Environment and Ecology

Subject: General Science — Technology & Environment | Topic: Environment and Ecology Exam: AP Group 2 (APPSC) | Sources: NCERT Class X, Shankar IAS Environment, Lucent's GS

Introduction

Environment and ecology is a high-yield topic — expect 2-3 questions on pollution, international agreements, ozone layer, and AP-specific environmental facts (Kolleru Lake, Coringa). The 10% energy rule and biomagnification are perennial favourites.

Ecosystem Basics

• Ecosystem: Self-sustaining unit of biotic (living) and abiotic (non-living) components.
• Biotic: Producers (plants), Consumers (animals), Decomposers (bacteria, fungi).
• Abiotic: Sunlight, temperature, water, soil, air, minerals.
• Types: Terrestrial (forest, grassland, desert) and Aquatic (freshwater, marine).

Food Chain, Food Web, and Energy Flow

• Food chain: Producer → Primary consumer → Secondary consumer → Tertiary consumer.
• Food web: Interconnected food chains.
• 10% Law (Lindeman, 1942): Only ~10% energy transfers to the next trophic level. Rest lost as heat.
• Food chains rarely exceed 4-5 levels due to energy loss.
• Biomagnification: Concentration of toxins (DDT, mercury) increases at each successive level. Top predators most affected.

Biogeochemical Cycles

Pollution

• Biodegradable: Food waste, paper, cotton. Non-biodegradable: Plastic, glass, metals.

Ozone Layer

• In stratosphere (15-35 km). Absorbs harmful UV-B/UV-C radiation.
• Depleted by CFCs, halons, methyl bromide. One Cl atom destroys ~100,000 ozone molecules.
• Ozone hole: Discovered over Antarctica (1985). Worst in Sep-Oct.
• Montreal Protocol (1987): Phase out ozone-depleting substances. Ratified by all 197 UN members. Recovery expected ~2066.

Global Warming and Climate Change

• Greenhouse gases: CO₂ (largest human contribution), CH₄ (rice paddies, livestock), N₂O (fertilizers), CFCs, water vapour.
• Global temperature risen ~1.1°C since pre-industrial era.
• Effects: rising sea levels, melting glaciers, extreme weather, coral bleaching, food insecurity.
• Acid rain: pH < 5.6. Caused by SO₂ + NOx → sulphuric/nitric acid. Damages buildings ("Marble Cancer" on Taj Mahal).

International Environmental Agreements

India's Environmental Laws

• Wildlife Protection Act (1972): National parks, sanctuaries. Schedules I-V.
• Forest Conservation Act (1980): Restricts diversion of forest land.
• Environment Protection Act (1986): Umbrella legislation.
• National Green Tribunal (NGT, 2010): Environmental dispute resolution.
• India's climate pledge: Net-zero by 2070; 50% renewable electricity by 2030; target 500 GW renewable by 2030.

Waste Management

• 3Rs: Reduce, Reuse, Recycle.
• Composting, vermicomposting (earthworms), incineration, STP (sewage treatment).
• E-waste: India 3rd largest generator. Contains toxic metals (lead, mercury).

AP-Specific Environmental Facts

Likely Exam Questions

1. The 10% energy rule was given by: Ans: Lindeman (1942)

2. The Montreal Protocol deals with: Ans: Phasing out ozone-depleting substances

3. The Paris Agreement aims to limit global warming to: Ans: Well below 2°C (preferably 1.5°C) above pre-industrial levels

4. Kolleru Lake in AP is designated as a: Ans: Ramsar site

5. Biomagnification refers to: Ans: Increasing concentration of toxins at each trophic level

6. India's target for net-zero emissions is: Ans: 2070

7. The ozone hole was first discovered over: Ans: Antarctica (1985)

8. BOD stands for: Ans: Biochemical Oxygen Demand (higher BOD = more polluted water)

9. The largest tiger reserve in India by area is: Ans: Nagarjunasagar-Srisailam (in AP's Nallamala Hills)

10. The greenhouse gas with the largest human-activity contribution is: Ans: Carbon dioxide (CO₂)