environments

Conservation Schemes in India:

• Project Tiger (1973) – to protect tigers
• Project Elephant (1992) – to protect elephants
• Gir Lion Sanctuary – to protect Asiatic lions
• Sea Turtle Conservation – along coast of Odisha, Tamil Nadu

Definition: A biodiversity hotspot is a region with exceptionally high species richness AND under severe threat (at least 70% of original habitat lost).

India has 4 Biodiversity Hotspots:

• Western Ghats: Runs along west coast of India; extremely rich in endemic species of plants, amphibians, reptiles. UNESCO World Heritage Site.
• Himalayas: Snow leopard, red panda, alpine plants; huge altitudinal diversity
• Indo-Burma Region: Northeast India; rich in mammals, birds, freshwater fish
• Sundaland (Nicobar Islands): Part of the larger Sundaland hotspot; unique island species

Global: There are 36 biodiversity hotspots worldwide, covering only 2.3% of Earth's surface but supporting more than 50% of plant species and 43% of vertebrate species.

Definition: Presence of harmful substances in the atmosphere beyond acceptable limits.

Causes:

• Burning of fossil fuels (vehicles, power plants) – CO, SO₂, NO₂
• Industrial emissions – factories release toxic gases
• Agricultural activities – burning of crop residue, pesticide sprays
• Deforestation – less CO₂ absorption
• Natural: Volcanic eruptions, forest fires

Effects:

• Respiratory diseases – asthma, bronchitis, lung cancer
• Acid rain – damages buildings, crops, aquatic life
• Global warming and climate change
• Ozone layer depletion – UV radiation increases
• Smog – reduced visibility, eye irritation

Control Measures:

• Use of CNG, electric vehicles
• Catalytic converters in vehicles
• Industrial scrubbers and filters
• Shifting to renewable energy
• Afforestation
• Air Quality Index (AQI) monitoring

Definition: Contamination of water bodies (rivers, lakes, groundwater) making it unfit for use.

Causes:

• Industrial effluents – heavy metals, chemicals
• Agricultural runoff – pesticides, fertilizers, causing eutrophication
• Sewage and domestic waste – pathogens, BOD increase
• Oil spills – harm marine life
• Dumping of garbage in water bodies

Effects:

• Waterborne diseases – cholera, typhoid, dysentery
• Death of aquatic life
• Eutrophication – excess algae growth, oxygen depletion
• Bioaccumulation – toxins accumulate in food chain

Control: Sewage treatment plants, industrial waste treatment, reducing chemical fertilizers, strict laws.

Greenhouse Effect: Natural process where greenhouse gases (CO₂, CH₄, N₂O, water vapor) trap heat in the atmosphere. Without it, Earth would be -18°C. But excess greenhouse gases cause Global Warming.

Causes of Global Warming:

• Burning fossil fuels – main source of CO₂
• Deforestation – less CO₂ absorption
• Industrial activities – release of CH₄, N₂O
• Agricultural practices – paddy fields, cattle (methane)
• Landfills – decomposing waste releases methane

Effects of Climate Change:

• Rise in sea levels – melting glaciers and polar ice
• Extreme weather events – more frequent floods, droughts, cyclones
• Shifts in seasons and monsoon patterns
• Loss of biodiversity – species cannot adapt
• Food and water insecurity
• Health impacts – spread of diseases

Solutions:

• Reduce fossil fuel use; shift to renewables
• International agreements: Paris Agreement (2015)
• Carbon sequestration – planting forests
• Energy efficiency in buildings, transport, industry

Ozone Layer: Found in the stratosphere (15–35 km above Earth); absorbs harmful UV radiation from the Sun.

Ozone Depletion:

• Cause: Chlorofluorocarbons (CFCs) from refrigerators, air conditioners, aerosol sprays react with ozone and destroy it
• Effect: Ozone hole over Antarctica; increased UV radiation causes skin cancer, cataracts, harm to crops and marine life
• Solution: Montreal Protocol (1987) – international agreement to ban CFCs; use of HFCs as alternatives

Acid Rain:

• Cause: SO₂ and NO₂ from industries and vehicles react with water vapor to form H₂SO₄ and HNO₃ (sulfuric and nitric acids)
• Effect: Damages buildings (marble, limestone), harms forests, kills aquatic life, acidifies soil
• Solution: Reduce SO₂ and NO₂ emissions; use scrubbers in industries; use unleaded petrol

Types of Solid Waste: Municipal (household garbage), Industrial waste, Biomedical waste, Hazardous waste, E-waste (electronics)

Methods of Management:

• Reduce: Minimize waste generation at source
• Reuse: Use items multiple times before discarding
• Recycle: Convert waste into new products (glass, paper, metals)
• Composting: Organic waste converted to manure
• Landfill: Controlled disposal in designated areas (sanitary landfill)
• Incineration: Burning at high temperature; reduces volume but may pollute air

India's Initiative: Swachh Bharat Abhiyan; Plastic Waste Management Rules; separate collection of biodegradable and non-biodegradable waste.

Definition: "Development that meets the needs of the present without compromising the ability of future generations to meet their own needs." – Brundtland Commission (1987)

Principles:

• Use resources wisely – do not over-exploit
• Economic growth must go with environmental protection
• Social equity – benefits must reach all communities
• Intergenerational equity – preserve resources for future generations

Examples:

• Solar and wind energy instead of coal
• Organic farming instead of heavy pesticide use
• Green buildings – energy-efficient construction
• UN SDGs (Sustainable Development Goals – 17 goals by 2030)

Definition: The organization and management of resources and responsibilities to deal with all humanitarian aspects of emergencies.

Types of Disasters:

• Floods: Caused by excess rainfall, river overflow; affects crops, property, lives
• Earthquakes: Caused by movement of tectonic plates; measured on Richter scale
• Cyclones: Tropical storms with high wind speed; common on India's east coast
• Landslides: Slope failure due to heavy rain, earthquakes, deforestation; common in Himalayas and Western Ghats

Disaster Management Phases:

• Mitigation: Reduce risks before disaster (building codes, early warning systems)
• Preparedness: Training, stockpiling supplies, evacuation plans
• Response: Emergency rescue operations, relief, medical aid
• Recovery: Rebuilding affected areas, rehabilitation of people

India's Initiatives:

• National Disaster Management Authority (NDMA) – set up after 2004 tsunami
• State Disaster Response Force (SDRF)
• Disaster Management Act, 2005
• Early warning systems for cyclones (IMD)

1. Environment Protection Act, 1986:

• Passed after Bhopal Gas Tragedy (1984)
• Umbrella legislation – empowers government to protect environment
• Sets standards for air, water, soil quality
• Provides for penalties for violations

2. Air (Prevention and Control of Pollution) Act, 1981:

• Controls air pollution from industries and vehicles
• Established Central and State Pollution Control Boards (CPCB/SPCB)

3. Water (Prevention and Control of Pollution) Act, 1974:

• First major environmental law in India
• Controls discharge of pollutants into water bodies
• Established Pollution Control Boards

4. Wildlife Protection Act, 1972:

• Protects wild animals and plants
• Bans hunting and trade of protected species
• Provides for National Parks, Sanctuaries, and Tiger Reserves
• CITES – international treaty under this framework

5. Forest Conservation Act, 1980:

• Prevents diversion of forest land for non-forest purposes
• Central government approval needed to use forest land

1. Chipko Movement (1973):

• Location: Uttarakhand (then Uttar Pradesh), Himalayas
• People (mainly women) hugged trees to prevent logging
• Leader: Sunderlal Bahuguna, Gaura Devi
• Result: Ban on felling trees in Himalayan forests; inspired global tree-hugging protests

2. Silent Valley Movement (1973–1985):

• Location: Kerala
• Protest against construction of a hydroelectric dam in Silent Valley rainforest
• Saved the last undisturbed tropical rainforest in India
• Result: Silent Valley National Park established (1985)

3. Bishnois of Rajasthan:

• A community with 500-year-old tradition of protecting nature
• Amrita Devi Bishnoi led villagers who sacrificed lives to protect Khejri trees (1730 AD) – the original tree-huggers
• Inspired the Chipko movement

Environmental Ethics: A branch of ethics that studies the moral relationship between humans and the natural environment.

Key Principles:

• Anthropocentrism: Humans are the most important species; nature has value only for humans
• Biocentrism: All living things have equal value and right to exist
• Ecocentrism: Entire ecosystems have value, not just individual species
• Intergenerational Responsibility: We must protect the environment for future generations

Environmental Communication and Public Awareness:

• Education at school and college level (EVS as compulsory subject – Supreme Court order)
• Media campaigns, documentaries, NGOs
• World Environment Day (June 5), Earth Day (April 22)
• Community participation in conservation programs