Environmental Science Reviewer
The science of Environment studies is a
multi-disciplinary science because it comprises
various branches of studies like chemistry, physics,
medical science, life science, agriculture, public
health, sanitary engineering etc.
Definition of Environment:
‘A person’s environment consists of the sum total of
the stimulation which he receives from his
conception until his death.’- Boring
‘‘The term environment is used to describe, in the
aggregate, all the external forces, influences and
conditions, which affect the life, nature, behavior
and the growth, development and maturity of living
organisms.’ - Douglas and Holland
SEGMENTS OF ENVIRONMENT
Atmosphere
The atmosphere implies the protective blanket of
gases, surrounding the earth. Atmosphere is
composed of 78% Nitrogen, 21% Oxygen, and 1%
other gases.
Hydrosphere
The hydrosphere comprises of all types of water
resources: oceans, seas, lakes, rivers, stream,
reservoir, polar icecaps, glaciers, and ground water.
Earth’s water supply
97% - is in the ocean
2% - is locked in the polar icecaps and glaciers
1% - is available as fresh surface water
Lithosphere
Lithosphere is the outer mantle of the solid
earth. It consists of minerals occurring in the
earth's crusts and the soil e.g., mineral, and
organic matter.
Biosphere
Biosphere indicates the realm of living organisms
and their interactions with environment, viz
atmosphere, hydrosphere and lithosphere.
ELEMENTS OF THE ENVIRONMENT
1. Physical elements - are as space, landforms, water
bodies, climate soils, rocks and minerals.
2. Biological elements - such as plants, animals,
microorganisms and men constitute the biosphere.
3. Cultural elements - such as economic, social and
political elements are essentially man-made
features.
MODULE 1- Humans and Sustainability.
Environmental Problems
Pollution: is the introduction of harmful materials
into the environment. These harmful materials are
called pollutants. Pollutants damage the quality of
air, water, and land.
Global Warming: The emission of greenhouse gases
due to human activity causes global warming, which
in turn causes an increase in temperature that then
leads to rising sea levels, melting of polar ice caps,
flash floods and desertification.
Growing Population: It puts considerable pressure
on its natural resources and reduces the gains of
development. The greatest challenge before us is to
limit the population growth.
Waste Disposal: An excessive amount of waste is
produced and dumped in the rivers, oceans and
lands.
Ocean Acidification: The increase in the production
of carbon dioxide by humans causes the oceans’
acidity to rise, which has a negative impact on
marine life.
Loss of Biodiversity: Species and habitats are
becoming extinct due to human activity. This causes
an imbalance in natural processes like pollination
and poses a threat to ecosystems – coral reef
destruction is particularly affected.
Deforestation: Deforestation refers to the decrease
in forest areas across the world that are lost for
other uses such as agricultural croplands,
urbanization, or mining activities. Loss of trees in
order to make space for residential, industrial or
commercial projects means that less oxygen is
produced, and temperature and rainfall are affected.
Ozone Layer Depletion: Pollution caused by
chlorofluorocarbons (CFCs) in the air creates a hole
