ENVIRONMENT & ECOLOGY

BAS-204
CHAPTER 1: ENVIRONMENT

INTRODUCTION

ENVIRONMENT - In simple way environment may be defined as everything that

surrounds us. In other words, the definition can be phrased as “Our surrounding
which is formed by the interaction of living and non-living things, collectively
known as our environment”.
As per the Environment Protection Act of 1986, the environment encompasses the
totality of water, air, and land (A-Biotic), along with the interrelationships among
them, as well as their connections with human beings, other living organisms(
Biotic) , and surroundings.

Types Of Environment

1) Natural environment: The environment that comes in its existence by its own or
naturally without the influence of human beings is called as natural environment. It
operates through a self regulating mechanism known as Homeostasis.
2) Man-made environment: The environment which has been modified by human
activities is called as man-made environment. When in a specific area, the
temperature, humidity etc. are controlled by human beings – it is known as
anthropogenic environment. The increase in the scientific technology, which is the
result of human brain, is deteriorating the natural environment.

Basic Constituents (Or Components) Of Environment

The natural environment has following two parts:

1) Biotic or the living components: These include plants, animals, human
beings and microorganisms.
2) Abiotic or the non-living components: These include everything that effects
the biotic components, such as sunlight, water, air, soil, etc. Abiotic
components also include other factors such as temperature, rainfall, wind
directions and salinity levels of water and soil.
Abiotic Biotic
• Energy • Green plants
• Radiation • Non-green plants
• Temperature and heat flow • Decomposers
• Water • Parasites
• Atmospheric gases and wind • Symbionts
• Fire • Animals
• Man
• Topography
• Soil
• Geological substratum

THE SEGMENTS/PARTS OF ENVIRONMENT

The environment consists of four segments:

(1). ATMOSPHERE (sphere of air)

• Gaseous layer encircling the planet, essential for sustaining life. All
components of air, except inert gases, act as vital metabolites for living
organisms.
• It is segmented into four layers, categorized by temperature variations:
troposphere, stratosphere, mesosphere and thermosphere.
• Other gases like Hydrogen, Neon, Krypton, Methane , Helium are also present
in atmosphere.
 Gases Percentage by volume
Nitrogen 78.08 ( 75.46 by wt )
Oxygen 20.95 (23.19 by wt )
Argon 0.93
Carbon dioxide 2.04

(2). LITHOSPHERE (Sphere of soils and rocks)

• The lithosphere is the Earth's solid outermost layer, comprising the brittle
upper mantle and the crust. It lies between the atmosphere above and the
asthenosphere (a more flexible section of the upper mantle) below.
• Among all Earth's layers, the lithosphere is the most rigid.
• One of the most notable features of Earth's lithosphere is tectonic activity,
which involves the movement and interaction of massive lithospheric slabs
known as tectonic plates.
• The geothermal gradient is the rate at which temperature increases with depth
below the Earth's surface. It is around 25–30°C per kilometer in the
continental crust. It varies depending on location, rock type, tectonic activity,
and depth.
(3). HYDROSPHERE (sphere of water)

• The hydrosphere includes all the water present on or near Earth's surface.
• It extends between 10 to 20 km in thickness.
• The hydrosphere consists of water found in various forms —**liquid, vapor,
and ice—** in oceans, rivers, lakes, underground sources, and even the
atmosphere.
• Water moves continuously through a natural cycle: it evaporates, forms
clouds, falls as precipitation (rain or snow), collects in water bodies, and
evaporates again. This repeating process is known as the WATER CYCLE.
(4). BIOSPHERE (sphere of life)

• The biosphere consists of all living organisms and plays a crucial role in the
large-scale recycling of energy and matter on Earth.
• Sometimes, it is also referred as the place where atmosphere, lithosphere and
hydrosphere meets.
• The movement of matter by living organisms (biota) is not limited to specific
geographic areas but occurs on a global scale.
• The biosphere relies on solar energy for photosynthesis, which is the
foundation of food chains. Nutrient cycles like the carbon, nitrogen, and water
cycles maintain ecological balance.
• The biosphere supports biodiversity, which ensures the stability and resilience
of ecosystems.

LAYERS OF ATMOSPHERE

The Earth's atmosphere is divided into distinct layers (troposphere, stratosphere,

mesosphere, and thermosphere ), each characterized by unique temperature trends.
This variation occurs primarily due to differences in solar radiation absorption,
composition of gases, and altitude effects.
REGION ALTITUDE TEMPERATURE MAIN LAPSE
(HEIGHT), RANGE, 0C ACTIVITY RATE*
Km
Troposphere 0 to 12/15 17 to -55 Clouds +ive
formation,
rainfall
Stratosphere 12 to 50 -55 to 0 O3 formation -ive
(Ozonosphere)
Mesosphere 50 to 80 0 to -75 Meteors +ive
burning
Thermosphere 80 to 500 -75 to more than Very high -ive
1200 temperature
*LAPSE RATE – rate of change of temperature with respect to altitude

(1). TROPOSPHERE

• The troposphere is the lowest layer of the atmosphere, extending 10–15 km

above Earth's surface and containing about 75% of the atmosphere's total
mass.
• It is wider at the equator compared to the poles, and both temperature and
pressure decrease with altitude.
• Tropopause: The upper boundary of the troposphere, where temperature
reaches its lowest stable point. This region acts as a "thermal layer" or "cold
trap", preventing water vapor from escaping into space by condensing it into
ice. Without this cold trap, earth would lose all its water.
 • The majority of weather phenomena occur in the troposphere.
• Temperature decreases with altitude (~6.5°C per km) - The Earth’s surface
absorbs solar radiation and radiates heat upward, warming the air closest to the
ground. As altitude increases, the air expands due to lower pressure, causing it
to cool.
• The troposphere is heated from below, meaning the farther from the Earth’s
surface, the cooler it gets.
• Average temperature of earth surface is in range of 15 °C to 17 °C
• Example: At sea level, temperatures may be 30°C, but at 5 km altitude, they
may fall to 0°C or lower.

(2). STRATOSPHERE (Also known as ozone layer)

• Positioned directly above the troposphere, the stratosphere extends from 15

km to 50 km above Earth's surface, spanning a depth of approximately 35 km.
• The Ozone Layer: This layer consists of a thin layer of ozone molecules,
which acts as a protective shield against the Sun’s harmful ultraviolet
radiation, safeguarding life on Earth. The primary role of the ozone layer is to
absorb harmful ultraviolet radiation (UV-B and UV-C) from the sun. UV-C
(most dangerous) is completely absorbed, UV-B (can cause skin cancer,
cataracts) is mostly absorbed and UV-A (less harmful) passes through.
• The highest concentration of ozone is found between 15–35 km altitude.
• The thickness of the ozone layer varies worldwide and is generally thinner
near the equator and thicker near the poles.
• Air is dry and stable, making it ideal for jet planes. If the planes were to fly in
troposphere, heavy air in troposphere would result in more fuel consumption
and also, weather activities can cause turbulence in the plane.
• The stratosphere experiences a temperature increase with altitude due to the
absorption of sunlight by ozone. While the lower portion maintains a nearly
constant temperature, the upper part warms as elevation rises.
• The ozone layer absorbs ultraviolet (UV) radiation from the Sun, converting it
into heat. This absorbed energy warms the upper part of the stratosphere.
Since ozone concentration is higher at the mid of the stratosphere,
temperatures are warmer there than at the bottom.
• Example: The temperature rises from around -60°C at the bottom to about 0°C
at the top.
(3). MESOSPHERE

• Situated above the stratosphere, between 50 to 80 km above Earth’s surface,

the mesosphere is the coldest layer of the atmosphere, where temperature
decreases with altitude.
• Though the air in the mesosphere is extremely thin, it is still dense enough to
slow down meteors, causing them to burn up and create fiery streaks in the
night sky.
• Temperature decreases with altitude. There is no ozone layer in the
mesosphere to absorb solar radiation. The air is extremely thin, causing heat to
radiate quickly into space. As altitude increases, molecules become sparse,
reducing their ability to retain heat.
• Example: Temperatures can drop to around -90°C in the upper mesosphere,
the coldest temperature in Earth’s atmosphere.

(4). THERMOSPHERE

• Extending from 80 km above Earth to outer space, the thermosphere is

characterized by extremely high temperatures, reaching thousands of degrees.
This occurs because the few molecules present in this layer absorb large
amounts of solar energy.
• The thermosphere is part of the heterosphere, a region where gases are not
uniformly distributed but are instead layered based on their molecular masses.
• In contrast, the homosphere—which includes the troposphere, stratosphere,
and mesosphere—has gases that are evenly mixed throughout.
• Air density is extremely low.
• Temperature increases significantly with altitude (can exceed 1500°C)
• In this layer, molecules absorb high-energy radiation such as X-rays and
gamma rays from the Sun
 • Although temperatures seem extremely high, the air density is so low that heat
transfer is minimal, so it wouldn’t feel hot despite the high temperature.
• Example: Despite temperatures exceeding 1500°C, astronauts in orbit feel cold
because heat transfer via air molecules is negligible.

IONOSPHERE

• The ionosphere is a section of Earth’s upper atmosphere, ranging from 60 km

to 1,000 km in altitude. It overlaps with the thermosphere and includes
portions of the mesosphere and exosphere.
• This region is ionized by solar radiation, contributing to atmospheric
electricity and serving as the inner boundary of the magnetosphere.
• The ionosphere is crucial for radio communication, as it affects radio wave
propagation, enabling long-distance transmission across Earth.

Exosphere

• Outermost layer, merging into outer space.

• Contains extremely sparse gas molecules like hydrogen and helium.
• Temperature is stable or slight increase with altitude.
• Reason for Temperature Stability: Molecules are widely dispersed and may
travel great distances without colliding, resulting in minimal heat transfer.
While solar radiation is intense, the extremely low air density means there’s
virtually no measurable temperature in the traditional sense.

IMPORTANCE OF ENVIRONMENTAL SCIENCE

• Environmental studies aware us about the valuable natural resources, their

importance and conservation methods.
• Environmental studies provide knowledge about the ecology and
biodiversity.
• Environmental studies help us to find ways to maintain ecological balance.
• Environmental studies help us to solve the big environmental problems like
Environmental Pollution, Urbanization, Deforestation, Desertification,
Global Warming, Acid Rain, Ozone Layer Depletion etc.
SCOPE OF ENVIRONMENTAL SCIENCE/STUDIES:

There are various fields/areas in which we can see the scope of environmental
science.
• Natural Resources, their conservation and management.
• Ecology and Biodiversity conservation
• Environmental pollution and its control
• Global environmental issues and their control measures: Such as-Global
warming, Ozone layer depletion, Acid rain, Desertification, Deforestation,
Urbanization etc.

THE NEED OF PUBLIC AWARENESS ABOUT THE ENVIRONMENT

• The environment is degrading day by day because of, increasing population,

rapid industrialization, urbanization, deforestation and environmental
pollution.
• All these problems have disturbed the ecological balance in such a way that
the survival of life on earth has been seriously threatened. Therefore public
awareness is must for protection of environment.
• Public awareness can be achieved through environmental education i.e.
people should be told about environment and its importance.
• Environmental education or environmental awareness among public can be
spread through books, magazines (for ex: down to earth), schools/
colleges/institutes/university, news paper, media, television, radio, eco-
clubs, Government and Non-Governmental Organizations (NGO’S).
 • Public participation is possible only when the public is aware about the
environment and environmental issues (problems)”.

MULTIDISCIPLINARY NATURE OF ENVIRONMENTAL STUDIES

Environmental science is a multidisciplinary science and it includes not only life
science (i.e. zoology, botany) but also chemistry, physics, mathematics, geology,
geography, atmospheric science, medical science, history, social science and
statistics etc. (HOW? – SELF STUDY)
CHAPTER 2: ECOLOGY AND ECOSYSTEM

ECOLOGY

The word 'Ecology' is derived from the Greek word "Oikos" which means
habitation and "logos" means study. Ecology was first described as a separate field
of knowledge in 1866 by German zoologist Ernst Haeckel. He invented the word
"Oekologie" for the relation of animal to its organic as well as inorganic
environment. Ramdeo Misra is known as the father of ecology in India.
Ecology is a branch of biology that attempts to understand the relationship between
living organisms and their environment, and the associated energy flows. Under
ecology, the study of three features of ecosystem is done:
• Interaction of organism as a whole with their physical environment.
• Interaction among members of different species.
• Interaction among members of a particular species.

Levels of Ecological Organization

Ecology is structured into six primary levels of organization.

Individual

An individual refers to a single living organism that can function independently.

Examples include a lion, an elephant, a tiger, and a wolf.

Population

In ecological terms, a population is defined as a group of individuals belonging to

the same species, which interbreed and exist together in a particular space and
time.
Note: Species: A species is defined as a group of organisms that share similar traits
and are capable of interbreeding to produce fertile offspring. Humans belong to the
species Homo sapiens.

Community

Communities consist of populations of plants and animals coexisting in a shared

habitat. To sustain life, individuals of one species interact with those of other
species. A community is, therefore, defined as a collection of different species'
populations (both plant and animal) that occupy a particular area at the same time.
The number and size of species in a community may vary significantly.

Ecosystem

An ecosystem consists of a community of living organisms interacting with the

nonliving components of their environment (such as air, water, and mineral soil) as
an integrated system. Biotic (living) and abiotic (nonliving) factors are interlinked
through nutrient cycles and energy flow, maintaining the balance of the ecosystem.

Biome

A biome refers to a large-scale grouping of terrestrial ecosystems within a

continent that share similar vegetation structure, physical appearance,
environmental conditions, and characteristic animal communities. Aquatic
ecosystems are not classified as biomes. Instead, they are divided into life zones,
which are distinct regions with unique plant and animal life on the basis of salinity
levels, dissolved nutrients, water temperature, and the depth of sunlight penetration

Biosphere

The biosphere is the part of Earth where life exists. It is a highly integrated and
interactive zone that includes the atmosphere (air), hydrosphere (water), and
lithosphere (land). The biosphere is a thin layer surrounding the Earth's surface
where life thrives. It is absent in the extreme regions of the North and South Poles.

ECOSYSTEM

• An ecosystem is a system where living organisms continuously interact with

both biotic (living) and abiotic (non-living) components in their environment.
These biotic and abiotic components are interconnected through nutrient
cycles and energy flows.
• Ecosystems are characterized by the interactions between organisms and their
surroundings, and they can vary in size, though they generally occupy specific,
limited areas.
• The term "ecosystem" was coined by the British ecologist Arthur George
Tansley in 1935.
• Example: A drop of water containing bacteria is an ecosystem, just as the
entire Earth can be considered an ecological model known as the Ecosphere,
the largest ecosystem.
Fig: Components of an Ecosystem

Fig: Types of Ecosystems

Salient Features of Forest Ecosystem

Salient Features of Desert Ecosystem

Salient Features of Grassland Ecosystem

Biotic components

Abiotic Secondary Tertiary

Primary
components Producers consumers or consumers consumers
Decomposers
or or
HERBIVORE
carnivore1 carnivore2
 Frog,
Grasshopper, Hawk/
Soil, Water, Grasses, Snake,
Rabbit, Eagle and Bacteria
Sunlight, Herbs and Lizards,
Mouse, Deer, Vultures and Fungi
Air Shrubs Birds, Fox,
Sheep Etc. Etc.
Jackal Etc.

Salient Features of Pond Ecosystem

Functions of an Ecosystem

The main functions of an ecosystem are:

• Energy flow: It takes place with the help of food chain and food web. The
energy flow is unidirectional and non-cyclic.
• Material flow or nutrient cycling or biogeochemical cycling: It means the
circulation or movement of nutrients between living and non-living
components of ecosystem. For example-Nitrogen cycle, sulphur cycle, carbon
cycle (= CO2 cycle), oxygen cycle, water cycle, Phosphorus cycle etc.
• Productivity: It means the production of biomass at producers and consumers
level.
• Homeostasis (=Ecological balance): It means a balance between living and
non-living components of ecosystem.
• Regulatory functions or ecological services: Regulation of climatic conditions
(rain, temperature etc.), Regulation of nutrient cycling (=biogeochemical
cycling), Regulation of hydrological cycle (water cycle), Purification of air,
Control of environmental pollution, Soil formation, Pollination etc.
Ecological Niche

In nature, multiple species can share the same habitat but carry out different
ecological roles. The unique function of a species within its habitat is known as its
niche. The habitat of a species can be compared to its address, while its niche
represents its role or profession—describing the specific activities and interactions
that enable its survival.
For example, a garden spider's niche includes being a predator that hunts for prey
among plants, while an oak tree's niche involves dominating a forest canopy and
converting sunlight into food.

Ecotone

An ecotone is a transitional zone where two or more ecosystems meet and merge.
It serves as a boundary between ecological communities. Ecotones can vary in
size, ranging from small local areas (e.g., between a field and a forest) to larger
regional zones (e.g., where a forest meets a grassland).
• Biodiversity is higher in ecotones than in other ecosystems due to the presence
of species from both adjoining habitats.
• Example: A mangrove forest functions as an ecotone between marine and
terrestrial ecosystems. Other examples include grasslands, estuaries, and
riverbanks.
• Their environmental conditions are intermediate, blending characteristics of
adjacent ecosystems—making them a zone of tension where species
interactions are heightened.
• Ecotones display a gradual transition in species composition, where one
community increases while another declines.
• In certain zones, the species diversity and population density of some
organisms are significantly higher compared to the adjacent ecosystems. This
phenomenon is known as the Edge Effect.

What is ecological succession? (Self study)

What is balanced ecosystem? (Self study)

FOOD CHAIN

A food chain represents a sequence of organisms where each one feeds on the
previous one. It illustrates the transfer of food energy from green plants
(producers) to various heterotrophs at different trophic levels.
Definition: “The transfer of food energy from organism to organism i.e. from
producers to consumers to decomposers in an ecosystem is known as food chain”.
Components of a food chain are:
• Producers
• Consumers
• Decomposers

Autotrophs (Producers)

Autotrophs serve as the primary food producers in an ecosystem. The total amount
of radiant energy stored through photosynthesis in green plants is referred to as
Gross Primary Production (GPP). This is also known as total photosynthesis or
total assimilation.

Herbivores

Herbivores, also known as primary consumers, feed directly on plants.

Examples include insects, birds, rodents, and ruminants.

Carnivores

Secondary consumers prey on herbivores, while tertiary consumers feed on other

carnivores.
Examples: frog, dog, cat, and tiger.
Omnivores

Omnivores consume both plant and animal matter ie these are primary , secondary
or even tertiary consumers depending upon their diet.
Examples: pig, bear, and humans.

Food chains in different ecosystems

Terrestrial Food Chains:

• Grass → Grasshopper → Frog → Snake → Hawk:
This example illustrates a simple grazing food chain where grass (producer) is
eaten by a grasshopper (primary consumer), which is then eaten by a frog
(secondary consumer), and so on.
• Oak Tree → Deer → Wolf:
This chain shows a producer (oak tree) being consumed by a herbivore (deer),
which is then preyed upon by a carnivore (wolf).
• Flower → Butterfly → Bird → Fox:
This chain shows a producer (flower) being consumed by a herbivore (butterfly),
which is then preyed upon by a carnivore (bird), and finally a larger carnivore
(fox).
• Grass → Cow → Human:
A common example where grass (producer) is eaten by a cow (primary consumer),
which is then consumed by a human (secondary consumer).

Aquatic Food Chains:

• Phytoplankton → Zooplankton → Small Fish → Large Fish → Shark:
This chain illustrates an aquatic food chain where phytoplankton (producer) are
eaten by zooplankton (primary consumer), which are then consumed by small fish
(secondary consumer), and so on.
• Algae → Snail → Fish → Bird:
This chain shows a producer (algae) being consumed by a herbivore (snail), which
is then eaten by a fish (secondary consumer), and finally a bird (tertiary consumer).

Detritus Food Chain: ( Generally found in Mangroves)

• Fallen Leaves → Worms → Bird:
This chain shows how dead organic matter (fallen leaves) is consumed by
decomposers (worms), which are then eaten by a bird (secondary consumer).
• Dead Fish → Bacteria → Shrimp → Fish:
This chain shows how dead fish are decomposed by bacteria, which are then
consumed by shrimp, which are then eaten by fish.
 • Parasitic Food Chain:
Tree → Fruit-eating Bird → Lice: This chain illustrates a parasitic relationship
where a tree (producer) is consumed by a bird, and the bird is then parasitized by
lice.

FOOD WEB

A food web represents the complex interconnection of multiple food chains,

illustrating the feeding relationships within an ecological community. It visually
depicts "who eats whom" and is also referred to as a consumer-resource system.

Fig: Food web

IMPORTANCE OF FOOD CHAINS AND FOOD WEBS

• They enable the flow of energy and the recycling of nutrients.

• They help maintain ecological stability.
• They clarify feeding relationships and interactions among organisms in an
ecosystem.
• Food chains demonstrate biological magnification, where certain non-
biodegradable substances (such as pesticides and metallic pollutants)
accumulate in higher concentrations at higher trophic levels.
TROPHIC LEVELS

An ecosystem is a fundamental unit where complex natural communities derive

their food from plants through a series of steps. These steps can range from one to
four, corresponding to the first, second, third, and fourth trophic levels (Trophe =
nourishment) or food levels. Organisms are categorized into different trophic levels
based on their mode of nutrition:
• Producers (Autotrophs): Green plants form trophic Level-I by producing their
own food.
• Primary Consumers (Herbivores): Organisms that feed on producers belong to
Trophic Level-II and are classified as heterotrophs.
• Secondary Consumers (Carnivores): These heterotrophs, feeding on
herbivores, are part of Trophic Level-III.
• Tertiary Consumers (Carnivores): Organisms in Trophic Level IV, feeding on
secondary consumers, are also heterotrophs.
• Quaternary Consumers (Top Carnivores): The highest level, Trophic Level V,
consists of heterotrophs that feed on tertiary consumers.

Fig: Trophic levels

ENERGY FLOW IN AN ECOSYSTEM

• Flow of food energy from one trophic level to another in an ecosystem is

called energy flow.
• Energy flow takes place with the help of food chain and food web.
• Sun is the ultimate source of energy in an ecosystem.
 • The flow of energy in an ecosystem is unidirectional because once the energy
flows from the first to next trophic level, it cannot reverse back to first trophic
level.
• The flow of energy in an ecosystem is non-cyclic.

Lindeman’s Ten Percent Law

This principle states that only 10% of the energy from organic food is passed to the
next trophic level, while the remaining 90% is lost due to respiration, metabolism,
or incomplete digestion. It highlights the inefficiency of energy transfer in food
chains. The law emphasizes that energy conservation is most efficient when
consuming food sources closest to the initial energy producer (plants).The ten
percent energy law was given by Lindeman (1942).
ECOLOGICAL PYRAMIDS

These are the graphical representation of various trophic levels of the food chains
in an ecosystem. It begins with producers at the base and progresses through
successive trophic levels, culminating at the apex.
Ecological pyramids are classified into three types:
Pyramid of numbers
Pyramid of biomass
Pyramid of energy or productivity

Pyramid of Numbers

This concept illustrates the relationship between the number of primary producers
and consumers at various trophic levels. The base of the pyramid signifies the
foundation of food production, supporting higher trophic levels.
The pyramid structure can be upright (as seen in grassland, terrestrial, or pond
ecosystems) or inverted (as observed in parasitic ecosystems), depending on the
type of ecosystem and its food chain.

Fig: Pyramid of numbers

Pyramid of Biomass

To address the limitations of the pyramid of numbers, the pyramid of biomass is

used. In this method, organisms at each trophic level are weighed instead of being
counted. This results in a pyramid of biomass, which represents the total dry
weight of all organisms at each trophic level at a specific time. Biomass is
expressed in g/m². The amount of biomass present at the time of sampling is
referred to as standing crop or standing biomass.
The biomass pyramid can be upright (as seen in grassland ecosystems) or inverted
(as observed in pond ecosystems).
 Fig: Pyramid of biomass

Pyramid of Energy

Energy pyramids are a powerful tool for comparing the functional roles of various
trophic levels within an ecosystem.
At each trophic level, the energy content is always smaller than that of the
preceding level.
Consequently, the energy diminishes progressively at higher trophic levels,
ensuring that the pyramid remains upright.

BALANCED ECOSYSTEM

BIOACCUMULATION AND BIOMAGNIFICATION

Non-degradable pollutants tend to pass through different trophic levels within an

ecosystem. These pollutants consist of substances that cannot be broken down or
processed by living organisms, such as chlorinated hydrocarbons. The movement
of these pollutants occurs through two primary processes.

Bioaccumulation

• Bioaccumulation refers to the buildup of chemicals, such as pesticides or other

substances, within an organism over time.
• It occurs when an organism absorbs a potentially harmful substance at a rate
that exceeds its ability to break it down or excrete it.
• The longer the biological half-life of a toxic substance, the higher the risk of
chronic poisoning, even if the environmental concentration is relatively low.
Biomagnification

• Biomagnification describes the increasing concentration of toxic substances in

the tissues of organisms at higher levels in a food chain.
• Also referred to as bio amplification or biological magnification, this process
occurs due to:
• Persistence: The substance resists breakdown by natural environmental
processes.
• Food chain energetics: The substance's concentration progressively
increases as it moves up the food chain.
• Low or no internal degradation/excretion: Often due to the substance
being water-insoluble.

Fig: Bioaccumulation and Biomagnification

SYMBIOSIS

Symbiosis refers to a close relationship between two or more different species.

Unlike regular interactions, symbiotic species live together. Many species engage
in symbiotic relationships as they provide mutual benefits. However, some forms
of symbiosis can be harmful to one or both species. Symbiotic relationships are
classified into:
Obligate symbiosis – A relationship in which species depend on each other for
survival. For eg: Termites and Protozoa: Termites cannot digest wood without the
help of protozoa in their gut, and the protozoa cannot survive outside of the
termite's digestive system
Facultative symbiosis – A relationship where species live together by choice rather
than necessity. For eg: Plants and Pollinators: Plants benefit from pollination by
animals, and the animals get food (nectar, pollen) from the plants, but both can
survive without the interaction
CHAPTER 3: EFFECTS OF HUMAN ACTIVITIES

Humans rely on the environment for their survival. All our basic needs are met through the resources it
provides—whether it's food, clothing, shelter, or air, we depend entirely on the environment. However, in
the process of fulfilling these needs, we often end up harming it. Below are some human activities that
have a negative impact on the environment.

FOOD
Food is any substance that is usually composed of carbohydrates, fats, proteins and water that can be
eaten or drunk by an animal or human for nutrition or pleasure. Items considered food may be sourced
from plants, animals or other categories such as fungus or fermented products like alcohol.
• Because of increasing population, food production requirements are increasing.
• Half of the world's habitable land is used for food production.
• Food production requires freshwater resources and hence are responsible for their depletion.
• 94% of mammal biomass is livstock.
• Food production is the one of the root causes for process like eutrophication.
Undernourishment: Lack of sufficient calories in available diet. Food and Agricultural Organisation, the
average minimum daily calorific requirement is 2500 calories per day. People taking less than its 90%
daily requirement are said to be undernourished.
Malnutrition: Lack or deficiency of specific constituents of food, such as proteins, vitamins or certain
essential elements.
Overnutrition: Results from eating too much, eating too many of the wrong things, not exercising
enough, taking too many vitamins or other dietary replacements.

HOUSING
• Use of Non-renewable Resources: Policies governing the design, construction and renovation of
housing do not impose any requirement through legislation, regulation or fiscal incentives to
minimise the use of non-renewable resources.
• Energy Consumption: Energy consumption in houses accounts for significant percentage of the
total energy consumption each year. No regulation addresses energy efficiency standards in existing
houses.
• Water Consumption: Two-thirds of water is used to flush water closet, wash clothes or dishes and
for bathing. Except when there are water shortages there is no expectation that households will
conserve or re-cycle water.
• Neighbourhoods: All neighbourhoods have an ‘ecological footprint’. Neighbourhoods which are
most compact and self-contained with more local shopping, employment and community facilities,
have a smaller “footprint’.

AGRICULTURE
• Biodiversity: Some current agricultural land management practices continue to alter biodiversity.
Agricultural systems with little crop rotation provide large areas of uniform habitat, thus reducing
biodiversity. Water draining from agricultural fields can transport nutrients, eroded sediments, and
pesticides to downstream areas, affecting aquatic biodiversity.
• Greenhouse Gases: Agriculture has the potential to act both as a source and as a sink for several of
the
• atmgspheric greenhouse gases that are believed to be responsible for climatic changes.
 • Energy Use: Agriculture is a direct consumer of energy for use in such activities as tilling,
harvesting, heating and ventilation.
• Impact of Agriculture on Climate Change: The agricultural sector is a driving force in the gas
emissions and land use effects thought to cause climate change.
• Effect of Modern Agriculture:

Water Logging: Occurs when water table rises and eventually approaches the soil surface rendering the
root zone unsuitable for crop growth.

INDUSTRY
• Air pollution is a visible source of environmental contaminants, created mainly by industry’s waste
products and combustion of hydrocarbons by industry and in transportation.
• Releases huge amount of hazardous waste and also a major source of water pollution.
• Industries are one of the reasons for depletion of natural resources.
• Industrial accidents such as Chernobyl accident has huge environmental consequences.

MINING
• It causes deforestation. In order to mine trees and vegetation are cleared and burned.
• Stripping of large areas of topsoil and of all flora and fauna in addition to man made constructions:
• Underground coal mining can require the removal of almost an entire layer of material deep under
the surface. When the timber supports collapse it leads to subsidence. The subsidence can mean
economic loss to people above or damage to natural areas. It can even cause cracks in river beds,
leading to loss of river flow.
• Digging up chemically-reactive minerals which are harmless when underground, but when extracted
react spontaneously with oxygen and water. The extraction of sulphide ores ineviatably produces
 sulphuric acids and metal ions. This emission known as ‘acid mine drainage’, occurs in active mines
and in places where waste is stored.
• Adding potentially toxic chemicals. such as cyanide, to the ore to extract the metal, which increases
the toxicity level of the waste.
• Using large amounts of energy and water, which are often scarce
• Many mines require tailings dams to prevent waste being washed into the rivers. Unethical miners
can dispense with the dams, to save costs, resulting in massive pollution downstream. In other cases,
the tailing dams can overflow and even breach during periods of heavy rain.
• Asbestos mining causes the dispersal of asbestos into the environment. This will cause deaths
among local residents and workers, often several decades later. Fortunately, the mining and use of
asbestos are banned in most parts of the world.
• Environmental issues can include erosion, formation of sinkholes and loss of biodiversity

TRANSPORT
• Emissions: First and foremost are emissions. Except for such modes as as walking, bicycling and
sailing, transportation generally emits pollutants into the air. Transportation is responsible for
significant releases of carbon monoxide, VOCs, nitrogen oxides carbon dioxide and benzene.
• Noise: Noise can cause stress or aggravate existing medical conditions and interfere with daily
activities such as communicating or sleeping. High levels of noise can depress property values.
• Expansion: Transport allows urban expansion, which can consume or damage valuable agricultural
lands and natural habitats. Habitat fragmentation by roads or rail tracks can lead to provide
corridors for the spread of pests and weeds.
• Material Consumption: Transportation also draws on the natural environment indirectly by using
products from the energy, minerals and manufacturing sectors.
• Energy: From a sustainability point of view by far the most worrisome resource used by
transportation is energy.
• Spills onto Land and Water: Spills include the relatively infrequent but sometimes catastrophic
accidental discharge of hazardous materials during transport, including, ironically spills of oil used
to fuel transportation in the first place. Spills also include the deposition and run-off of toxic
material from vehicles themselves.
CHAPTER 4: ENVIRONMENTAL IMPACT ASSESSMENT AND
SUSTAINABLE DEVELOPEMENT

Environmental Impact Assessment (EIA)

Introduction
• Environmental Impact Assessment (EIA) is a process of evaluating the likely environmental
impacts of a proposed project or development, taking into account inter-related socio-economic,
cultural and human-health impacts, both beneficial and adverse.
• Till 1994, environmental clearance from the Central Government was an administrative decision
and lacked legislative support. On 27 January 1994, the then Union Ministry of Environment and
Forests, under the Environmental (Protection) Act 1986, promulgated an EIA notification making
Environmental Clearance (EC) mandatory for expansion or modernisation of any activity or for
setting up new projects listed in Schedule 1 of the notification.
Salient Features of 2006 Amendments to EIA Notification
• The Ministry of Environment, Forests and Climate Change (MoEFCC) notified new EIA
legislation in September 2006.
• The notification makes it mandatory for various projects such as mining, thermal power plants,
river valley, infrastructure (road, highway, ports, harbours and airports) and industries including
very small electroplating or foundry units to get environment clearance.
• Environment Impact Assessment Notification of 2006 has decentralized the environmental
clearance projects by categorizing the developmental projects in two categories, i.e., Category A
(national level appraisal) and Category B (state level appraisal).
• Category A projects require mandatory environmental clearance and thus they do not undergo the
screening process.
The EIA Procedure
EIA involves the steps mentioned below. However, the EIA process is cyclical with interaction between
the various steps.
1. Project Proposal: Any proponent embarking on any major development project shall inform IAA
(Impact Assessment Agency) in writing by the submission of project proposal which shall include
all relevant information available including a land use-map.
2. Screening: Done to see whether a project requires environmental clearance as per the statutory
notifications.
3. Scoping: Scoping is a process of detailing the terms of reference of EIA. The Ministry of
Environment and Forests has published guidelines for different sectors, which outlines the
significant issues to be addressed in the EIA studies.
4. Baseline Data Collection: Baseline data describes the existing environmental status of the
identified study area. The site-specific primary data should be monitored for the identified
parameters and supplemented by secondary data if available. Primary data are those which need to
be collected in the field to define status of the environment (like air quality data, water quality data
etc.). Secondary data are those which have been collected over the years and can be used to
understand the existing environmental scenario of the study area.
5. Impact Prediction and Assessment of Alternatives: Impact prediction is a way of mapping the
environmental consequences of the significant aspects of the project and its alternatives. For every
project, possible alternatives should be identified and environmental attributes compared.
Alternatives should cover both project location and process technologies. Alternatives should then
 be ranked for selection of the best environmental optimum economic benefits to the community at
large. Once alternatives have been reviewed, a mitigation plan should be drawn up for the selected
option and is supplemented with an Environmental Management Plan (EMP) to guide the
proponent towards environmental improvements. The EMP is a crucial input to monitoring the
clearance conditions and therefore details of monitoring should be included in the EMP.
6. EIA Report: An EIA report should provide clear information to the decision maker on the different
environmental scenarios without the project, with the project and with project alternatives. The
proponent prepares detailed Project report and provides information in logical and transparent
manner.
7. Public Hearing: The State Pollution Control Boards will conduct the public hearing before the
proposals are sent to MOEF for obtaining environmental clearance. Any one likely to be affected by
the proposed project is entitled to have access to the Executive Summary of the EIA. The affected
persons may include: (i) Bonafide local residents: (ii) Local associations: (iii) Environmental groups
active in the area: (iv) Any other person located at the project sites of displacement. They are to be
given an opportunity to make oral/written suggestions to the State Pollution Control Board as per
Schedule V.
8. Decision-making: Decision-making process involve consultation between the project proponent
and the impact assessment authority. The decision on environmental clearance is arrived at
through a number of steps including evaluation of EIA and EMP.
9. Monitoring the Clearance Conditions: Monitoring has to be done to ensure that the commitments
made are complied with and also to observe whether the predictions made in the EIA reports are
correct or not. Monitoring also enables the regulatory agency to review the validity of predictions
and the conditions of implementation of the Environmental Management Plan (EMP).
Legal provisions for Public Hearing
Recent Amendment in the Public hearing nofifications is that hearings are now mandatory for all projects
to which the EIA notification applies. In support of this new requirement, the process includes provisions
for public access to information.
• Project proponents are required to provide the SPCB (State Pollution Control Board) with an
executive summary of the project.
• Public access to executive summaries is available at District Collectors’ Offices, District Industry
Centers, the office of the Zila Parishad or Commissioner of the municipal corporation/local body,
and SPCB state and Regional offices.
• SPCBs are required to give notice in at least two newspapers widely circulated in the region around
the project, mentioning the date, time and place of public hearings.
 • Suggestions, views, comments and objections of the Public shall be invited within 30 days from the
date of publication. Local residents, environmental groups and others located at the project site
likely to be affected can participate in the hearings.
• The hearing panels includes a representative of the SPCB, the District Collector, a state government
representative for the relevant sector under investigation, a representative of the central Ministry of
the Environment and Forests, not more than three representatives of local bodies such as
municipalities or panchayats, and not more than three senior citizens nominated by the District
Collector.
• A time limit of 60 days has been laid down for completion of public hearing.
Importance of EIA
• EIA links environment with development for environmentally safe and sustainable development.
• EIA provides a cost effective method to eliminate or minimize the adverse impact of developmental
projects.
• EIA enables the decision makers to analyse the effect of developmental activities on the
environment well before the developmental project is implemented.
• EIA encourages the adaptation of mitigation strategies in the developmental plan.
• EIA makes sure that the developmental plan is environmentally sound and within the limits of the
capacity of assimilation and regeneration of the ecosystem.
Shortcomings of EIA Process
• Applicability: There are several projects with significant environmental impacts that are exempted
from the notification either because they are not listed in schedule I, or their investments are less
than what is provided for in the notification.
• Composition of expert committees and standards: It has been found that the team formed for
conducting EIA studies is lacking the expertise in various fields such as environmentalists, wildlife
experts, Anthropologists and Social Scientists.
• Public hearing: Public comments are not considered at an early stage, which often leads to conflict
at a later stage of project clearance. The data collectors do not pay respect to the indigenous
knowledge of local people.
• Quality of EIA: One of the biggest concerns with the environmental clearance process is related to
the quality of EIA report that are being carried out.
• Lack of Credibility: There are so many cases of fraudulent EIA studies where erroneous data has
been used, same facts used for two totally different places etc. Often, and more so for strategic
industries such as nuclear energy projects, the EMPs are kept confidential for political and
administrative reasons.

SUSTAINABLE DEVELOPMENT
The philosophical background of the concept of ‘Sustainable Development’ is rooted in the Neo-
Determinism theory, which states that humans and the environment are equally important and influence
each other to maintain a dynamic equilibrium. The term ‘Sustainable Development’ was first introduced
by the IUCN (International Union for Conservation of Nature) and was popularized by the Brundtland
Report, published in 1987 under the title Our Common Future.
The term sustainable development can be defined as “Development that meets the needs of the present
without compromising the ability of future generations to meet their own needs.”
Pillars of sustainable development
• Environmental Sustainability: This emphasizes on area of conservation of biodiversity hotspots.
increase in forest cover, watershed protection, and adoption of holistic approach. Equally important
 are reduction of environmental threats, environmental pollution and adoption of environment
friendly clean and green technologies to mitigate local to global level environmental problems.
• Economic Sustainability: This emphasizes on utilization of natural resources for cultivation,
industrialization, creating job opportunities etc. Also, it promotes economic self-sustenance of
development projects through measures like adequate budgeting, budget transparency and financial
incentive.
• Social Sustainability: This focuses on upgrading human environmental quality of life with
fulfillment of basic needs and transforming humans from most dangerous animal to most important
creative resource. It emphasizes local communities be well-informed on tips of sustainable ways of
resource utilization.
Objectives
• It should protect our biodiversity
• It should prevent soil erosion
• It should slow down the population growth
• It should increase forest cover
• It should cut off the emissions of CFC, SOx, NOx, and COx
• It should reduce waste generation
• It should eliminate poverty and deprivation
• It should bring benefits to all
Unsustainable to Sustainable Development
• By using appropriate technology which is locally adaptable, ecofriendly, resource-efficient and
culturally suitable.
• By adopting reduce, reuse and recycle approach
• By prompting environmental education and awareness
• The demand should be reduced upto the system’s carrying capacity that a system can sustain on a
long-term basis. Consumption should not exceed regeneration and changes should not be allowed to
occur beyond the tolerance capacity of the system. Components of carrying capacity are supporting
capacity, i.e. the capacity to regenerate and Assimilative capacity i.e. the capacity to tolerate
different stresses.
Obstacles in the Path of Sustainable Development
• Pollution
• Over-Population
• Poverty
• Discrimination (=inequity) against women
• Caste based fight
• Religion based fights
• Dirty politics
• Problems of female infanticide, child marriage, child labour and dowry
• Illiteracy (lack of education)
• Corruption