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PPT Slides of EVS by Mr. Ritesh Sharma
Faculty: Mr.Ritesh Sharma
Class: BBA Ist -B
10/6/2014
ENVIRONMENTAL STUDIES
MODULE-I
ENVIRONMENTAL STUDIES
WHAT IS ENVIRONMENT
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PPT Slides of EVS by Mr. Ritesh Sharma
Environment=System+Surroundings
Paryavaran= Pari+ Aawran
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ENVIRONMENT
 Our
Surrounding
sum total of all the conditions and influences
that affect the development and life of organisms.
organism lives in their own environment.
 For
us, Environment consists of Air, Water and
Land.
 Our
existence on the Earth is depend up on the
maintenance of symbiotic equilibrium with our
environment.
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PPT Slides of EVS by Mr. Ritesh Sharma
 Every
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 The
WHY STUDY ENVIRONMENT???
 Environmental
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studies deals with every issue
that affects a living organism.
is applied science, as it seeks practical
answers to the increasingly important question
of how to make human civilization sustainable
on the Earth’s resources.
 Integration
 Essential
Crisis”
PPT Slides of EVS by Mr. Ritesh Sharma
 It
of all the field of knowledge.
to study to overcome “Environmental
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BIOSPHERE
MAJOR COMPONENTS OF ENVIRONMENT
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Biosphere is the global sum of all ecosystems. It
refers to our environmental surroundings which
is the zone of life on earth. It includes:
• Atmosphere : Virtual Ocean of Air
• Hydrosphere: The surface of Earth filled with
any form of Water
• Lithosphere : Outer shell of the Earth
composed of crust and the rigid outer most
mantle
PPT Slides of EVS by Mr. Ritesh Sharma
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ATMOSPHERE
HYDROSPHERE
LITHOSPHERE
ENVIRONMENT DEFINITION
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PPT Slides of EVS by Mr. Ritesh Sharma
Environment can be defined as The external
elements and conditions
which surround, influence, and affect the
life and development of an organism or
population.
 The air, water, minerals, and all other
external factors which surround and affect
a given organism at any time.
 The social and cultural forces that shape
the life of a person or a population.
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PPT Slides of EVS by Mr. Ritesh Sharma
In general, environment can be
defined as, The Sum total of all
surroundings of a living organism,
including natural forces and other
living
things,
which
provide
conditions for development and
growth as well as for danger and
damage.
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ENVIRONMENTAL STUDIES
 It
is a field of study that systematically studies
human interaction with the environment. It is
understanding the functions of various
components of environment.
 It
deals with the analysis of the processes in water,
air, land, soil & organisms which lead to pollution
or environmental degradation. Thus, help us
understand the scientific basis for establishing
standards acceptably safe, clean & healthy for
man & natural ecosystem (animals, birds, aquatic
life, etc.)
MAJOR GOALS OF EVS
 To
improve the quality of Environment
 To create an awareness among the people on
environmental problems and conservation
 To create an atmosphere so that people participate
in decision making and develop the capabilities to
evaluate the developmental programmes
SCOPE OF EVS
 Day-
to- day interaction with the surroundings
with which human being is closely associated
 Related to many branches of science
 Concerned with the importance of wild life & its
protection
 Explains the significant role of biodiversity in
establishing ecological balance
 Deals with the different types of ecosystems,
biotic and abiotic factors and their role in the
significance and sustenance of ecosystems.
 Concerned
with different types of food chains,
food webs, productivity, biomass, carrying
capacity of ecosystems
 Gives
information relating to population
explosion, growth and development, impact of
population growth on the resource consumption
and national economy
 Explains the coexistence of both living and non
living organisms and their contribution to the
nature for its sustenance

Deals in relation to ethos and the impact of
ethical principles in the conservation of wild life,
biodiversity and environment
 Explains the significance of forests and their
products in the human routine and to country’s
economy
 Gives information about water conservation,
watershed management and the importance of
water
IMPORTANCE OF EVS
Environment issues being of international
importance
Problems cropped in the wake of development
Explosively increase in population
Need for an alternative solution
Need to save humanity from extinction
Need for wise planning of development
NATURAL RESOURCES
PPT Slides of EVS by Mr. Ritesh Sharma
For example:- forest, mineral deposit, or
fresh water that is found in nature and is
necessary or useful to humans.
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Natural resources are naturally occurring
substances that are considered valuable
in their relatively natural form.
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CLASSIFICATION OF NATURAL RESOURCES
 On
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PPT Slides of EVS by Mr. Ritesh Sharma
the basis of origin
Biotic (Organic):Biotic resources are obtained
from the biosphere, such as forests and their
products, animals, birds and their products, fish
and other marine organisms. Mineral fuels such
as coal and petroleum are also included in this
category because they formed from decayed
organic matter.
Abiotic (Inorganic):Abiotic resources include
non-living things. Examples include land, water,
air and ores such as gold, iron, copper, silver20
etc.
 Considering
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their stage of development
Potential: Potential resources are those that
exist in a region and may be used in the future.
For example, petroleum may exist in many
parts of India, having sedimentary rocks but
until the time it is actually drilled out and put
into use, it remains a potential resource.
Actual: Actual Resources are those that
have been surveyed, their quantity and quality
determined and are being used in present
times. For ex, Wood from forest
PPT Slides of EVS by Mr. Ritesh Sharma
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 With
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PPT Slides of EVS by Mr. Ritesh Sharma
respect of renewability
Renewable:
or
inexhaustible
natural
resources are ones that can be restocked or
reproduced easily. Some of them, like sunlight,
air, wind, etc., are continuously available and
their quantity is not affected by human
consumption.
Non-renewable: or Exhaustible natural
resources are formed over very long geological
periods. Minerals and fossil fuels are included in
this category. Since their rate of formation is
extremely slow, they cannot be replenished once
they get depleted
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 On
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PPT Slides of EVS by Mr. Ritesh Sharma
the basis of utility
Food
resources:
Fruits,
Vegetables, Pulses etc.
Energy resources: Sunlight, Air,
Water etc.
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FOREST RESOURCES
 Forests
are the most important resource of our
globe.
 The
PPT Slides of EVS by Mr. Ritesh Sharma
are found in each parts of globe - where
the factors of plant growth have been ideal for
several centuries. For this reason, they are
mostly found in regions of high rainfall and
regions of high altitude.
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 forests
usefulness of forests is spread to commercial
exploitation of forest for timber and other
products, maintenance of birds and wildlife,
maintenance of ecological balance, prevention of24
soil erosion, etc.
USES OF FORESTS
 Fuel-wood
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For the rural population, wood is an important source of
energy for cooking and heating. They prefer smaller
stems as these are easier to collect and carry. Some
of the wood is converted to charcoal and used for
cooking.
 Fodder
Fodder from the forest ,forms an important source for
cattle and other grazing animals in the hilly and the
dry regions and during a drought. There are many
varieties of grasses, trees, and shrubs that are
nutritious for the livestock. Care is taken to see that
trees poisonous to cattle are not grown. Cont…
PPT Slides of EVS by Mr. Ritesh Sharma
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 Fencing
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PPT Slides of EVS by Mr. Ritesh Sharma
Fences created with trees and shrubs are
preferred in developing countries as they are
cheap to maintain yet give protection. Species
that have thorns or are prickly and have stiff
branches and leaves which are not edible are
preferred.
 Wind breaks and shelter belts
Trees grown for wind breaks should be thick and
strong to withstand in both hot and cold strong
winds.
Cont….
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 Soil
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PPT Slides of EVS by Mr. Ritesh Sharma
erosion check
Tree roots bind the soil and prevent erosion
caused by wind or water. Leaf fall also provides
a soil cover that further protects the soil
 Soil improvement
Some species of trees have the ability to return
nitrogen to the soil through root decomposition
or fallen leaves. Such trees are planted to
increase the nitrogen content of the soil. Eg.
growing of tea and coffee
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FOREST PRODUCTS AND THEIR USES
 Timber:
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More than 1500 species of trees are
commercially exploited for timber in different parts
of India. It is used in timber-based industries such
as plywood; paper and pulp, and particle boards.
 Cane: Cane or rattan are the stems of a climber
plant and are used for a large number of
household items. It is used to make walking sticks,
polo sticks, baskets, picture frames, screens, and
mats.
 Grasses: There are hundreds of varieties of
grasses in the country that are used for a number
of purposes. Lemon grass, palm rose grass, and
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khus grass etc.
Cont….
PPT Slides of EVS by Mr. Ritesh Sharma
Bamboo: These are common in the north-eastern and
the south-western parts of India, growing along with
deciduous or evergreen forest. The main commercial
uses of bamboo are as timber substitutes, fodder, and
raw material for basket, paper and pulp, and other smallscale industries.
 Fruit: Fruit trees are an important source of income and
food for the rural household. In some areas fruit trees
are commonly planted along the field borders and
around the wells. Mango, coconut, orange, pear, jackfruit
and many others grow wild in the forest.
 Medicinal use: Even today man is dependent on the
forest for herbs and plants to fight against disease. Of all
the medicinal trees found in India, the neem is the most
important. Leaves, bark, and other parts of many other
trees also have medicinal value and are used to make
various
herbal
medicines.
Cont……

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PPT Slides of EVS by Mr. Ritesh Sharma
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 Fibre:
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Plant fibre has many different uses. Soft
fibres such as jute are derived from the stems of
the plant. Hard fibre from the leaves of hemp and
sisal are used to make fabrics for various
applications. Coir, another form of fibre from the
fruit of the coconut, is used to make ropes
 Floss: The fruits of many species of Indian trees
produce silky floss. The most common of these is
simal. It is used to made cotton wool, mattresses,
and pillows.
 Essential oils: Oil is distilled from the wood of
various species such as sandalwood, agar, and
pine. Oil is also derived from the leaves of certain
plants and trees such as eucalyptus, camphor,
wintergreen, and pine. These oils are used for
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making
soaps,
cosmetics,
incense,
pharmaceuticals, and confectionery.
PPT Slides of EVS by Mr. Ritesh Sharma
OVER EXPLOITATION OF FOREST RESOURCES
 The
term can be applied to various
natural resources such as medicinal
plants, grazing fields , fish stocks,
forests and even water.
PPT Slides of EVS by Mr. Ritesh Sharma
is also called as over
harvesting of natural resources
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 Overexploitation
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REASONS FOR OVER EXPLOITATION OF FOREST
RESOURCES
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PPT Slides of EVS by Mr. Ritesh Sharma
Excessive use of  Timber ,fuel wood and charcoal.
 Expansion of urban, agricultural and industrial
areas. (real-estate dev.)
 Wood for making houses.
 The fluctuations in the oil prices made many
rural communities to use biomass and wood as
source of fuel which again led to deforestation.
 Due to ever growing population in developing
countries needs more land. So they started
cutting down forests for clear land.
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Cont…….
 Demand
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PPT Slides of EVS by Mr. Ritesh Sharma
for food in highly populated countries is
very high. To fulfill this, many forest areas are
cleared for cultivation and other farming activities.
 During many military operations for killing enemies
forests are cleared in order to see people more
clearly prior to killing.
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DEFORESTATION
DEFORESTATION
 It
PPT Slides of EVS by Mr. Ritesh Sharma
is the clearance of forests
by cutting down and/or burning of
forests.
 Or in other words, It is The reckless
demolition of plants and trees. It is the
cutting down of forests for commercial use
without planting new one in lieu their of.
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 Deforestation
is the result of over exploitation of forest 35
resource.
CAUSES OF DEFORESTATION
 Fuel
PPT Slides of EVS by Mr. Ritesh Sharma
Cont….
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requirements: Increasing demands for fuel
wood by the growing population in India.
 Raw materials for industrial use: Wood for
making boxes, furniture, railway-sleepers,
plywood, match boxes, pulp for paper industry
etc. have exerted tremendous pressure on
forests.
 Development projects: Massive destruction of
forests occur for various development projects
like hydroelectric projects, big dams, road
construction, mining etc.
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 Growing
PPT Slides of EVS by Mr. Ritesh Sharma
Clearing forests for oil and mining exploitation;
to make highways and roads;
slash and burn farming techniques; wildfires; and
acid rain.
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food needs: In developing countries
this is the main reason for deforestation. To
meet the demands of rapidly growing
population, agricultural lands and settlements
are created permanently by clearing forests.
Some other reasons are:
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EFFECTS OF DEFORESTATION
Erosion of Soil
 When forest areas are cleared, it results in exposing the
soil to the sun, making it very dry and eventually,
infertile, due to volatile nutrients such as nitrogen being
lost.
 when there is rainfall, it washes away the rest of the
nutrients, which flow with the rainwater into waterways
 Due to above reasons, replanting trees may not help in
solving the problems caused by deforestation, because
by the time the trees get mature, the soil will be totally
devoid of essential nutrients.
 Ultimately, cultivation in this land will also become
impossible, resulting in the land becoming useless.
Cont……. 38
PPT Slides of EVS by Mr. Ritesh Sharma
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Disruption of the Water Cycle
 Trees contribute in a large way in maintaining the
water cycle.
 They draw up water via their roots, which are then
released into the atmosphere.
 When these trees are cut down it results in the
climate getting drier in that area.
Flooding and Drought
 One of the vital functions of forests is to absorb
and store great amounts of water quickly when
there are heavy rains.
 When forests are cut down, this regulation of the
flow of water is disrupted, which leads to
alternating periods of flood and then drought in the
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affected area.
Cont….
PPT Slides of EVS by Mr. Ritesh Sharma
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Climate Change
 Global warming is being caused largely due to
emissions of greenhouse gases like carbon dioxide
into the atmosphere. Deforestation has a direction
association with carbon dioxide emissions into the
atmosphere. Trees act as a major storage depot
for carbon, since they absorb carbon dioxide from
the atmosphere, which is then used to produce
carbohydrates, fats, and proteins that make up
trees.
 When deforestation occurs, many of the trees are
burnt or they are allowed to decay, which results in
releasing the carbon that is stored in them as
carbon dioxide. This, in turn, leads to greater
concentrations of carbon dioxide in to the
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atmosphere.
Cont….
PPT Slides of EVS by Mr. Ritesh Sharma
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Miscellaneous reasons
 It threatens the existence of many wild life species
due to destruction of their natural habitat.
 In hilly areas it often leads to landslides.
PPT Slides of EVS by Mr. Ritesh Sharma
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TIMBER EXTRACTION
TIMBER EXTRACTION
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PPT Slides of EVS by Mr. Ritesh Sharma
Extraction of timber from the forests is desired
only to some extent. It is desired till it does
not fall in the category of deforestation. But
its excessive extraction has detrimental
effects on forests as well as on the life style
of tribal people living in its region. Amongst
these, the major ill-effects are the same as
found in deforestation.
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MINING
MINING
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PPT Slides of EVS by Mr. Ritesh Sharma
Mining refers to the process of extracting metals
and minerals from the earth. Gold, silver,
diamond, iron, coal and uranium are just a few of
the vast array of metals and minerals that are
obtained by this process.
 Mining is the source of all the substances that
cannot be obtained by industrial processes or
through agriculture.
 Mining reaps huge profits for the companies that
own them and provides employment to a large
number of people.
 It is also a huge source of revenue for the
government.
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PPT Slides of EVS by Mr. Ritesh Sharma
EFFECTS OF MINING ON ENVIRONMENT
Effect on Land
 Deforestation: Mining requires large areas of land
to be cleared so that the earth could be dug into by
the miners. For this reason, large scale
deforestation is required. Besides clearing the
mining area, vegetation in the adjoining areas also
needs to be cut in order to construct roads and
residential facilities for the mine workers. The
human population brings along with it other
activities that harm the environment.
 Pollution: Despite measures being taken to
release the chemical waste into the nearby rivers
through pipes, a large amount of chemicals still
leak out onto the land. This changes the chemical
composition of the land. Cont……
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Effect on Water
 Pollution: Chemicals like mercury, cyanide, sulfuric acid,
arsenic and methyl mercury are used in various stages of
mining. Most of the chemicals are released into nearby
water bodies that lead to water pollution. In spite of tailings
(pipes) being used to dispose these chemicals into the
water bodies, possibilities of leakage are always there.
When the leaked chemicals slowly penetrate through the
layers of the earth, they reach the groundwater and pollute
it.
 Loss of Aquatic Life: Release of toxic chemicals into the
water is obviously harmful for the plants and animals of the
water. Besides the pollution, mining processes use water
from nearby water sources. The result is that the water
content of the river or lake from which water is being used
gets reduced. Organisms in these water bodies do not have47
enough water for their survival.
PPT Slides of EVS by Mr. Ritesh Sharma
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PPT Slides of EVS by Mr. Ritesh Sharma
Spread of Diseases:
 Sometimes the liquid waste that is generated
after the metals or a mineral has been extracted
is disposed in a mining pit. As the pit gets filled
up by the mine tailings, they become a stagnant
pool of water. This becomes the breeding
ground for water-borne diseases causing
insects and organisms like mosquitoes to
flourish.
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DAMS
DAM
A
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dam is a barrier that impounds water or
underground streams.
 Dams generally serve the primary purpose of
retaining water, while other structures such as
floodgates are used to manage or prevent water
flow into specific land regions.
 A dam can also be used to collect water or for
storage of water which can be evenly
distributed between locations.
PPT Slides of EVS by Mr. Ritesh Sharma
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ADVANTAGES OF DAM
Flood control during heavy rain and water accumulating
season. Without the dams flooding may result in the
downstream of the river mostly in the plains.
 During heavy rainy season water just goes to the sea
without benefiting anyone. Dams prevent, it and the water
is used later beneficially.
 Power can be produced without any pollution.
 Controlled irrigation can be done which will allow the
farmer to sow and harvest in time without depending on
rain too much.
 Neighboring cities gets good water throughout the year.
 Employment for the power station people and agriculturist
etc.
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
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DISADVANTAGES OF DAM
 When
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Dams are built government does not really
take care of the villagers in that area, which will
be affected by the construction. Many villages will
be gone under the dam.
 Construction activities can harm the environment
by causing noise and pollution.
 If proper care is not taken then mud from the
flowing rivers get accumulated in the dams and
the capacity of the dams gets reduced in course
of time.
PPT Slides of EVS by Mr. Ritesh Sharma
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WATER RESOURCES
 Water
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resources are sources of water that are
useful or potentially useful to humans.
 Uses of water include agricultural, industrial,
household, recreational and environmental
activities.
 Virtually all human uses & require fresh water
for their survival.
 97% of water on the Earth is salt water, and only
3% as fresh water of which slightly over two
thirds is frozen in glaciers and polar ice caps.
The remaining unfrozen fresh water is mainly
found as groundwater, with only a small fraction
present above ground or in the air.
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FACTORS AFFECTING WATER RESOURCES
 Climatic
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factors
Rainfall: its intensity, duration & distribution.
Snow
Evapo-transpiration
 Physiographic factors
Basic characteristics.
Geometric factors: drainage area, shape, slope
& stream density.
Physical factors: land use, surface penetration
conditions, soil types, etc.
Channel characteristics: carrying capacity 54&
storage capacity.
PPT Slides of EVS by Mr. Ritesh Sharma
MINERAL RESOURCES
 Minerals
Elements that occur naturally are also considered
minerals.
 Minerals
are economic commodity; they are mined
because of the need for a valuable element they
contain or an inherent property they have.
PPT Slides of EVS by Mr. Ritesh Sharma

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are naturally occurring, inorganic,
crystalline solids having definite chemical
composition and characteristic physical properties.
There are thousands of minerals occurring in
different parts of the world.
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 Some
minerals are mined for their beauty and
rareness, thus giving many specimens (Tajmahalmarble) which have accepted worldwide value.
PPT Slides of EVS by Mr. Ritesh Sharma
are generally used for- development of
industrial
plants,
generation
of
energy,
construction, equipments and arms for defense,
transportation
means,
medical
system,
communication, jewellery- gold, silver etc.
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 Minerals
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FOOD RESOURCES
 There
The main food resources include wheat, rice,
maize, potato, barley, etc. about twenty or so
common fruits and vegetables, milk, meat, fish
and seafood etc.
PPT Slides of EVS by Mr. Ritesh Sharma

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are thousands of edible plants and animals
on the earth out of which only about three dozen
types constitute major food of humans.
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WORLD FOOD PROBLEMS
 Every
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year food problem is killing as many people
as were killed by the atomic bomb dropped on
Hiroshima during World War II.
 This shows that there is drastic need to increase
food production, equitably distribute it and also to
control population growth.
 Although India is the third largest producer of
crops, an estimated 300 million Indians are still
undernourished.
 India has only half as much land as USA, but it
has nearly three times population to feed. Our
food problems are directly related to population. 58
PPT Slides of EVS by Mr. Ritesh Sharma
ENERGY RESOURCES
 Energy
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consumption and production of a nation is
usually considered a guide of its development.
 This is because almost all the development
activities are directly or indirectly dependent upon
energy.
 The most original form of energy technology
probably was the fire, which produced heat and
the early man used it for cooking and heating
purposes. Wind and hydropower has also been
used.
 Invention of steam engines replaced the burning
of wood by coal and gradually coal was further
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replaced by oil.
PPT Slides of EVS by Mr. Ritesh Sharma
TYPES OF ENERGY RESOURCES
Renewable (Solar energy,wind energy etc.) and
 Non-renewable Energy resources.(coal, petroleum,
natural gas, nuclear energy)
Renewable energy resources must be preferred over the
non-renewable resources. This will try to end the energy
crisis which the world is facing today. It is inevitable truth
that now there is an urgent need of thinking about
alternative sources of energy, which are also termed as
non-conventional energy sources which include:
 Solar energy- made up equipments such has solar heat
collectors, solar cells, solar cooker, solar water heater,
solar furnace, solar power plants.
 Wind energy
 Hydropower, biomass, biogas, bio-fuels etc.
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
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LAND RESOURCES
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Land as a Resource
 Land is a finite and valuable resource on which
we depend for our food, fiber and fuel wood, the
basic amenities of life.
PPT Slides of EVS by Mr. Ritesh Sharma
 Or
in other words, Land resources are the
resources of water, soils, forests, grazing land
and wildlife, on which agriculture, forestry and
other forms of rural land use depend. They are
destroyed by land degradation and conserved
by sustainable land management.
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erosion, water logging, and contamination of
the soil with industrial wastes like fly-ash, press
mud or heavy metals all cause degradation of
land.
PPT Slides of EVS by Mr. Ritesh Sharma
 Soil
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Land Degradation
 Because of increasing of population growth the
demands for land for producing food and fuel
wood is also increasing. Hence there is more and
more pressure on the limited land resources
which are getting degraded due to overexploitation.
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CONSERVATION OF NATURAL
RESOURCES: ROLE OF AN INDIVIDUAL
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PPT Slides of EVS by Mr. Ritesh Sharma
Different natural resources like forests, water,
soil, food, mineral and energy resources
play a vital role in the development of a
nation. With our small individual efforts we
can together help in conserving our natural
resources to a large extent.
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CONSERVATION OF WATER
 Don’t keep water taps running while brushing,
shaving, washing or bathing.
 In washing machines fill the machine only to the
level required for your clothes.
 Check for water leaks in pipes and toilets and
repair them promptly.
 Reuse the soapy water of washing from clothes for
gardening, driveways etc.
 Water the plants and the lawns in the evening
when evaporation losses are minimum. Never
water the plants in mid-day.
 Install a system to capture rain water (Rain
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Harvesting)
PPT Slides of EVS by Mr. Ritesh Sharma
CONSERVATION OF ENERGY
 Turn
off lights fans and other appliances when not in
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use.
 Obtain as much heat as possible from natural sources.
Dry the clothes in sun instead of direr if possible.
 Use solar cooker for cooking which will be more
nutritious and will save your LPG expenses.
 Build your house with provision for sunspace which
will keep your house warmer and will provide more
light.
 Drive less, make fewer trips and use public
transportations whenever possible. Share a car-pool if
possible.
 Control the use of A.C.
 Use bicycle or just walk down small distances instead
of using vehicle.
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PROTECT THE SOIL
 Grow
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different types of ornamental plants, herbs
and trees in your garden. Grow grass in the open
areas which will bind the soil and prevent its
erosion.
 Make compost from your kitchen waste and use it
for your kitchen-garden.
 Do not irrigate the plants using a strong flow of
water as it would wash off the soil.
 Better use sprinkling irrigation.
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THE ECOSYSTEM
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An ecosystem is a biological environment
consisting of all the organisms living in a
particular area, as well as all the non-living,
physical components of the environment with
which the organisms interact, such as air,
soil, water, and sunlight.
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Ecosystem
• Diverse and Dynamic by their size, structure and function
Ecosystem
Natural
Man made
Terrestrial
Forests
Deserts
Grass land
Mountain
Etc.
Aquatic
Agricultural field
FreshMarine Range land
water
Urban area
River
Garden, Dams
Etc.
Lake
STRUCTURE OF ECOSYSTEM
IMPORTANT CONCEPTS OF ECOLOGY
 Living
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organism: An organism is any form of life. A
wide range and variety of organisms is present on the
earth from the single celled amoeba to huge sharks,
from microscopic blue-green algae to massive banyan
tree. It includes all plants and animals.
 Species: Group of organisms that resemble one
another in appearance, behaviour, chemistry and
genetic structure form a species. Organisms of the
same species can breed with one another and produce
fertile offspring under natural conditions. For instance,
all human beings (Homo sapiens) resemble one
another in their body structure, body systems and they
all have similar genetic structure. They are thus
grouped together under the species sapiens. Cont…….
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 Population:
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A population is a group of
individuals of the same species occupying a
given area at a given time. For example, the
Asiatic lions in the Gir National Park, Gujarat,
make a population. Group of individual organisms
of the same species living within an area is called
population.
 Communities: Communities of various species
occupying a particular area and interacting
with each other make up a community. For
instance, when we say ‘the community of the Gir
National Park’, we refer to the lion population, the
deer population, the cattle population, the grass
population and populations of all kinds of life forms
present there. Thus community comprises several
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species interacting with each other.Cont…….
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 Cycles:
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The circulation of the chemical
elements in its biosphere from the
environment to organisms and back to the
environment is called cycle.
 Food chain: The transfer of food energy
from its source in plants through a series of
organisms where eating and being eaten is
repeated a number of times are called food
chain.
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MAJOR ECOSYSTEM INCLUDE
 Forest ecosystem- include tropical rain forests,
tropical deciduous forests, tropical scrub forests,
temperate rain forests, temperate deciduous
forests, evergreen coniferous forests.
 Grassland
ecosystemsinclude
tropical
grasslands,
temperate
grasslands,
polar
grasslands.
 Desert Ecosystems- include tropical deserts,
temperate deserts, cold deserts etc.
 Aquatic ecosystem- include pond ecosystem, lake
ecosystem, steams, oceans, estuary- a partially
enclosed coastal area at the mouth of a river
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where fresh water and salty seawater meet
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PRODUCERS, CONSUMERS AND DECOMPOSERS
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Producers: Photosynthesizing organisms. Producers are
any kind of green plant. Green plants make their food by
taking sunlight and using the energy to make sugar. The
plant uses this sugar, also called glucose to make many
things, such as wood, leaves, roots, and bark.
Consumers: Any organism that can’t make its own food.
Consumers have to depend upon producers to survive.
Deer are herbivores, which mean that they only eat
plants (Producers). Bears are another example of
consumers.
Decomposers: An organism that primarily feeds on dead
organisms or the waste from living organisms.
Decomposers are the garbage men of the animal
kingdom; they take all the dead animals and plants
(consumers and decomposers) and break them down
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into their nutrient components so that plants can use
them to make more food.
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FOOD CHAINS
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 Herbivores
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A food chain is an ecosystem is a chain of
organisms through which one organism
secures food by eating another organism.
gain energy by eating plants;
 Carnivores in turn gain energy by consuming
animals and
 the decomposers act upon the organic matter of
dead herbivores and carnivores and derive
energy.
Thus food from one tropic level reaches to the
other trophy level and in this way a chain is
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established. This is known as food chain.
DIAGRAM OF FOOD CHAIN
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TYPES OF FOOD CHAINS
There are two kinds of food chains –
 Grazing food chains
The grazing food chain begins with the
photosynthetic fixation of light, carbon dioxide, and
water by plants (primary producers) that produce
sugars and other organic molecules. Once
produced, these compounds can be used to create
the various types of plant tissues. Primary
consumers or herbivores form the second link in
the grazing food chain. They gain their energy by
consuming
primary
producers.
Secondary
consumers or primary carnivores, the third link in
the chain, gain their energy by consuming
herbivores. Tertiary consumers or secondary
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carnivores are animals that receive their organic
energy by consuming primary carnivores.
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DIAGRAM OF GRAZING FOOD CHAIN
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 Detritus
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food chain
Decomposers and detritivores obtain their
nutrients and energy from this resource as
opposed to the sun. All the organisms feeding
on the detritus are part of the detritus food
chain. Those feeding directly on the detritus are
primary detritus feeders and those preying on
these organisms are secondary detritus feeders
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DIAGRAM OF DETRITUS FOOD CHAIN
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CHARACTERISTICS OF FOOD CHAIN
 There
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is repeated eating in which each group
eats the smaller one and is eaten by the larger
one.
 The
plants and animals which depend
successively on one another form the members
of a food chain.
 There is unidirectional flow of energy from sun
to producers and then to a series of consumers
of various types. Thus, a food chain is always
straight and proceeds in a progressing straight
line.
Cont…
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 Usually
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80 to 90% of potential energy is lost as
heat at each transfer on the basis of second
law of thermodynamics (transformation of
energy involves loss of unavailable energy).
 Usually there are 4 or 5 tropic levels. Shorter
food chains provide greater available energy
and vice - versa.
 Omnivores occupy more than one tropic level
and, some organisms occupy different tropic
positions in different food chains.
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FOOD WEBS
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Food web can be defined as, "a network of
food chains which are interconnected at
various tropic levels, so as to form a
number of feeding connections amongst
different
organisms
of
a
biotic
community".
Or in other words, The inter-connected food
chains operating in an ecosystem which
establish a network of relationships
between various species, is called a food
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web.
DIAGRAM OF FOOD WEB IN GRASSLAND
ECOSYSTEM
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DIAGRAM OF FOOD WEB IN FOREST
ECOSYSTEM
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TROPIC LEVELS
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The various links or steps in a food chain at which the
transfer of food or energy takes place are called
tropic levels.
In a food chain, each link representing an organism is a
tropic level.
Types and Examples
 FIRST TROPHIC LEVEL
plants which are producers
 SECOND TROPHIC LEVEL
herbivores
 THIRD TROPHIC LEVEL
carnivores
 FOURTH TROPHIC LEVEL
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Large or top carnivores
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ENERGY FLOW IN THE ECOSYSTEM
 Every
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ecosystem requires energy for its
survival. The supply of energy has to be
continuous to maintain the biotic structures
and their functions.
 In biosphere sun is the ultimate source of
energy .
 Energy is not created in the atmosphere. It
is only converted from one form to another.
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FLOW OF ENERGY
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It happens in three steps:Step I-The green plants (Producers) trap solar energy
through the process of photosynthesis. They, than
convert solar energy into chemical energy which is
stored as carbohydrates in the plants. The plants utilize
this energy as for their metabolic activities like
respiration and growth. Some energy which is not
utilized ,get released as unusable heat into the
community environment.
Step II-The plants are eaten up by herbivores. The
chemical energy stored in plants is transferred with
food to herbivores. They also utilize this energy for their
metabolic activities like respiration and growth. Some
energy which is not utilized ,get released as unusable
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heat into the community environment.
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Step III-The
herbivores are eaten up by
Carnivores. The chemical energy stored in
flesh of herbivores transferred with food to
Carnivores. They also utilize this energy for
their metabolic activities like respiration and
growth. Some energy which is not utilized ,get
released as unusable heat into the community
environment.
This process of transfer of energy is repeated
with large carnivores who eat small carnivores
and so on. Some of the energy from plants
and animals is utilized for the life processes by
decomposers, who in turn release the
unutilized energy as heat into the environment90.
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ECOLOGICAL SUCCESSION
It can be defined as, the process of ecological
development which involves gradual and
successive replacement of one population
(community) by the other.
It is of two types:
-Primary- First time on the bare land. May be
after volcanic explosion from the lava and
favorable atmosphere.
-Secondary- Secondary succession is far
more common. It occurs in an area where life
once existed but has then been destroyed due
to some ecological disturbance such as forest
fire, tsunami, flood etc., and after some time
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plants begins to reappear.
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KINDS OF ECOLOGICAL SUCCESSION
 These
-
Xerarch- The succession taking place in
the dry terrestrial area. It is further divided
into-
Lithosphere-On the rocks
Psammosere- On the sandy habitat.
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Hydrosere that is in ponds and lakes
- Halosere in ocean, river and sea.
-
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-
are two kinds:
Hydrarch-The succession occurring in
water bodies like pond and lakes. It is
further divided into-
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STAGES OF ECOLOGICAL SUCCESSION
 Pioneer
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Stage- The plants that invade the bare
land are called as pioneer species. They show high
rate of growth and short span.
 Seral Stage-This is the time or stage in which the
pioneer community is replaced by the another
community, which is yet by another community, and
so on.
 Climax Stage- The plant species which get
established later, during the course of succession
are known as late succession species. These
species are slow growing and long lived. The
terminal stage of succession is represented by
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climax community. It is stable and doesn't show
changes as long as environmental conditions
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ECOLOGICAL PYRAMIDS
An ecological pyramid is a graphical
representation designed to show the number
of organisms, energy relationships, and
biomass of an ecosystem.
They are also called Eltonian pyramids after
Charles Elton, who developed the concept of
ecological pyramids.
In simple words, Ecological pyramids are
graphical representations of the number of
individuals in different nutritional levels.
In other words, it is a way of representing
energy transfer taking place in a food chain .
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DIFFERENT STAGES OF ECOLOGICAL PYRAMIDS
 Base
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represents the producer which is the Ist
tropic level.
 Lower tier depicts primary consumer which is
IInd tropic level.
 Higher tier depicts the secondary consumer
which is IIIrd tropic level.
 Apex depicts tertiary consumer which is IVth
tropic level.
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TYPES OF ECOLOGICAL PYRAMIDS
 Pyramids
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of number: Pyramids of number allow
us to compare the number of organisms present
in each tropic level at a particular time. It is
expressed in numbers per unit area.
 Generally,
this pyramid is upright. E.g.Grassland, Pond ecosystem etc. Here the
producers are always maximum in number.
 Numbers than show a decrease towards the
apex , as the primary consumers are lesser in
number than producers, the secondary
consumers are lesser in number than the primary
consumers. Finally, the top carnivores are least
in number. Thus the pyramid becomes upright. 99
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In
thousands
100
In
Lakh
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In
Hundreds
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Very Few
More
Carnivores
Herbivores
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Less
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However, in certain cases, this pyramid is
somewhat different in shape.. E.g. in forest
ecosystem, the producers are mainly large sized
trees and are lesser in number than herbivores(
fruit eating birds, deer, elephant etc.). Then
there is a gradual decrease in the number of
successive carnivores making it upright once
again.
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Very Few
Producers

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Pyramids of biomass: Biomass is a measure of the total
amount or mass all the living organism present at each tropic
level. Pyramids of biomass allow us to compare the mass of
organisms present in each tropic level at a particular time.
Generally, it is upright and expressed in gram/unit area. E.g.
Pyramid of biomass for terrestrial ecosystem will always be
upright.
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However in some cases ,it is inverted. E.g. deep water
bodies, producers are small organism, their biomass is
least and this quantity gradually shows an increase
towards the apex of the pyramid.
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
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Decrease in energy
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Pyramids of energy: Pyramids of energy allow us to
compare the amount of energy passing through each
tropic level over a period of time. It is expressed in
calories/ unit area/year. Pyramids of energy are always
pyramid-shaped that is always upright . There are no
exceptions to this rule.
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