Environment, Ecology, Biodiversity, Climate Change and E-Waste Notes

Ecosystem and Ecological Concepts

Ecosystem

An ecosystem is the structural and functional unit of the environment where living organisms interact with one another and with their physical surroundings. The term was introduced by Sir Arthur George Tansley in 1935 to describe a biological community and its environment as a single interacting unit.The ecosystem should not be confused with:

• Carrying Capacity – Maximum population size that can be sustained by available resources.
• Pioneer Community – First biological community established in a newly formed habitat.
• Climax Community – Final stable stage of ecological succession.

Producers (Autotrophs)

Producers are organisms capable of synthesizing their own food through photosynthesis or chemosynthesis and form the foundation of energy flow in ecosystems.

Terrestrial Ecosystems

Primary producers are mainly:

• Trees
• Grasses

These convert solar energy into chemical energy and support herbivores and higher trophic levels.

Aquatic Ecosystems

Primary producers include:

• Phytoplankton
• Algae

These form the base of aquatic food chains and food webs.

Herbivores

Herbivores are primary consumers that feed directly on producers.Examples:

• Rabbit
• Deer

Ecosystem Services

Ecosystems provide numerous indirect benefits including:

• Water regulation
• Flood control
• Groundwater recharge
• Pollutant filtration

Wetlands such as the Sundarbans absorb excess rainfall and function as natural flood buffers.

Ecosystem Integrity

Ecosystem Integrity refers to the total health, functioning, resilience and stability of an ecosystem. It evaluates the capacity of ecosystems to maintain structure and recover from disturbances.

Biodiversity

Biodiversity

Biodiversity refers to the variety of life forms at all levels of biological organization.

Importance of Biodiversity

Biodiversity is essential for:

• Ecological balance
• Economic development
• Social values
• Environmental resilience

A biologically diverse ecosystem is better able to withstand environmental disturbances and adapt to changing conditions.

Genetic Diversity

Genetic diversity refers to variation in genes within a species.Examples:

• More than 1,000 varieties of mangoes in India.
• More than 50,000 strains of rice in India.

Species Richness

Species richness represents the total number of species present in an ecosystem.

Species Abundance

Species abundance measures the absolute population size of individual species in a community.

Species Evenness

Species evenness indicates how uniformly individuals are distributed among species.

Ecological Succession

Nudation

Nudation is the first stage of ecological succession and involves the formation of a bare area devoid of life.Causes include:

• Volcanic eruptions
• Earthquakes
• Floods
• Landslides
• Forest fires
• Diseases

Autotrophic Succession

Autotrophic succession is dominated by autotrophs and occurs where sunlight and inorganic nutrients are abundant.Example:

• Vegetation development on abandoned farmland.

Xerosere

A xerosere is ecological succession occurring in dry habitats.Stages generally progress from:

• Lichens
• Mosses
• Herbs
• Shrubs
• Forest or grassland climax community

Other Seres

Hydrosere

Succession in aquatic habitats.

Halosere

Succession in saline habitats.

Psammosere

Succession in sandy habitats such as dunes.

Evolution and Human Evolution

Evolution by Natural Selection

The theory of evolution by natural selection was independently proposed by:

• Charles Darwin
• Alfred Russel Wallace

Natural selection explains how organisms possessing advantageous traits survive and reproduce more successfully.Examples:

• Peppered moth industrial melanism
• Antibiotic resistance
• Darwin's finches

Human Evolution Timeline

Dryopithecus and Ramapithecus

• Lived about 15 million years ago.
• Displayed ape-like and human-like characteristics.

Australopithecines

• Appeared about 3–4 million years ago.
• Early upright hominids.

Homo habilis

• Appeared about 2 million years ago.
• Known as the "Handyman."

Homo erectus

• Appeared about 1.9 million years ago.
• Known as "Upright Man."

Neanderthals

• Lived between 400,000 and 40,000 years ago.

Homo sapiens

• Emerged about 300,000 years ago in Africa.

Geological Time Scale

Paleozoic Era (541–252 Million Years Ago)

Known as the Age of Invertebrates.Major developments:

• Diversification of marine life
• Emergence of trilobites
• Mollusks
• Arthropods

Mesozoic Era (252–66 Million Years Ago)

Known as the Age of Reptiles.Major developments:

• Dinosaurs dominated Earth
• Evolution of birds
• Evolution of early mammals

Cenozoic Era (66 Million Years Ago–Present)

Known as the Age of Mammals.Major developments:

• Diversification of mammals
• Rise of modern humans

Precambrian Eon

• 4.6 billion to 541 million years ago.
• Longest span in Earth's history.

Climate Change and Greenhouse Gases

Methane (CH₄)

Methane is:

• Colorless
• Odorless
• Highly flammable

Key Facts:

• Main component of natural gas.
• Contributes about 20% of global greenhouse gas emissions.
• Second most important anthropogenic greenhouse gas after CO₂.

Nitrous Oxide (N₂O)

• Known as Laughing Gas.
• Global warming potential is 298 times greater than CO₂ over 100 years.
• Atmospheric lifetime approximately 120 years.

Perfluorocarbons (PFCs)

PFCs are synthetic greenhouse gases emitted from:

• Electronics manufacturing
• Semiconductor production
• Aluminium smelting
• Magnesium production

Atmospheric lifetime:

• 800 to 50,000 years

Sulphur Hexafluoride (SF₆)

• Atmospheric lifetime about 3,200 years.
• Highest known Global Warming Potential.

Ozone Layer and Ozone Protection

Ozone Layer

Located in the stratosphere at an altitude of:

• 15–30 km

Functions as Earth's sunscreen by absorbing harmful ultraviolet radiation.

Polar Stratospheric Clouds (PSCs)

Form because of extremely cold Antarctic stratospheric temperatures.Importance:

• Provide surfaces for ozone-destroying chemical reactions.
• Convert chlorine and bromine compounds into highly reactive forms.

Ozone Depleting Gas Index (ODGI)

Developed by:

• NOAA

Purpose:

• Tracks atmospheric concentrations of ozone-depleting substances.

Montreal Protocol

Adopted:

• 1987

Entered into force:

• 1989

Objective:

• Phase-out of nearly 100 ozone-depleting substances.

Principle

Developed countries were assigned earlier phase-out schedules than developing countries.

London Amendment (1990)

Added:

• Methyl chloroform

Also mandated phase-out of:

• CFCs
• Carbon tetrachloride
• Halons

Kigali Amendment

Adopted:

• 2016

Entered into force:

• 2019

Objective:

• Phase-down of Hydrofluorocarbons (HFCs)

Indirect Benefit:

• Encourages energy-efficient cooling technologies.
• Indirectly reduces black carbon emissions.

Climate Governance and International Mechanisms

Adaptation Fund

First Commitment Period (2008–2012)

Funding Source:

• Share of proceeds from Clean Development Mechanism (CDM) projects.

CDM

Allows developed countries to earn emission credits through emission-reduction projects in developing countries.

International Emissions Trading (IET)

Established under the Kyoto Protocol.Based on:

• Cap-and-Trade principle

Example:

• European Union Emissions Trading System (EU ETS)

Beyond Oil and Gas Alliance (BOGA)

Launched:

• COP26, Glasgow (2021)

Led by:

• Costa Rica
• Denmark

Objective:

• Phase out new oil and gas exploration licences.

Major Economies Forum (MEF)

Established:

• 2009

Introduced by:

• United States

Objective:

• Climate and energy cooperation among major economies.

E-Waste Management

India's E-Waste Generation

2019

• 3.2 million metric tonnes

2025 Projection

• 5.2 million metric tonnes

Growth Rate:

• Approximately 8% annually

Global E-Waste (2019)

Total:

• 53.6 million metric tonnes

Small Equipment:

• 17.4 million metric tonnes

Large Equipment:

• 13.1 million metric tonnes

China:

• 10.1 million metric tonnes

E-Waste (Management) Rules, 2022

Extended Producer Responsibility (EPR)

Initial collection target:

• 30% of annual e-waste generation

Target increases annually.

Deposit Refund Scheme

Provides financial incentives for returning discarded electronic products for formal recycling.

CPCB Role

• Manages EPR certificates.
• Conducts compliance verification.
• Operates stakeholder registration portal.

European Union E-Waste Model

Key Features:

• Ban on hazardous e-waste exports to developing countries.
• Strong Extended Producer Responsibility framework.

Waste Management

Biomedical Waste

Incineration

Emits:

• Dioxins
• Furans
• Greenhouse gases

Impacts:

• Air pollution
• Climate change

Biomedical Waste Management Rules (Amendment), 2018

Extended applicability to:

• Veterinary hospitals
• Animal houses
• Blood banks
• Home healthcare facilities

Introduced:

• Barcoding system
• Standard Operating Procedures (SOPs)

Agricultural Solid Waste

Includes:

• Animal waste
• Crop residues
• Horticultural waste
• Agricultural medical waste

Marine Pollution

Chemical Runoff

Sources:

• Fertilizers
• Pesticides
• Industrial chemicals

Impact:

• Formation of dead zones
• Oxygen depletion
• Biodiversity loss

Oxygen-Depleting Waste

Sources:

• Untreated sewage
• Agricultural runoff
• Industrial waste

Impact:

• Dissolved oxygen depletion
• Aquatic mortality
• Hypoxic and anoxic zones

Air Pollution

Acid Rain

Impact on Forests

Acid rain damages forests by:

• Leaching essential soil nutrients

Consequences:

• Weakening of trees
• Ecosystem disruption

Quantitative Pollutants

Naturally occurring substances that become harmful at excessive concentrations.Examples:

• Ozone
• Nitrogen dioxide

Lead

Sources:

• Batteries
• Gasoline
• Industrial emissions

Effects:

• Reduced IQ
• Learning disabilities
• Behavioural disorders
• Anaemia

National Clean Air Programme (NCAP)

Launched:

• 2019

Targets by 2026:

• PM10 reduction: 40%
• PM2.5 reduction: 20%

Base Year:

• 2017

Conservation and Environmental Governance

Biosphere Reserves in India

India has:

• 18 Biosphere Reserves

These support in-situ conservation of biodiversity.

Ramsar-type Wetland Functions

Wetlands regulate:

• Floods
• Water quality
• Groundwater recharge

Other Important Facts

Bangladesh

• First country to ban thin plastic bags.
• Year: 2002

Swachh Survekshan

Conducted by:

• Ministry of Housing and Urban Affairs

Purpose:

• Assess urban cleanliness and sanitation.

Green Crackers

SAFAL

• Safe Minimal Aluminium
• Replaces aluminium with magnesium.

SWAS

• Safe Water Releaser
• Releases water vapour to suppress particulate matter.

STAR

• Safe Thermite Cracker
• Reduces sound and particulate emissions.

Project Sky Water

Country:

• USA

Year:

• 1962

Purpose:

• Artificial cloud seeding
• Fog dispersal

Punjab Groundwater Pollution

Primary Cause:

• Intensive agricultural discharge
• Excessive pesticide use

Marine Pollution

Includes contamination of:

• Oceans
• Seas
• Estuaries
• Salt marshes

Biogeochemical Reservoirs

Large slow-moving nutrient storage systems.Examples:

• Atmosphere
• Hydrosphere
• Forest biomass

Rainforest Decline

Global rainforest coverage declined from:

• 14% of Earth's surface
• To approximately 6%

Major consequence:

• Habitat loss
• Species extinction

Nitrogen Cycle – Nitrification

Process:

• Ammonia → Nitrite → Nitrate

Performed by soil microorganisms.Nitrates become available for plant uptake.

Phosphorus Cycle

Phosphorus entering aquatic systems undergoes:

• Sedimentation

Stored in sedimentary rocks for millions of years before re-entering the cycle through weathering.

Environment vs Ecology

Environment

Includes all surrounding physical and biological conditions.

Ecology

Scientific study of interactions between organisms and their environment.

Solid Waste Collection Efficiency (India, 2021)

Collection Efficiency:

• 95.40%

Processing/Treatment:

• 50%

WMO Greenhouse Gas Bulletin

Published by:

• World Meteorological Organization (WMO)

Purpose:

• Monitor atmospheric greenhouse gas concentrations.

Data Source:

• Global Atmosphere Watch Programme.