1. Environment,
Ecology and Ecosystem
Environmental Science
UNIT-1

2. Environment
• Environmental science is an interdisciplinary field that
includes both scientific and social aspects of human
impact on the world.
• The word environment is usually understood to mean the
surrounding conditions that affect organisms.
• In a broader definition, environment is everything that
affects an organism during its lifetime.
• In turn, all organisms including people affect many
components in their environment

3. Environmental Science
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4. Classification of Environment
2

5. Components of Environment
• The two major Components of environment are :
Abiotic components : Air, Water, and Land etc
Biotic components: All living organisms around us viz. plants, animals,
and microorganisms
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6. Components of Environment
• Earth’s environment can be further
subdivided into the following four
segments:
(1) Atmosphere
(2) Lithosphere
(3) Hydrosphere
(4) Biosphere
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7. Atmosphere
 It is the gaseous envelope surrounding the earth and
extends upto 500 kms above the earth’s surface.
Constituent Volume %
– Nitrogen 78.1
– Oxygen 20.9
– Water vapour 0.1–5
– Argon 0.9
– Carbon dioxide 0.03
– Trace constituents* Balance
– *The trace constituents include Helium, Neon,
Krypton, xenon, SO2, NO2, Ammonia, Ozone, and
– Carbon monoxide etc.
 The atmosphere, which is a gaseous cover, protects
the earth from cosmic radiations and provides life
sustaining Oxygen, the macronutrient Nitrogen and
Carbon dioxide needed for photosynthesis.
 The atmosphere screens the dangerous UV radiations
from the sun and allows only radiations in the range of
300 nm – 2500 nm (near UV to near IR) and radio
waves.
 The atmosphere plays a major role in maintaining the
heat balance of the earth by absorbing there-emitted
radiation from the earth.
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6

8. Five Layers of the Atmosphere
Troposphere : lowest layer – extends up to 10km; contains 99% of the water
vapor and 75% of the atmospheric gases
• The troposphere is the first layer above the surface and contains most
clouds and half of the Earth's atmosphere.
• Weather occurs in this layer
Stratosphere – directly above troposphere, extending from 10 km to about 50 km
above Earth’s surface
• Portion of the upper layer contains high levels of a gas called ozone
• Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone
layer absorbs
harmful rays from the Sun
Mesosphere – extends from the top of the stratosphere to about 85 km above
Earth
• Coldest layer with little ozone
• Meteors or rock fragments burn up in the mesosphere.
• Ionosphere here – layer of charged particles

9. Thermosphere – thickest atmospheric layer found between 85 km and 500 km above
Earth’s surface
• The thermosphere is a layer with auroras, known for its high temperatures.
Warms as it filters out X-rays and gamma rays from the Sun
Ionosphere here, too – help carry radio waves
Exosphere - The atmosphere merges into space in the extremely thin
exosphere. This is the upper limit of our atmosphere.
• Outer layer where space shuttle orbits.

10. Lithosphere
• The earth’s crust consisting of the soil
and rocks is the lithosphere. The soil is
made up of inorganic and organic
matter and water.
• The main mineral constituents are
compounds or mixtures derived from
the elements of Si, Ca, K, Al, Fe, Mn, Ti,
O etc. (Oxides, Silicates, and
Carbonates).
• The organic constituents are mainly
polysaccharides, organo compounds of
N, P and S.
• The organic constituents even though
form only around 4% – 6% of the
lithosphere, they are responsible for
the fertility of the soil and hence its
productivity
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8

11. Hydrosphere
 This comprises all water resources both surface
and ground water.
 The world’s water is found in oceans and seas,
lakes and reservoirs, rivers and streams, the
Polar Regions in addition to ground water below
the land areas. The distribution of water
 among these resources is as under
– Oceans and Seas 96–97 %
– Glaciers and polar icecaps 2–3 %
– Fresh water < 1%
 The water locked up in the Oceans and Seas are
too salty and cannot be used directly for human
consumption, domestic, agriculture or Industrial
purposes.
 Only less than 1% of water resources are
available for human exploitation. Water is
considered to be a common compound with
uncommon properties. These uncommon
properties (e.g. anomalous expansion of water)
are mainly responsible for supporting terrestrial
and aquatic life on earth.
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10

12. Biosphere
• The biosphere is a capsule encircling the
earth’s surface wherein all the living
things exist.
• This portion extends from 10000 m below
sea level to 6000 m above sea level.
• Life forms do not exist outside this zone.
• The biosphere covers parts of other
segments of the environment viz.
Lithosphere, Hydrosphere and
Atmosphere.
• Life sustaining resources like food, water
and
oxygen present in the biosphere are
being withdrawn and waste products in
increasing quantities are being dumped. 11

13. Types of Environment
• Natural Environment
– The environment that comes in its
existence by its own or naturally.
– Without interference of humans
– It operates through self regulating
mechanism(Homeostasis)
• Man-made
Environment(Anthropogenic)
– Env. Is modified by human activity
– Scientific technology which is
result of human brain is decorating
the natural environment.
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14. Objective of Environmental education
• Awareness:
• Knowledge
• Attitudes
• Skills
• Participation

15. Importance of Environmental science
• Solving the issues related to environment
– Pollution
– Over exploitation of non-renewable sources
– Food problem
– Sustainable development
– Maintain the ecological balance
– Eco friendly product
– Conservation of natural sources
– Understand the food chain
– Inculcating attitude and value
– Encouraging Environment protection

16. Scope of Environmental Science
• Natural Resources
• Ecology
• Biodiversity and its conservation
• Environment pollution and control
• Natural disaster
• Development
• Social issues in relation to development and
environment
• Human population and environment
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17. Learning to Live More Sustainably

18. Man and Environment
• Natural Conservations
– Sacred Groves of India
– Water storage : Water reservoir
• Traditional methods of Agricultures
• Traditional Methods of fishing
• Ecosystem Balance

19. Traditional Man and environment relationship
Sacred Groves of India
• Traditional uses:
– Ayurvedic medicines.
– Replenish able resources like fruits and honey.
– The vegetation cover helps reduce soil erosion and
prevents desertification,
– Water requirements of local communities.
• Modern uses:
– biodiversity hotspots,
– Sacred groves often contain plant and animal species
that have become extinct in neighboring areas.
– sacred groves in urban landscapes act as "lungs" to
the city as well, providing much needed vegetation
cover.
• Threats
– Urbanization, over-exploitation of resources
– Environmental destruction due to religious practices.
– Other threats to the sacred groves include invasion.
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20. Traditional Method of Farming
• Traditional Use
– Planting were coordinated with the
movement of plant and stars
– Harmony with the local Environment and
Seasons
– Cultivate large no of Crops varieties.
– Rotation of crop and Soil fertility
– Mixing sand, Slit and clay in right
proportion.
• Modern Use
– Heavy use of chemical and pesticides
– Local biodiversity affected
– Use of Vehicles.
• Treats
– Food security
– GMO Food
– Pesticides 15

21. Traditional method of fishing
• Traditional
– Fishers have extensive knowledge of
oceans and fisheries
– Mesh size of the nets was designed to
catch only a particular species, and
among them only the adult fish
• Modern
– Mechanized boats and later big trawlers.
– Outsiders entered in the business with the
aim of cating as much fish as possible
• Threats
– No regards for conservation of resource.
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22. Impact of Science and technology on the
environment
• Invention of Engines and Automobiles
• Efficient machines were made for sawing and felling
trees.
• Cutting down the trees
• Invention of concrete building of dams, and diversion of
rivers water for agriculture and power production
• Chemical fertilizer and pesticides
• Huge amount of ground water is extracted with pumps

23. Environmental Degradation
What is environmental degradation? Let us understand it.
 It is the process by which our environment i.e., air, water
and land, is progressively contaminated, over- exploited and
destroyed.
 When the environment becomes less valuable or damaged,
environmental degradation is said to occur.
 In specific term, environmental degradation is the
deterioration of the environment through depletion of
resources such as air, water, soil and forest; the destruction
of eco-systems and the extinction of wildlife.

24. Causes of Environmental Degradation
Social factors
 Growing Population
 Poverty
 Urbanization
 Changing life style
Economic factors
 Agricultural Development
 Industrialization
 Economic Development

25. Growing Population
 Population is the greatest resource of any country and a
major contributory factor for development, and yet it is a major
cause of environmental degradation.
 As we find, the rapid pace of population growth has led to the
excessive utilization of natural resources.
 Huge population also leads to huge production of wastes.
 The resultant outcomes are loss of biodiversity, pollution of
air, water and soil and increased pressure on arable land. All
these have been putting great stress on the environment.

26. Poverty
 Poverty is said to be both the cause and effect of
environmental degradation.
 You may have seen that the poor people use natural
resources more than the rich.
 They use these for building their huts, for cooking, for their
food and for meeting many other needs.
 In this way they deplete these resources faster as they have
no opportunity of gaining access to other types of resources
that are primarily exploited by the rich.
 As we know, the more the resources are utilized, the more
degraded the environment becomes.
 The more the environment deteriorates, the more
impoverished the poor will be.

27. Urbanization
 You may have observed a large number of poor people from
villages moving to towns, cities and mega cities to earn their
livelihood. This has led to unplanned and rapid expansion of
cities, creating enormous pressure on the infrastructural
facilities.
 If you live in a city, you may be experiencing these pressures
on housing, water and electric supply and sewage.
 You would be aware of the growing slums.
 Urban slums are major sources of pollution and suffer from
the worst kind of unhygienic conditions.
 The fast pace of urbanization has also been responsible for
the depletion of forests and irrational use of other resources.

28. Changing Life Style
 There has been a remarkable change in the style of living of people.
 This change is visible not only among the people living in cities and
towns but also among those who live in villages.
 The changing life style of people has enormously increased their level
of consumption.
 It has also resulted in the increase of human activities that are
causing serious damage to environment in many ways.
 It has contributed to air, water, sound, vehicular and industrial
pollution.
 The fallout of the fast increasing use of modern gadgets like
refrigerators and air conditioners is the release of harmful gases in the
atmosphere.
 This has been causing global warming which is very dangerous. In
fact, due to overuse of modern gadgets, harmful gases like carbon
monoxide and carbon dioxide
are released which lead to global warming

29. Agricultural Development
Agricultural development is so important for a country
like ours. But this has been affecting the environment adversely.

30.  Biological interactions are the interactions between
organisms in a community.
 In the natural world no organism exists in absolute
isolation, and thus every organism must interact with the
environment and other organisms.
Inter relationship amongst living organisms
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31.  There are six possible combinations, ranging from
mutually beneficial through neutral to mutually harmful
interactions.
 The level of benefit or harm is continuous and not
separate, such that an interaction may be trivially
harmful through to deadly,
 for example. It is important to note that these interactions
are not always static. In many cases, two species will
interact differently under different conditions.

32. • There are six types of symbiotic relationships.
Parasitism +/-
Mutualism +/+
Commensalism +/0
Neutralism 0/0
Competition -/-
Predator/Prey +/-
• Each relationship can
be shown using + - or
0.
Effect on
X
Effect on
Y
Type of interaction
0 0 Neutralism
- 0 Amensalism
+ 0 Commensalism
- - Competition
+ + Mutualism
+ -
Predation or
Parasitism

33. Mutualism
• Mutualism—mutually beneficial
interaction between individuals of two
species (+/+).
• The contact between the two
organisms may be intimate or it may
be occasional or periodic.
• The best example for mutualism
relationships between animals, can be
of Egyptian plover and the crocodile.
In the tropical African jungles, the
crocodile lies keeping its mouth open.
• The plover flies in to the mouth of the
crocodile and eats the decaying meat
stuck in its teeth. The crocodile does
not eat the plover, but appreciates the
free dental care. This way, both of
them are benefited from each other.
Plover and Crocodile
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34. Commensalism:
Individuals of one species benefit,
while individuals of the other
species do not benefit and are not
harmed (+/0).
• example is of a birds nest in a tree.
The bird is benefitting because the
tree is giving the bird shelter and
the tree is not getting anything in
return.
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35.  Parasitism: Parasitism is the
situation where one organism
benefits while the other is harmed.
A + / - relationship.
 For example, mosquito is a
parasite, feeding on a human
while transferring the disease
called Malaria.
 Similarly, lice are an example
of parasitism because they feed
on blood from the humans head.
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36. • Neutralism: is the situation where both species remain
unaffected A 0 / 0 relationship.
• A Bactrian Camel and a Longtailed Tadpole Shrimp,
both living in the Gobi desert
•
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37. • Amensalism: is a relationship in
which a product of one organism
has a negative effect on another
organism.
• The bread mold penicillium is a
common example of this; penicillium
secrete penicillin, a chemical that
kills bacteria.
• This antibiotic compound inhibits the
growth of many species of bacteria
(in this picture, it's Staphylococcus
aureus) by interfering with the
normal formation of peptidoglycan in
the cell wall. 22

38. • A second example Allelopathy, in which some plants
produce chemical compounds that inhibit the growth of
nearby would-be competitors, is one type of amensalistic
interaction is the black walnut tree (Juglansnigra), which
secrete juglone, a chemical that harms or kills some
species of neighboring plants, from its roots.
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39. • Competition: can be defined as
an interaction between
organisms or species, in which
the fitness of one is lowered by
the presence of another.
• Limited supply of at least one
resource (such as food, water,
and territory) used by both is
required.
• Competition is one of many
interacting biotic and abiotic
factors that affect community
structure.
Male-male
interference
competition in
red deer.
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40. References/Sources
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images

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43. Book/Web Resources
• Environmental Studies by R. Rajagopalan