What is Environment??
Formed from two words,‘environ’ and‘ment’ which means
‘encircle’ or‘all around’
Environment is a complex of many variables which surround
man as well as living organisms.Any external force,
substance or condition, which surrounds and effects the life
of the organism in any way, becomes a factor of its
Troposphere - sea level/surface of
earth to 8-16km. 75% of atmosphere’s
mass contained here.Water vapor,
Stratosphere- Extends to an altitude of
50kms. Ozone layer- absorb ultraviolet
Mesosphere – extends till 85kms. In
temperature decreases as the altitude
increases (temp. as low as -93 degree
Celsius).The upper mesosphere is also
the region of the ionosphere.
Thermosphere – extends to an altitude
of 600 kms.Temperature increases
with altitude (upto 1727 degree
Exosphere- Layer that merges with
interplanetary space. Hydrogen and
helium are prime gases.
Evaporation is the process by which
water changes from a liquid to a gas
Transpiration is the process by
which moisture is carried through
plants from roots to small pores on
the underside of leaves, where it
changes to vapor and is released to
the atmosphere. It is essentially
evaporation of water from plant
They are collectively
Precipitation is any product of the
condensation of atmospheric water
vapour that falls under gravity. eg.
The Earth is an oblate spheroid. It is composed
of a number of different layers as determined
by deep drilling and seismic evidence.These
The core, which is approximately 7,000
kilometers in diameter (3,500 kilometers in
radius) and is located at the Earth's center.The
core is a layer rich in iron and nickel that is
composed of two layers: the inner and outer
The mantle, which surrounds the core and has
a thickness of 2,900 kilometers.
The crust, which floats on top of the mantle. It
is composed of basalt rich oceanic crust and
granitic rich continental. Crust depth -40-
kilometer (25-mile), has just 1% of Earth’s
mass—contains all known life in the universe.
Biosphere can be viewed as a system or a set of functions that
operates together and is dependent on each other.The biosphere is
the biological component of earth systems, which also include the
lithosphere, hydrosphere, atmosphere and other "spheres"*.
The atmosphere of Earth is the layer of gases surrounding the
planet earth that is retained by Earth's gravity.
The hydrosphere in physical geography describes the combined
mass of water found on, under, and over the surface of a planet.
Earth's lithosphere includes the crust and the uppermost mantle,
which constitute the hard and rigid outer layer of the Earth.
*[e.g. cryosphere (the frozen water part of the earth system), anthrosphere (environment that is
made or modified by. humans for use in human activities) etc.].
An ecosystem is a community of living organisms in
conjunction with the nonliving components of their
environment interacting as a system.
Biotic (Plants and animals)
Abiotic (things like air, water and mineral soil)
There are many examples of ecosystems -- a pond, a forest,
an estuary, a grassland.
These biotic and abiotic components are regarded as linked
together through nutrient cycles and energy flows.
Energy enters the biological system as light energy, or photons, is transformed into chemical energy in
organic molecules by cellular processes including photosynthesis and respiration, and ultimately is
converted to heat energy.This energy is dissipated, meaning it is lost to the system as heat; once it is lost
it cannot be recycled. Without the continued input of solar energy, biological systems would quickly shut
down.Thus the earth is an open system with respect to energy.
Elements such as carbon, nitrogen, or phosphorus enter living organisms in a variety of ways. Plants
obtain elements from the surrounding atmosphere, water, or soils.Animals may also obtain elements
directly from the physical environment, but usually they obtain these mainly as a consequence of
consuming other organisms.These materials are transformed biochemically within the bodies of
organisms, but sooner or later, due to excretion or decomposition, they are returned to an inorganic
state. Often bacteria complete this process, through the process called decomposition or mineralization.
During decomposition these materials are not destroyed or lost, so the earth is a closed system with
respect to elements (with the exception of a meteorite entering the system now and then).The elements
are cycled endlessly between their biotic and abiotic states within ecosystems.Those elements whose
supply tends to limit biological activity are called nutrients.
In reality the organization of biological systems is much more complicated than can be represented by a
simple "chain".There are many food links and chains in an ecosystem, and we refer to all of these
linkages as a food web. Food webs can be very complicated, where it appears that "everything is
connected to everything else”
Environment resources refer to components that have an intrinsic
value of their own, or are of value for long term sustainability and
use by human.
Renewable resources - Capable of natural regeneration . Once
degraded beyond certain level, they may never recover. Eg. clean
water, Clean air, Soil, flora, fauna
Non-renewable resources - Rate of their renewal is so slow that they
are regarded as available only in fixed quantities. Eg. Minerals, ground
Continuous resources – Eg. Solar energy, wind, gravity, tidal energy
Extrinsic resources - prone to breakdown and degradation. Eg.
Types of FreshWater Resources
Standing water bodies (lakes, reservoirs)
Flowing water bodies (Surface water- streams, rivers)
(97.6% salty sea water, non-sea water- 87% of solid polar cap, 12%
ground water, 1% surface water)
If burning issues related to fresh water ecosystems such as
pollution and over exploitation are not addressed immediately, the
diverse communities found in lakes, rivers, and wetlands will be
lost in no time.
Greater danger of further losses from dams, pollution, overfishing,
and other threats.
Oceans and Coasts
Economic opportunities (industries, tourism, mineral
extraction, shipping) offered by coastal areas lead to high
population growth rates and consequent environmental
Mangrove forests are under pressure to be exploited for their
wood resources and because the land beneath them can be
drained and reclaimed from the sea for development.
Corals and marine life under threat due to shipping/ port
Global energy requirement – Fossil fuel [Oil (38%), Coal and Lignite
(26.5%), Natural gas (20.9%)] and renewable energy.*
Air pollution – Pollutants that come from the combustion of fossil fuels
include sulphur dioxide (SO2), nitrogen oxides (NOx), particulate
matter (PM), carbon monoxide (CO), carbon dioxide (CO2)
Eg. Nitrogen oxide
Emissions -Cars and trucks, Coal-fired power plants, Large industrial
operations, Ships and airplanes
which contribute to the formation of smog and acid rain
Smog- type of air pollution derived from vehicular emission from internal combustion
engines and industrial fumes that react in the atmosphere with sunlight to form
secondary pollutants. It is harmful for people with heart and lung conditions such
as bronchitis and asthma. It can inflame breathing passages, decrease the lungs'
working capacity, cause shortness of breath, pain when inhaling deeply, wheezing, and
Acid rain - is a rain or any other form of precipitation that is unusually acidic, meaning
that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects
on plants, aquatic animals and infrastructure.Acid rain is caused by emissions of sulfur
dioxide and nitrogen oxide, which react with the water molecules in
the atmosphere to produce acids.
*Source: Essentials of Environmental studies- Kurian Joseph, R. Nagendran
Immense variety of species of microbes, plants, insects,
amphibians, reptiles, birds, fish and mammals can be part of
wetland.They provide great volume of food that attract many
Help ground water recharge
Deposit nutrient rich silt
(Help grow crops)