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ENVIRONMENTAL STUDIES
Effective from Academic Session 2015 and onwards
UNIVERSITY OF KASHMIR
COURSE MATERIAL
According to the Syllabus-2016
2ND Year (Semester IIIrd )
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PRELIMINARY
Keeping in view the prevailing conditions in the valley and the huge loss to the academics of the
students there-from, the Higher Education Department of J&K along-with the University of
Kashmir has initiated the process of uploading instructional/study material in a bid to provide
partial respite to the distressed undergraduate students of the valley. This move has been initiated
with the view to compensate the academic loss by engaging the students through e-learning
process.
The study/course material of environmental studies Effective from Academic Session 2015 and onwards
and According to the Syllabus-2016 2ND Year (Semester IIIrd) for the academic session-2016 conforms to
the guidelines set in the meeting held at A.S. College Srinagar Kashmir on 06-10-2016. Emphasis has
been laid on the view that the entire syllabus gets covered, which lay a foundation for the learners to
enable them in learning the course.
As all the educational institutions including degree colleges across the Kashmir valley for the last
more than three months are closed, so emphasis has been laid on providing the students with elearning in full support to combat the loss created due to the unrest in the valley. In this back
drop,e-lectures have been prepared to engage the students in e-learning process. Although the
study material allows the learner to learn at his/her place but exploratory and hands-on activities,
discussions, opinions and experiments can’t be compensated by e-learning. This mode of
learning can’t be a substitute or alternative to class work.
Meanwhile the students are encouraged to seek further information from their teachers so that
active participation is fostered.
DATED: 25/10/2016 (Srinagar Kmr)
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Course Preparation Team
Unit-I:
Prof. Aijaz Qureshi (A/P)
Government Women’s College, M. A. Road Srinagar Kashmir
Unit-II:
Dr. Showkat Subhan (A/P)
Government Degree College Women’s Sopore Kashmir
Unit-III:
Dr. Pervez Ahmad (A/P)
Government Degree College Tangdhar Kashmir
Unit-IV:
Dr. Abdul Qayoom (A/P)
Government Degree College Pulwama Kashmir
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Syllabus for BA/B.Sc./B.Com./B.Sc.IT/BBA/BCA/B.Tech./B.Pharma/BBA-MBA/OC &
MIL 2nd Year (Semester-III)
Subject: Environmental Studies
Effective from Academic Session 2015 and onwards
Unit 1: Understanding Environment
1.1 Environment: Concept and importance.
1.2 Components of Environment: Physical, Biological and Social.
1.3 Concept of ecological balance in nature.
1.4 Environment and human health.
1.5 Environmental overexploitation and sustainable development.
Unit 2: Ecosystems
2.1 Concept of an Ecosystem.
2.2 Structure of an ecosystem.
2.3 Concept of food chain, food webs and ecological pyramids.
2.4 Energy flow in an ecosystem.
2.5 Characteristic features of a terrestrial ecosystem and an aquatic ecosystem.
Unit 3: Natural Resources
3.1 Land resources: Global land use patterns, concept of waste land reclamation and
Desertification.
3.2 Forest resources: Use and consequences of over-exploitation.
3.3Water resources: Use and consequences of over-utilization, concept of water harvesting and
watershed management.
3.4 Food resources: World food problems and concept of sustainable agriculture.
3.5 Energy resources: Renewable and non renewable energy sources.
Unit 4: Biodiversity and its Conservation
4.1. Biodiversity: meaning levels and values (commercial, ecological, social and aesthetic).
4.2 Threats to the biodiversity: Habitat loss, poaching of wildlife, man-wildlife Conflicts.
4.3 Concept of endemic and exotic species.
4.4 Conservation of biodiversity: In-situ and Ex-situ.
4.5 Hot spots of biodiversity.
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UNIT I: UNDERSTANDING ENVIRONMENT
1.1.
ENVIRONMENT:
CONCEPT AND IMPORTANCE
Definition: Environment is the complete range of external conditions under which an organism
lives including physical, chemical and biological components of the environment.
Concept of Environment:
 It gives us the understanding of the interrelationships between plants, animals, microbes
(biotic) and air, water, soil, temperature (abiotic) components.
 It gives us the understanding of the multidisciplinary nature of the environment.
 It involves the studies of air, water, soil, plants, animals, microbes all are the basic
components (biotic and abiotic) which legitimize the humans to know about their
environment.
 The concept also introduces us to various issues associated with our surroundings.
 The concept of environment and its studies provides us the understanding of water, air
and soil pollution, climate, quality of life, global warming, earthquakes, geology,
geography etc.
 The concept also gives us an experience of monitoring our surroundings and making
assessment of the impacts of changes in environmental conditions.
 The concept also gives us the ability to provide managerial practices.
 Along with Physics, Chemistry, Geology, Atmospheric Science, Geography branches,
Mathematics, Statistics, Computer Sciences also help in modeling and management of
environment.
 Other subjects like Economics, Sociology and Education do help in understanding the
socio-economic aspects of environment.
Importance of Environment
The environmental study is helpful in solving many problems and also helps in understating the
fundamental relationship of the natural community. The study of environmental sciences is
important as it aims for the following:
1)
In solving environmental problems like:
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a. Pollution.
b. Depletion of Ozone layer.
c. Depletion of biodiversity.
d. Global warming.
e. Reducing energy resources.
f. Impact of mining and hydro electric projects.
g. Solid waste management.
h. Energy crisis.
2) Environmental studies are helpful in:
a. Sustaining life support system.
b. Hygenic living conditions and clean drinking water.
c. Town planning.
d. Location of industries.
1.2 COMPONENTS OF ENVIRONMENT
a) Physical or abiotic
Air
Water
Abiotic
Land
b) Biological or biotic
Plants
Animals
Biotic
Microbes
c) Social
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This includes the social conditions such as historical, economical, moral, cultural and politics
that affect the nature of an individual or community.
1.3 CONCEPT OF ECOLOGICAL BALANCE IN NATURE
 The term ecosystem was first coined by British ecologist A.G.Tansley in 1935 and
the term ecosystem was defined by him as “the system resulting from the integration
of all the living and non living factors of the environment”.
 The word Ecology comprises of two components- organism and environment. The
components are complex, dynamic and interdependent and are mutually reactive and
interrelated.
 The functioning of any system involves a series of cycles e.g. hydrological cycle and
the cycles of various nutrients and are driven by energy flow (solar energy).
 The continuation of life demands constant exchange and return of nutrients to and
from the different components of ecosystem.
 Therefore, the concept of ecosystem is and should be broad one and its maintenance
should emphasis obligatory relationships, interdependence, and casual relationships
i.e. coupling of components from functional point of view.
 According to Palmisana (1977) the recent system of ecosystem characterization may
be defined as a description of various processes and components comprising an
ecosystem and an understanding of their functional relationships.
 The above definition describes the important ecosystem components and functional
processes, besides providing a mechanism undertaken through integration of
components and functions.
 So, such an approach helps in:
a) Integration of complex ecological information.
b) Identification of gaps and lack in information.
c) Assessment of environmental impact and comprehensive explaining.
 Thus, the ecosystem characterization is one of the important tools needed to manage
and protect living resources.
 One of the universal character of all the ecosystems, whether aquatic or terrestrial is
the integration of autotrophic and heterotrophic components.
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1.4 ENVIRONMENT AND HUMAN HEALTH
Human health is directly related to environment. The physical characteristics of the globe have
determined his diet and hence his health. The relationship between human health and his
environment are interrelated. There are many ways in which the environment effects human
health. Some of them are as follows:
 Direct discharge of pollutants by industries into the air and water.
 In urban areas, current disease pattern is closely linked to the deterioration in the quality
of air and water.
 Human health is also influenced by quality of environment in the place of work.
 It has been recognized that the workers in certain occupations such as textile mills or
stone quarries suffer from occupational diseases.
 Deterioration of the environment such as existence of stagnant pools in villages and
cities.
 Many diseases carrying vectors have developed immunity to pesticides. As a result
malaria has reached endemic proportions to many parts of the country.
 Similarly diseases like Kala-azar are difficult to eradicate as the organisms spreading it
find increasing number of breeding places.
 Overcrowding, unhygienic conditions in cities, particularly in slums, have also
contributed to the spread of other communicable diseases such as tuberculosis and
cholera.
There are a number of many other factors manifested by the human activities which are
responsible for cause of health problems like:

Noise pollution

Radiations.

Indoor air pollution like
Tobacco smoke.
Fuels used for cooking and heating.
Poorly ventilated rooms or rooms are covered to retain heat in the winter
months.
Levels of economic conditions of every house hold
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 Health interventions become almost meaningless so long as much conditions prevail.
It has become more clear that “improving environmental conditions should form an
important part of healthcare because curative care alone will not suffice as more succumb to
these diseases”.
1.5:
ENVIRONMENTAL
OVEREXPLOITATION
AND
SUSTAINABLE
DEVELOPMENT
ENVIRONMENTAL OVEREXPLOITATION:
Nature has given us abundant resources in the form of water, air, vegetation, soil, wild animals,
metals, fossil fuels etc. These are the free gift to the mankind. Men are using all these resources
in some way or the other right from the dawn of civilization. Thus, utilization of resources, has
improved the development of any country or a region. In the course of the operation of natural
resources, man has ill-used its availability, thus affecting the natural ecosystem. Instead of
improving his living conditions, he has created major long-term problems and has been
catastrophic for the natural environment.
a) Overexploitation of Forest Resources
 The total forest area of the world in 1900 was about 7000 million hectares which
reduced to 2,890 Mha by 1975.
 According to one estimate, all tropical forests of the world would probably
disappear in the next 50 to 70 years, if the present rate of deforestation continues
unabated.
 Although, national policy laid down in 1952 considered 33% of forest cover of
only about 22.7% and the loss of our forest wealth continues at the rate of about
1.3 Mha per year.
 Deforestation is a consequence of over-exploitation of forest resources for space,
energy and materials.
 Expansion of agriculture is one of the prime causes of deforestation. As demands
on agricultural products rise, more and more land is brought under cultivation at
the cost of forests.
 Shifting cultivation also results in destruction of forests or deforestation.
 The deforestation leads to chain of consequences notably
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1. Change in climatic conditions
2. Degradation and erosion of soil
3. Economic loses and
4. Loss of biological diversity.
b) Overexploitation of Water Resources
 The ill effects of withdrawal of more water than the total annual input may be
drastic.
 . Over exploitation of ground water has resulted in receding of water table by several
metres in many parts of the world.
 The rapid rise in demand for fresh water is naturally the result of rapid growth in the
number of consumers and non -judicious use of this limited resource.
 Most of our surface water resources have become polluted and unfit for human use
because of large quantities of domestic sewage and industrial effluents disposed into
these water bodies.
 Deforestation besides over exploitation has been an important factor for the
depletion of underground water resources.
 Unless there is balance between water drawn from the water table and the inputs the
underground water table recedes deeper and deeper.
c) Land degradation
 Land degradation is damage to land that makes it less economically useful and less
biologically diverse.

This term is used specifically to refer to damages caused by human activities
rather than natural ones and human activities can indirectly contribute to environmental
changes that may accelerate the speed of land degradation.

People think of land degradation as a new thing, but it has been happening ever
since people started farming the land.

Or at least since they started using irrigation which can cause all kinds of trouble
even if it seems like it would be fairly harmless.

Farmland is prone to land degradation factors in India and covers about 600
million hectares.
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
The main factors responsible for soil degradation are:
a)
Soil erosion.
b)
Salinization
c)
Soil contamination.
d) Air Pollution
Air being very vital component of earth‘s environment which forms the basic of the diversity of
life on this planet, slight change in its composition can have varied effects on the survival of the
life.
 The presence of certain substances in air beyond those concentration levels that can
lead adverse effects on biotic as well as abiotic environmental factors is termed as air
pollution.
 Agricultural activities including the use of various pesticides pollute the air while
spraying of weedicides, insecticides and fungicides etc. The fumes are released into the
air and cause pollution.

There are varied and diverse effects of various pollutants in air on the biotic as well
as abiotic environment.

All the components of air, beyond the optimum levels cause damage to plants,
animals, human beings and the abiotic environment.
 Some of the major, integrated effects on air pollution in general are as follows
1.Increased higher concentration of green house gases in air (e.g. CO2, CH4, NO2, SO2,
CFC‘s, water vapour etc) have caused increase in average global temperature (Global
warming) which can lead to serious consequences.
2.Depletion of ozone layer by CFC‘s is yet another serious effect of air pollution. It was led
to increased inflow of ultraviolet radiations reaching the earth‘s surface which can lead
serious health hazards in humans and animals. Constant exposure can damage the
vegetation as well.
3.Acid rain is another consequence of air pollution. Gases like oxides of carbon; Sulphur,
nitrogen etc combine with water and fall down as acid rain which causes damage to
flora, fauna and abiotic structural assets like historical monuments etc. The effects are
more pronounced in aquatic systems.
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4.Carbon monoxide proves to be fetal even in small concentrations as it blocks hemoglobin
for binding of oxygen and reduces the oxygen carrying capacity of blood.
5.Increased ozone concentration in air can lead to pulmonary edema. It along with
aldehydes irritates eyes and respiratory organs. Air pollution leads to many respiratory
diseases including bronchitis and asthma due to the presence of particulate and
irritating gasses.
6.Lead and other metallic particulates have adverse effects on various physiological and
biochemical processes of organisms. Fluorides cause glurosis in animals.
7.Crops are adversely affected by increased concentrations of oxides of sulphur, nitrogen,
ozone etc
SUSTAINABLE DEVELOPMENT
Sustainability means the ability to last and resist depletion. G.H. Brundtland (1987), defined
sustainable development as “meeting needs of the present generation without compromising the
ability of future generations to meet their own needs”. United Nations Environment Programme
(UNEP) and World Wildlife Fund (WWF) laid down nine principles for sustainable
development:
1. Minimize depletion of non-renewable resources.
2. Conservation of earth’s vitality and diversity.
3. Change of personal attitudes and practices.
4. Improve the quality of life-supporting systems of the earth.
5. Keep the population within the carrying capacity of the earth.
6. Enable communities to care their own environment.
7. Respect and care for other communities.
8. Create a global alliance.
9. Provide framework for development and conservation.
 Two aspects of sustainable development:

Inter generational equality.

Intra generational equality.
 Steps for sustainable development:

Three R approach should be followed which states:
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
Reduce.

Reuse.

Recycle.
***********************************************************
UNIT 2: ECOSYSTEMS
2.1 Concept of an ecosystem.
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The term ecosystem was proposed by the British ecologist A.G.Tansley in 1935, but the concept
of the unity of organisms and environment can be traced back to very early biological literature.
In 1877 Karl Mobius used term ‘biocoenosis’ and in 1887 S.A.Forbes used the term ‘microcosm’
for different types of ecosystems.The concept of ecosystem is a very broad one and emphasizes
the obligatory relationships, the casual relationship and the interdependence of biotic and abiotic
components.
E.P.Odum a renowed ecologist stated that the ecosystem is the basic functional unit of organisms
and their environment, interacting with each other and within their own components.
An ‘ecosystem’ is a region with a specific and recognizable landscape form, such as a forest,
grassland, desert, wetland or coastal area. Thus the definition of any ecosystem can be said as the
living environment such as soil, air and water- constitute the ecosystem.
2.2: Structure and function of an ecosystem.
2.2.1: Producers, consumers and decomposers.
An ecosystem has two components-the biotic components, consisting of living things, and the
abiotic portion, consisting of elements that are not alive. The non-living constituents are said to
include the following categories: habitat, gases, solar radiation, temperature and moisture,
inorganic and organic nutrients. The living organisms include plants, animals and decomposers
according to their specific role in keeping the ecosystem operating as a stable interacting whole.
The function of an ecosystem reveals us how the energy flow takes place in the system by
studying food chains, food webs, ecological pyramids and interaction of producers, consumers
and decomposers.
Every biotic components (living organisms) need food for growth and development. Thus every
living organism is in some way dependent on other organisms. From a structural view point three
biotic components have been recognized:
(a) Producers: The producers are the autotrophic organisms, chiefly green plants, that utilize
radiant energy to manufacture food from simple inorganic substances like water, Co2, salts etc.
Plants take energy from the non-living environment and make it available to all living organisms
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and for themselves. They convert the light energy of the sun into chemical energy in the form of
organic compounds.
(b) Consumers: Consumers are heterotrophic organisms (primarily animals) and are either
directly or indirectly dependent upon autotrophs for food. The herbivores remain dependent upon
the green plants for their food and are the primary consumers. However, the primary consumers
also vary with the kind of the ecosystem. Elton(1939) gave the name “key industry animals” to
the herbivores because life of other prominent animals of a community depends upon these
herbivores. The herbivores are used as food for primary carnivores or secondary consumers.
(c) Decomposers: Like consumers, the decomposers are the heterotrophic organisms. They feed
on dead protoplasm, breaking down its complex organic components of cells from dead
producers and consumer organisms either into small organic molecules, which they utilize
themselves as saprophytes or into inorganic substances that can be used as raw materials by
green plants. Thus, the continous functioning of an ecosystem hinges on the activity of
decomposers in recycling of organic matter and are mostly bacteria and fungi.
2.2.2: Food chains, food webs and ecological pyramids.
Organic nutrients (energy) are transferred from producers to consumers and decomposers as
organisms eat and in turn are eaten by other organisms. This succession is called a food chain.
The food chain is divided into trophic levels comprised of all the organisms that obtain their food
by an identical number of steps.
Sun/CO2
Green
/H2O
Plants/vegetables
Sheep/Goat/Human
Wolf/Human
Tiger
The producers (autotrophs) comprise the first trophic level. The herbivores comprise the second
trophic level and the carnivores that consume the herbivores constitute the third trophic level.
The carnivores which consume third level carnivores comprise the fourth trophic level and so on.
All food chains begin at the producer level and all end at the decomposer levels.
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During transfer of energy from one trophic level to another some energy is always dispersed into
unavailable heat energy and is never 100% efficient. The shorter the food chain or nearer is the
organism to the beginning of the food chain, the greater is the available food energy.
In most ecosystems, many different food chains are possible and these overlap and are
interwined with one another to form what is called a community food web. Food web is simply a
diagram of all the trophic relationships among and between its component species. A food web is
generally composed of many food chains, each of which represents a single pathway up to the
food web. Thus, the population within the food web is linked by the various food chains through
which organic nutrients are transferred. The alternate pathways in a food web help to maintain
stability of the living community.
The greater the number of alternate pathways a food web has, the more stable is the community
of the living things which make up the web.
2.2.3: Ecological Pyramids
An ecological pyramid is a sort of geographical representation showing relationships between
the various trophic levels of a community. Ecological pyramids are of three general types.
(a). pyramid of numbers
(b). pyramid of biomass
(c). pyramid of energy
(a). pyramid of numbers: This type of pyramid shows the number of individual organisms at
each trophic level. In most of the ecosystems this type of pyramid shows upright structure
meaning the number of individuals goes on decreasing from base to apex. In a forest ecosystem
however, the pyramid of number is somewhat different in shape. The producers which are
mainly large sized trees are lesser in number and form the base of the pyramid. The herbivores,
which are the fruit eating birds, elephants, deer etc are more in number than the producers. Then
there is a gradual decrease in the number of successive carnivores, thus making the pyramid
again upright. However in a parasitic food chain the pyramids are always inverted.
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(b). pyramid of biomass: They are comparatively more fundamental, as they instead of
geometric factor, show the quantitative relationships of the standing crops. The pyramid of
biomass in grassland and forest are upright as there occurs a gradual decrease in biomass of
organisms at successive levels from the producers to the top carnivores. However in a pond, the
producers are small organisms their biomass is least and this value gradually shows an increase3
towards the apex of the pyramid, thus making the pyramid inverted in shape.
(c). pyramid of energy: Of the three types of ecological pyramids, the energy pyramid gives the
best picture of overall nature of the ecosystem. This type of pyramid represents the total amount
of energy utilized by different trophic level organisms of an ecosystem in unit area over a set
period of time. The pyramid of energy depicts the amount of energy flow to each successive
trophic level receives less total energy than the level below. So greater amount of energy is
available at the producer level and go decreasing in successive trophic levels, thus giving it
upright shape always.
2.3: Energy flow in an ecosystem
The ultimate source of energy in any type of ecosystem is the solar energy and this energy flows
from one organism to another in an ecosystem in a unidirectional manner.
Flow of energy in an ecosystem takes place through the food chain and it is this energy flow
which keeps the ecosystem going. The most important feature of this energy flow is that it is
unidirectional. Unlike the nutrients (like carbon, nitrogen, phosphorus etc.) which move in
acyclic manner and are reused by the producers after flowing through the food chain. The flow
of energy in an ecosystem follows the two laws of thermodynamics:
1st Law of Thermodynamics states that energy can neither be created nor be destroyed but it can
be transformed from one form to another. The solar energy captured by the green plants
(producers) gets converted into biochemical energy of plants and later into that of consumers.
2nd Law of Thermodynamics states that energy dissipates as it is used or in other words, it gets
converted from a more concentrated to dispersed form. As energy flows through the food chain,
there occurs dissipation of energy at every trophic level. The loss of energy takes place through
respiration, loss of energy in locomotion, running, hunting and other activities. At every level
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there is about 90% loss of energy and the energy transferred from one trophic level to the other is
only about 10%.
The diagrammatic representation of energy flow in an ecosystem reveals how energy goes on
decreasing when passing from one tropic level to another.
2.4:Characteristic features of a/an;
2.4.1: Terrestrial Ecosystem.
2.4.2:Aquatic Ecosystem.
The characters and extent of community succession in a given area depends on climate and soil
conditions. The climax community is achieved only if environmental factors permit a full
sequence of seral stages. All ecosystems resemble each other in the sense that all have same
components, i,e autotrophic and heterotrophic, interacting upon each other thus bringing about
circulation of materials. In one ecosystem, the climate and soil conditions are relatively uniform
and they favour the growth of a certain kind of climax community.
2.4.1: terrestrial Ecosystem:
The seas are characterized by constancy, the lands by variability. The seas have always existed
and been connected where as land masses have been considerably shifted, both vertically and
horizontally. Terrestrial habitats are naturally quite different from the aquatic habitats. Most
aquatic organisms die relatively soon after being exposed to air. Water diffuses and evaporates
so quickly from their bodies that cellular metabolism is disrupted and then destroyed. The
conservation of water is therefore, a major problem for land organisms. Terrestrial animals and
plants have special devices to conserve water. On land great variation in available water, ranging
from marshes at one extreme to waterless deserts at the other, determine the habitability of
particular land masses.
Important characteristic features of a terrestrial ecosystem which control and determine the
nature of all terrestrial ecosystems are abioticand biotic factors mentioned as below:
Abiotic components:
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The ecosystems of the terrestrial environment are most variable. Factors having significant effect
on life are given as:
Soil:
The major life supporting element of the terrestrial environment is soil, composed of mineral
matter interspersed with varying qualities of organic substances, air and water. The fertility and
structure of soil in various regions determines the amount and type of vegetation. This in turn
determines the numbers and varieties of consumers within the ecosystem.
Water:
The body of all organisms is composed of about 60-70% of water, that is why water is a major
limiting factor in terrestrial life. Usually terrestrial organisms living in moist habitats freely
consume and excrete large amounts of water. In arid regions, all organisms are physiologically
adopted for conservation of water.
Temperature:
Temperature vary greatly on land, not only from place to place but also with the season. The
surface temperature in some deserts may fall for below 0oC in winter and rise above 50oC in the
summer. No organism in its active state, can withstand the entire range of environmental
differences encountered on land. Each species has evolved adaptations for life in a specific
ecosystem.
Oxygen and Carbon dioxide:
Oxygen and Carbon dioxide are the only required substances in all terrestrial ecosystems that are
nearly constant in amounts. In air, oxygen is about 21% and carbon dioxide 0.032% by volume.
Both gases are vital requirements for two important processes i,e. photosynthesis and respiration.
Light:
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Light is the most important factor for producers or autotrophs for their photosynthetic activities.
Consumers depend upon producers. Thus the requirement of light to living beings can be
understood. Light intensity, quality and quantity on the earth’s surface varies greatly which is
due to angle of incidence, degree of latitude, climate and various biological factors.
Geographical barriers:
Land has also got geographical barriers which check free movement and result in the
development of ecosystem, free from outside biotic forces.
Biotic components:
Biotic components include producers, consumers and decomposers as stated as under;
(a). Producers: The producers are the autotrophic organisms, chiefly green plants, that utilize
radiant energy to manufacture food from simple inorganic substances like water, Co2, salts etc.
Plants take energy from the non-living environment and make it available to all living organisms
and for themselves. They convert the light energy of the sun into chemical energy in the form of
organic compounds.
(b). Consumers: Consumers are heterotrophic organisms (primarily animals) and are either
directly or indirectly dependent upon autotrophs for food. The herbivores remain dependent upon
the green plants for their food and are the primary consumers. However, the primary consumers
also vary with the kind of the ecosystem. Elton (1939) gave the name “key industry animals” to
the herbivores because life of other prominent animals of a community depends upon these
herbivores. The herbivores are used as food for primary carnivores or secondary consumers.
(c).Decomposers: Like consumers, the decomposers are the heterotrophic organisms. They feed
on dead protoplasm, breaking down its complex organic components of cells from dead
producers and consumer organisms
either into small organic molecules, which they utilize
themselves as saprophytes or into inorganic substances that can be used as raw materials by
green plants. Thus, the continuous functioning of an ecosystem hinges on the activity of
decomposers in recycling of organic matter and are mostly bacteria and fungi.
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On the basis of different biotic communities observed on different regions of terrestrial
ecosystems varying due to different abiotic conditions, there are different types of terrestrial
ecosystems mentioned below as:
*Coniferous forest ecosystem.
*Temperate deciduous forest ecosystem.
*Tropical rain forest ecosystem.
*Arctic ecosystem.
*Tundra ecosystem.
*Desert ecosystem.
4.2: Aquatic Ecosystem:
As 70% of the earth is covered by water, so aquatic ecosystem contribute much more as
compared to terrestrial ecosystem. Out of this 70% of water, 97% is marine water and 3% as
fresh water, which is (later) usable for human consumption and other agricultural activities etc.
The fresh water is available in the form of lakes, rivers, streams, ponds and wetlands and marine
water in seas and oceans.
There are two categories of freshwater ecosystems:
(a).Lentic water (standing) including ponds, lakes, wetlands.
(b).Lotic water (running) including streams, springs and rivers. Fresh water ecosystems have low
percentage of dissolved salts. They have fluctuating physical and chemical factors affecting flora
and fauna.
These different types of aquatic ecosystems have different characteristic features as both abiotic
and biotic components vary from one system to another and even in same ecosystem they vary
from one season to another season. Here some major aquatic ecosystems are briefly discussed:
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Of fresh water ecosystems, the lentic water (standing) habitats are generally divided into three
zones:
Example of Lake Ecosystem
(a). Littoral zone: This zone consists of bottom and shallow water areas where sunlight
penetrates. It is near the shore and contains the greatest number of different species. In littoral
zone producers are of two main types:
1. Rooted or benthic plants: e.g. water lilies, typha, ceratophyllum etc.
2. Phytoplankton or floating green plants e.g. algae and diatoms.
In this zone also the scene of the greatest concentration of animals distributed in
recognizable communities are.
*Freely swimming (nekton) e.g. beetles and bugs.
*Floating members (neuston) e.g. Protozoa and water striders.
*Vertebrates e.g. Frogs, salamanders, snakes etc.
*Decomposers are usually least clear.
(b). Limnetic or open water zone: As this zone is located in open water above the profundal
zone, so most of its inhabitants are microscopic. The production is limited to phytoplankton
including blue green and diatoms. One characteristic feature of limnetic zone producers is great
yearly fluctuations in population density. Consumers of this zone are mainly zooplankton
microscopic animals and fish.
(c). Profundal or deep zone: Light does not penetrate in profundal zone and the inhabitants
have to depend on the other zones for food, hence no producers in this zone. Decomposers
(Bacteria and fungi) predominate in this zone. Consumers of profundal zone are blood worms,
annelids and other small animals capable of surviving in a region of little light and low oxygen.
The scientific study of lakes is known as liminology. On the basis of the amount of nutrition they
provide for fishes and other inhabitants, lakes are categorized into:
Eutrophic, Mesotrophic and Oligotrophic lakes.
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*Eutrophic being shallow and rich in nutrients.
*Mesotrophic which are moderate in nutrient concentration.
*Oligotrophic being deep and relatively poor in nutrients.
Lotic waters:
Lotic waters are those which occur in fast running streams, springs, rivers etc. The biotic
communities in lotic waters are different from lentic waters due to differences in physical and
chemical conditions of their environments. Water currents, close association with surrounding
land areas, high oxygen concentration and ecological communities are adapted to such
conditions. In fast flowing water, the plants are usually submerged and are mainly made up of
algae and masses. The sandy bottom is occupied by burrowing aquatic animals such as worm
clams and insect larvae.
The abiotic components in both lentic and lotic water ecosystems comprise water, oxygen,
nitrogen, phosphorus, calcium, amino acids and humic acid etc. Producers take them in a small
amount in soluble form. Most of them remain inside the bodies of animals.
The Ocean Ecosystem
The oceans, which cover 70% of the earth’s surface, constitute one of the great reservoirs of
living things and of the essential nutrients needed by both land marine organisms. The average
depths of the oceans is roughly 4000 metres and life in oceans also depends upon light. The
oceans are divided into several general regions depending on the light penetration and depth of
the bottom.
Neritic zone:
Most continents are surrounded by a continental shelf, a more or less flat plain under about 200
metres of water but in some places much less. The shelf itself and waters over the shelf
constitute the neritic zone. The part of neritic zone near shore up to 50mts. having enough light
penetration, favouringplant growth is termed littoral. The neritic zone can be further sub-divided
into supratidal, intertidal and subtidal regions.
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Oceanic zone:
Beyond the neritic zone is the oceanic zone. The bottom slopes rapidly from the continental shelf
down to depth of 3000mts. and lower. The regions of these great depths are the abyssal regions.
No light ever penetrates this far. The temperature is virtually at abut 3oc. This part is called “blue
water”.
Euphotic zone:
The upper part of the ocean, into which enough light can penetrate to be effective in
photosynthesis, is known as the euphotic zone. The average lower limit of this is at about
100mts.
Abiotic components: In the marine environment, the most significant abiotic components
affecting the marine life are light, temperature, pressure, salinity, currents and tides.
Biotic components: Like other ecosystems the marine environment also has producers,
consumers and decomposers but the composition of these living organisms is different because
of different abiotic conditions and marine environment itself.
***********************************************************
UNIT 3: NATURAL RESOURCES
Topic:
Land Resource, global land use pattern
Objectives: To let the student know about
1. Availability of land resource
2. Importance of land resource
3. Pattern of land use
Land Resource:
Land is precious resource that forms the base for the emergence and development of all living
organisms including human beings. Out of total earth’s surface area about 29% is land and rest is
water. It measures about 13939 million hectares. Out of this available land resource throughout
the world, about 36.6% of the land area is covered by houses, factories, roads, railways deserts,
glaciers, mountains and polar ice marshes. About 30% of land is covered by forests and about
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22% by meadows and pastures. Only about 11.4% of total land area is fit for tilling and crop
cultivation.
Importance of land resource: As stated above land forms the base for the emergence and
development of all living organisms. It is one of the most important components of life support
system. We use land for various purposes like agriculture, settlements, forestry and other
purposes including nature reserves for conservation. Therefore, we depend upon land resource for
our food, fibre, fuel and other basic amenities of life.
Definition/explanation of land use: Land use may be defined as the arrangements, activities and
inputs people undertake in a certain land cover type to produce, change or maintain it. Land use
denotes how human use the biophysical or the ecological properties of land.
Global land use pattern: Land use pattern include the modification and management of land for
agriculture, settlements, forestry and other uses including nature reserves for conservation. Since
all land is not equal, each section or region of the world has its own soil characteristics, climate,
degree of slope and geographical location. When these are all taken into consideration, a proper
land use can be determined for each portion of the planet earth. Therefore, the global pattern of
land use varies from place to place and country to country. At the same time wise planning of the
land is necessary to keep the land and its soil able to provide food and other necessities of life.We
know that only about 29% of earth’s surface is land and rest about 71% is covered with water.
Major portion of the land i.e. about 52% is under forest cover, pastures and meadows throughout
the world. Around 37% covered by houses, factories, roads, railways deserts, glaciers, mountains
and polar ice marshes. Rest is available for tilling and crop cultivation.
Land use pattern in India: India has a total land area of 2.4% of the world’s total. Of this about
43% of land surface is covered by plains, 28% by plateaus and less than 30% comprises
mountains and hills. Nearly 44% of land surface is used for agriculture, 11-14% is covered with
forests, 4% pastures and grazing lands and 8% is used for housing, establishment of industries,
roads and dams etc.
What we learnt
1. Land as a resource: A precious resource that forms the base for emergence and development
of life. About 29% of the Earth’s surface is land and rest is covered with water.
2. Land use: The arrangements, activities and inputs people undertake in a certain land cover type
to produce, change or maintain it.
3. Land use pattern: The modification and management of land for agriculture, settlements,
forestry and other uses including nature reserves for conservation.
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Topic: Land Degradation and wasteland reclamation
Objectives: To let the student know about
1. What is land degradation
2. Causes of land degradation
3. Concept of degraded/wasteland reclamation
Land degradation
Land degradation refers to loss of fertility or productive capacity of the soil. With increasing
population growth the demand for fertile land for cultivation food, fibre and fuel wood has
increased considerably. With the result there is over-exploitation of land resources resulting in
land degradation.
Causes of land degradation
Various physical and chemical factors are responsible for degradation of land resources. Physical
factors like water and wind cause soil erosion. Although soil erosion is a natural process, it is
aggravated due to felling of trees and overgrazing. Other physical factors like wrong methods of
cultivation, urbanisation, industrialization, construction of dams etc. contribute in degradation of
land. Among chemical factors salinization, acidification, and accumulation of toxic chemicals
cause land degradation.
Concept of Wasteland Reclamation
What are wastelands?
Wastelands are those lands which are for one reason or the other; do not fulfil their life
sustaining potential. Increasing misuse of land resources has resulted into wastelands.
Degradation of land occurs due to erosion, desertification, mining, water-logging, salinity and
toxic effects of agrochemicals and industrial effluents. Water logging and salinisation are the
major causes which convert fertile land into wasteland.
How to reclaim wastelands?
There are a number of ways and means by which wasteland can be reclaimed for
productive purposes. Among them watershed management, wasteland afforestation and social
forestry programmes are noteworthy. Control of soil erosion and enhancement of soil fertility are
also important measures for improvement of land condition.
Deforestation for timber and fuel wood extraction and subsequent conversion of forest land
to agricultural or urban areas poses major threat for land degradation and also quicken the
process of wasteland formation. These factors are needed to be addressed properly in wasteland
reclamation process.
Examples of wastelands and their reclamation
1. Water logging
Water logging is caused due to over-irrigation of agricultural fields by farmers for good growth
of crops. Over-irrigation coupled with inadequate drainage results in excess accumulation of
underground water. It gradually forms a continuous column with the water table and the porespaces in soil get filled with water. This results in depletion of soil-air and roots of plants do not
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get adequate air for respiration. Crop yield falls as the soil strength declines and plants get
lodged.
Reclamation of water logged soils
Reclamation of water logged soils can be achieved by preventing over-irrigation and subsurface
drainage technology. Specific tree plantation is bio-drainage method to reclaim water logged
soils.
2. Salinisation
Salinasation of soils is one of the major causes of land degradation in the world. About one third
of the cultivable land area in the world is affected by salts. A major cause of salinisation is
excessive irrigation. Different kinds of salts get accumulated in the soil profile. pH of such soils
usually exceeds 8.0. Salinity causes stunted plant growth and lowers crop yield. Most of the
crops cannot tolerate high salinity.
Reclamation of saline soils
The most effective method to remove slats from saline soils is to flush them out by applying
good quality water. Another method is laying underground network of perforated drainage pipes
for flushing out slats slowly.
Sub-Topic: Desertification
Objectives: To let the student know about
1. What is desertification
2. Causes of desertification
3. Extent of desertification
4. Control of desertification
Desertification
Desertification is a process in which the productive potential of land in arid and semi-arid areas
of the world drops by 10% or more. Moderate desertification is 10-25% drop in productivity,
severe desertification causes 25-50% drop and very severe desertification results in more than
50% drop in productivity of land. Desertification is characterized by loss of vegetation cover,
depletion of ground water, salinisation and severe erosion.
Causes of Desertification: Formation of deserts may take place due to climate change, soil
erosion or may be due to abusive land use practices. Major causes responsible for desertification
include:
a. Deforestation: Loss of vegetation cover increases soil erosion, loss of fertility and loss of
water. Thus deforestation initiates desertification.
b. Overgrazing: The regions more seriously affected by desertification are the cattle
producing areas of the world. Increasing cattle population graze heavily in grasslands and
forests which in turn get dry and denuded. The dry denuded land becomes loose and more
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prone to erosion and thus plant growth is badly hampered leading to further
desertification.
c. Mining and quarrying: These activities are also responsible for loss of vegetal cover
and denudation of extensive land areas leading to desertification.
Extent of desertification
During the last 50 years about 900 million hectares of land have undergone desertification.
Amongst the most badly affected areas are the sub- Saharan Africa, the Middle East, Western
Asia, parts of Central and South America, Australia, and the western half of the United States.
Control of desertification
Some of the important measures to control desertification are:
1. Reforestation of denuded and overgrazed areas.
2. Reclamation of abandoned mines by landscaping and reforestation.
3. Better agricultural practices like terracing and contour farming to check soil erosion.
4. Crop rotation and multiple cropping should be adopted to maintain soil fertility
What we learnt
Land degradation: Land degradation is the loss of fertility or productive capacity of the soildue to various factors like soil erosion,
deforestation, overgrazing, water logging, salinisation,etc.
Wastelands:Wastelands are those lands which due to their misuse do not fulfil their lifesustaining potential.
Wasteland reclamation: It is a process by which wasteland can be reclaimed for productivepurposes.
Water logging: It is the formation of a continuous column of surface water with groundwater due to over-irrigation of crop fields.
Salinisation: It is the accumulation of various salts in soil profile which increases soil pHand inhibits plant growth. It is caused due to
over-irrigation of crop fields.
Desertification: It is a process in which the productive potential of land in arid and semi-aridareas of the world drops by 10% or more. It is
characterized by loss of vegetation cover,depletion of ground water, salinisation and severe erosion.
Topic: Forest resources
Objectives: To let the student know about
1. Availability of forest resources
2. Uses of forest resources
3. Over-exploitation of forest resources
4. Consequences of over-exploitation of forest resources
Forest Resources
Forests are renewable resource and are considered as ‘green gold’ of country due to their
immense socio-economic and environmental services. About 33% of the world’s land area is
covered with various types of forests. Former USSR accounts for about a 5th of world’s forests,
Brazil for about a 7th and Canada and USA each for 6-7%. However, almost everywhere the
cover of natural forests has declined. The greatest losses have occurred in tropical Asia where
one third of the forest resources have been destroyed.
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Uses of Forests
Forests are of immense value to human beings. Forests are very useful for industry and help in
rural economic growth. Forests have both commercial as well as environmental uses:
Commercial uses:
Forests provide a large number of commercial goods which include timber, firewood, pulpwood,
food items, spices, tannin, dyes, gum, resin, non-edible oils, rubber, fibres, lac, bamboo, canes,
fodder, medicines, drugs and many more items.
Ecological uses:
Ecological services provided by forests are:
 They produce oxygen which is vital for life on earth
 They reduce global warming by absorbing CO2 as raw material for photosynthesis
 Forests are homes of millions of plants and animals species
 Forests regulate water cycle
 Forests bind soil particles in their roots and prevent soil erosion
 Forests absorb many toxic gases and noise and thus help in preventing air and noise
pollution
Over Exploitation of Forests
Forests possess huge potential for human use and are exploited since early times. To meet
growing human demands forests are exploited in many ways including:
 Wood cutting for raw materials like timber, pulpwood, firewood etc.
 Deforestation for road construction
 Clearing of forests for expansion of agriculture fields to meet the food demands
 Clearing of forests for large scale mining
 Destruction of forests for construction of dams to generate hydro-electricity
 Degradation of forests due to over grazing
Consequences of over-exploitation of forests
Over-exploitation of forests has far reaching consequences like:
 It threatens the existence of many wildlife species due to destruction of their natural
habitats
 Water cycle gets disturbed which affects rainfall pattern
 Soil erosion and loss of soil fertility increases
 In hilly areas it often leads to landslides
 Due to loss of forests more CO2 is added to atmosphere and greenhouse effect is
enhanced
 There are increased chances of floods and droughts
 Scarcity of timber, firewood etc.
What we learnt
Forest Resources: Forests are renewable resource and are considered as ‘green gold’ of country due to
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their immense socio-economic and environmental services. About 33% of the world’s land area is
covered with various types of forests.
Over-exploitation of forest resources: It refers to destruction of forest resources to meet growing
human need and greed.
Topic: Water resources
Objectives: To let the student know about
1. Water resources and their types
2. Uses of water resources
3. Over-exploitation of water resources
4. Consequences of over-exploitation of water resources
Water Resources
Water is an essential natural resource on this earth on which all life depends. About 71% of the
earth’s surface is covered by water. Water is a very precious resource because out of total water
reserves of the world, about 97% is salty (marine) water and only 3% is fresh water. Even this
small fraction of water is not available to us as most of it is locked up in polar ice caps and less
than 1% is available to us in the form of ground water and surface water.
Types of water resources
There are two types of water resources – surface water and ground water.
1. Surface water: Surface water is further divided into fresh water and marine water. Fresh
water if found in the form of lakes, ponds, rivers, streams, and springs. Marine water
which accounts for about 97% of total water resources is salty and is not fit for direct
human consumption.
2. Ground water:Ground water constitutes about 9.86% of total fresh water resources.
Ground water is a major source for domestic consumption and agricultural uses.
Uses of water
Water is of multiple uses for all living organisms. Water is absolutely essential for all forms of
life. Human beings depend on water for almost every developmental activity. Major uses of
water include drinking, cooking, irrigation, transportation, washing, bathing , construction, waste
disposal and as coolant for thermal power plants.
Over-exploitation of water
With increasing human population and rapid development, the usage of water has increased
manifolds. Also various water sources have got polluted due to anthropogenic activities. Rivers
and streams have long been used for discharging and disposal wastes causing pollution in these
water bodies. Overuse of ground water has resulted in rapid depletion of groundwater in various
regions leading to lowering of water table and drying of wells. Pollution of groundwater has also
made it unfit for consumption in many areas.
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Consequences of over-exploitation of water resources
Discharge of wastes has resulted in pollution of surface water sources. Overuse of ground water
has also resulted in depletion of ground water in many regions. Consequently there has been
shortage of drinking water supply in many parts of the world. According to United Nations
estimates, more than 1 billion people do not even have access to safe drinking water and 2.4
billion do not have adequate sanitation facilities. It is estimated that by 2024, two-thirds of the
world population would by suffering from acute water shortage.
Sub-Topic: Rain-water harvesting
Objectives: To let the student know about
1. What is rain-water harvesting
2. Significance of rain-water harvesting
3. Techniques of rain-water harvesting
Rain-water Harvesting - definition
Rain water harvesting is a technique of increasing the recharge of ground water by capturing and
storing of rain water by constructing special water harvesting structures.
Significance of rainwater harvesting
Rainwater harvesting has great significance as it reduces surface run off loss and avoid flooding.
It meets increasing demands of water, supplement ground water and raises water table. It also
improves soil moisture and decreases soil erosion.
Methods/Techniques of Rain Water Harvesting
In ancient times rain water was collected in talabs, baawaris, hauz, etc. to be used in dry periods.
Traditionally rain water from roof tops is collected in water storage tanks from where it is
diverted to wells. Now-a-days rain water from large catchment areas is collected in check dams.
It is also collected by constructing ground water dams for storing water underground. In roof-top
rainwater harvesting, the rainwater from the top of the roofs is diverted to some surface tank or
pit which can be later used for several purposes. It can also be used to recharge underground
aquifers. Watershed management is another effective method of rain water harvesting.
Sub-Topic: Watershed management
Objectives: To let the student know about
1. What is watershed
2. Significance of watersheds
3. Watershed management - methods
Watershed
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The watershed is defined as the land area from which water drains under gravity to a common
drainage channel. The watershed can range from a few square kilometres to a few thousand
square kilometres in size.
Significance of watersheds
Watersheds affect us directly as they supply water for irrigation, hydro-power generation,
transportation, vegetation growth, reducing floods and droughts. However, the watersheds are
very often found to be degraded due to overgrazing, deforestation, mining, construction
activities, shifting cultivation, soil erosion, etc. so the management of watersheds becomes
extremely necessary.
Watershed management
Watershed management may be defined as the rational utilization of land and water resources of
optimum production causing minimum damage to the natural resources. Various methods of
watershed management include:
1. Water harvesting: it is done by proper storage of water with provision for use in dry
season.
2. Afforestation and agroforestry: it is promoted to prevent run off loss and soil erosion
and increase soil moisture. In high rainfall areas woody trees are grown in between crops
to substantially reduce the runoff and loss of fertile soil.
3. Mechanical measures: several mechanical measures like terracing, bench terracing, notill farming, contour cropping, strip cropping, check dams, retaining walls, etc. are
used/constructed to minimise runoff and soil erosion particularly on the slopes of the
watersheds.
4. Mining and quarrying: it should be done by scientific methods in watershed areas.
5. Public participation: people’s involvement including the farmers and tribals is the key
to success of any watershed management programmes. People’s involvement in
watershed management should be ensured through their proper education and awareness
and giving certain incentives.
What we learnt
Water Resources: Water is an essential natural resource on this earth on which all life depends. About
71% of the earth’s surface is covered by water of which about 97% is salty (marine) water and only 3%
is fresh water.
Over-exploitation of water resources: It refers to misuse and overuse of water resources by polluting
surface water and depletion of ground water.
Rain water harvesting: A technique of increasing the recharge of ground water by capturing and storing
of rain water.
Watershed management: It refers to rational utilization of land and water resources of optimum
production causing minimum damage to the natural resources.
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Topic: Food resources and world food problems
Objectives: To let the student know about
1. What are food resources
2. Staple food
3. World food problems
Food Resources
Food is an organic substance, which is necessary for growth and development of all living
organisms. There are thousands of edible plants and animals over the world however, the main
food resources include wheat, rice, maize, potato, barley, oats, pulses, millet cassava some
common fruits and vegetables, milk meat, fish and seafood.
Staple food
Among all food resources cereals like rice, wheat and maize are the major grains which
constitute half of all the agricultural crops. About 4 billion people in the developing countries
have wheat and rice as their staple food. Meat and milk are mainly consumed by more developed
nations. Fish and seafood constitute about 70 million metric tons of high quality protein to the
world’s diet.
World Food Problems
During the last 50 years world grain production has increase almost three times, but rapid
increase in population growth has outstripped food production. Due to huge population growth in
less developed countries, increased food has not benefited the common man. Every year 40
million people, 50% of which are young children between 1 to 5 years, die of undernourishment
and malnutrition. These figures emphasize the need to increase our food production, equitably
distribute it and also to control population growth. There are about 410 million undernourished
people on the earth. Some ill-effect of undernourishment and malnutrition include
 High child mortality
 Higher maternal mortality
 Impaired brain growth
 Poor school performance
India is the third largest producer of staple crops, but an estimated 300 million Indians are still
undernourished. It is because India constitutes 17% of world’s population but has only 2.4% of
world’s geographical area. Therefore, India’s food problems are directly related to population.
Sub-Topic: Sustainable Agriculture
Objectives: To let the student know about
1. What is agriculture
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2. Concept of sustainable agriculture
3. Steps to sustainable agriculture
Agriculture
Traditional agriculture is more near to natural conditions and usually results in low production. It
is still practiced in about half of the global population. But there are some impacts associated
with this type of agriculture like deforestation, soil erosion and depletion of nutrients. Modern
agriculture on the other hand, involves use of hybrid seeds, high-tech equipments, fertilizers,
pesticides and irrigation water. This has resulted into fertilizers related problems, pesticides
related problems, water logging, salinisation and land degradation. All these resulted to
unsustainability to present day agriculture.
Concept of sustainable agriculture
Sustainable agriculture is the successful management of resources for agricultureto satisfy the
changing human needs along with maintenance and enhancement of the quality of environment
and conservation of natural resources.
Steps for sustainable agriculture:
I. Efficient management of soil and water
Soil quality and fertility determine plant growth, so a number of measures should be taken
to check its quality and to improve it e.g.
a. Overgrazing should be avoided
b. Soil erosion removes nutrient rich top-soil as such various causes of soil erosion should
be minimised
c. Various causes of soil salinisation should be checked
d. Advantageous irrigation systems like drip irrigation, water sprinkling etc. should be
adopted
e. Multi-cropping should be adopted in which crop raising is combined with keeping of
livestock to get every type of food supply
f. Mixed cropping or multiple cropping should be adopted to restore soil fertility
g. Crop rotation which increases the soil fertility and crop production should be adopted
II. Use of organic manures, compost and fertilizers
a. Organic manures like farmyard manure, compost, green manure and vermicompost
should be used. These improve physical and nutritive status of the soil
b. Chemical fertilizers should be judiciously used to meet the mineral deficiency of the soil
III. Use of biofertilizers
These include symbiotic use of micro-organisms which increase the soil fertility
IV. Biological control of pests
Biological control involves the use of natural enemies of the pests to control their population
and thereby crop damage.
What we learnt
Food resources: Food resources refer to edible plants and animals which we consume for
growth. Main food resources include wheat, rice, maize, potato, barley, oats, pulses, millet
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cassava some common fruits and vegetables, milk meat, fish and seafood.
Food Problems: It refers to deficiency of staple food resulting in undernourishment and
malnutrition of people.
Sustainable agriculture: It refers to the successful, sustainable and ecofriendly management of
resources for agriculture.
Topic: Energy Resources and growing energy needs
Objectives: To let the student know about
1. Energy resources and their types
2. Growing energy needs
3. Watershed management - methods
2.6 Energy Resources
Energy is defined as the ability to do work. Per capita energy consumption of a nation is usually
considered as an index of its development. This is because almost all developmental activities
are directly or indirectly dependent upon energy.
A resource of energy is one that can provide adequate amount of energy in a usable form over a
long period of time. The resources of energy are of two types:
1. Renewable resources: which are being used by man, generated continuously by nature
and are inexhaustible e.g. solar energy, wind energy, tidal energy, hydropower, biomass
energy, bio-fuels, geothermal energy and hydrogen. They are also called as nonconventional sources of energy and can be used again and again in endless manner.
2. Non-renewable resources: they are not renewable for use and are not replenished by
nature if exhausted e.g. fossil fuels like coal, petroleum, natural gas and nuclear fuels like
uranium and thorium.
Growing energy needs
Prior to industrial revolution, the common source of energy were human/animal muscle power,
wind energy fire wood and vegetable oils. Now there is extensive use of fossil fuels as source of
energy as almost all developmental activities depend largely on energy. Agriculture, industry,
mining, transportation, lighting, cooling and heating all need energy. The fossil fuels like coal,
oil and natural gas are presently supplying 95% of world’s commercial energy. However, these
sources of energy are going to end in coming years. With the demands of growing population
and luxurious life styles, the world is facing further energy deficit. Countries like USA,
Switzerland, Norway, with high GNP (Gross National Product) show high energy use as
compared with countries like India and China.
In highly developed countries like USA per capita per day consumption of energy is around
2,50,000Kcals. In developing countries like India a man uses about 10,000 Kcals energy on an
average. A person in a rich country consumes almost as much energy in a single day as one
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person does in a whole year in a poor country. This clearly shows that our life style and standard
of living are closely related to energy needs.
Sub-Topic: Alternate sources of energy
Objectives: To let the student know about
1. The alternate sources of energy
2. Advantages and disadvantages of these resources
Alternate or Renewable Sources of Energy
The demand of energy supply due to population growth, development and changing life style has
increased manifold. Further the reduced availability of fossil fuels and the limited capacity of the
world to cope with the overwhelming pollution caused by fossil fuels are the reasons that have
forced the world to seek for alternate sources of energy.In near future, it is expected that fossil
fuel based energy will be replaced by sustainable energy system based on renewable clean and
non polluting energy resources, some of the alternate or non conventional sources of energy are:
1. Solar energy
2. Wind energy
3. Geothermal energy
4. Tidal energy
5. Biomass
Solar Energy
Sun is the ultimate source of energy and solar energy has the maximum potential of all the
sources of renewable energy. The Solar energy received by earth atmosphere is 1.5 1018
kwh/year. The solar energy received near earth’s space is approximately 1.4 kj/second/m 2 known
as solar constant.
Traditionally solar energy has been used for drying of clothes, cereals, eatables, and warmth.
Now solar energy is harnessed for various purposes like solar cooking, solar cells, solar water
heaters, solar power, solar furnace, etc.
Advantages of Using Solar Energy
1. Solar gadgets do not create pollution and hence are eco friendly
2. Maintenance cost is negligible
3. Cheap initial cost
4. Noiseless working.
5. The food cooked in solar cookers is more nutritious due to slow and inform heating.
Disadvantages / Limitations of solar energy
1. Solar gadgets fail to work in nights during cloudy day
2. Solar gadgets do not work in rainy days
3. Solar cooking takes more time, is cumbersome as the face of reflector has to change
according to the position of sun
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Wind Energy
Wind energy has tremendous potential to 25x 103 MW. Wind resources are mainly near the sea
coasts. The wind energy is harnessed by making use of wind mills. The minimum wind speed
required for satisfactory working of wind turbines is 15km/hr and in India, winds show relatively
low speed of 5-15 km/hr and hence exploitation of wind energy is an expensive project.The
largest wind farm of our country is near Kanyakumari in Tamil Nadu.
Advantages of Wind Energy
1. Abundant availability
2. It is non-polluting, hence eco friendly
3. Suitable for power generation in coastal and hilly areas
4. Can be used in remote places for power production
Disadvantages / Limitations
1. Highly unreliable and discontinuous as wind does not blow regularly and uniformly
2. Responsible for causing noise pollution
3. Due to its non uniformity the power generated is also not continuous
4. Mechanical energy of windmills has to be stored by batteries due to fluctuating nature of
winds.
Tidal Energy
Tides are formed by the gravitational effect of the sun and moon on earth. This gravitational
force causes rise and fall of water level of sea in sync with the rising and setting of moon. This
periodic rise and fall of seawater is called tide and can be used to produce electricity.
Tidal energy can be harnessed by constructing a tidal barrage. During high tide, sea water flows
into the reservoir of barrage and turns turbine, which in turn produces electricity by rotating
generators. During low tide, when sea level is low, the sea water stored into the reservoir flows
out into sea and turns the turbine.
In India, tidal power has great potential in areas like Gulf of Kuchh, Gulf of Cambay and Sunder
Bans.
Geothermal Energy
The energy available from natural, underground reservoirs of steam and hot water is called
geothermal power. There is an increase in temperature of the earth with increasing depth below
the surface. All the heat stored in the earth’s crust as thermal energy constitutes an inexhaustible
source of energy termed as geothermal energy.
Hot springs and volcanoes are the sources of geothermal energy. Hot water or underground
steam is used to operate turbines to generate electricity. Geothermal energy sources are being
exploited for sectors like space heating, poultry farming, chemical industries, mushroom
cultivation, etc.
Advantages of Geothermal Energy
1. It is an inexhaustible source of energy.
2. Naturally occurring so free of cost and no fuel required.
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3. Can be used to generate power for long periods of time thus show stability.
4. It causes negligible pollution.
Disadvantages / Limitations
1. Not absolutely pollution free, many gases like H, S, CO2, NH3 are produced.
2. Drilling operation is noisy.
3. Extensive land area is used.
Biomass
Biomass is the organic matter produced by plants or animals which may include wood, crop
residues, cattle dung, manure, agricultural waste, etc. It is basically indirect form of solar energy
which is converted to chemical energy by plants. Energy plantation of some fast growing trees
and non-woody grasses to produce energy either by burning directly or converted into fuels by
fermentation. Certain latex containing plants are also cultivated to produce gasoline. Such plants
are known as petro-crops. Biomass can also be fermented to alcohols like ethanol and methanol
which can be used as fuels.
What we learnt
Energy resources: The resources that can provide adequate amount of energy in a usable form over a
long period of time.
Renewable resources: Energy resources being used by man generated continuously by nature and are
inexhaustible.
Non-renewable resources: Energy resources that are not renewable after use and are not replenished
by nature if exhausted.
Growing energy needs: It refers to growing demands of energy by growing population to meet
luxurious life style requirements.
Alternate sources of energy: Sustainable energy system based on renewable clean and non polluting
energy resources.
UNIT 4: BIODIVERSITY AND ITS CONSERVATION
4.1 Introduction/meaning of biodiversity:
Biological diversity or Biodiversity in short is the sum of all the different species of
microorganisms, fungi, plants and animals living on earth and the variety of habitats in which
they live. They hold an immense value for man and are central to the survival of human
civilizations. The full range and extent of biodiversity is still not known, leave alone their
greatest values and benefits.
The term biodiversity has been defined differently. The Global convention on biodiversity
(CBD) has defined it as “the variability among living organisms from all sources including
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terrestrial, aquatic (fresh, estuarine and marine) and the ecological complexes of which
they are a part. This includes diversity within species, between species and of ecosystems.”
Levels of Biodiversity:
Generally three hierarchical levels of biodiversity are recognized namely genetic diversity,
species diversity and ecosystem diversity.
Genetic Diversity:
Genetic diversity occurs between the members of the same species. Within any given species
there can be several varieties, strains or races which slightly differ from each other in one or
more characteristics such as size, shape, resistance against diseases, pests, insects etc and
resilience to survival under adverse environmental conditions. Such variability in the genetic
makeup among individuals within a single species is referred to as genetic diversity.
Species with more number of races, varieties and strains are considered to be rich and more
diverse in its genetic organization. Genetic diversity is needed by any species to maintain its
reproductive vitality, resistance to disease and the ability to adapt to changing conditions.
Species diversity:
Species diversity represents the variety of species in different habitats on earth or in other words
we can say that species diversity refers to the total number of species i.e. species richness of our
earth. Species diversity can be measured on the basis of number of species in a region.
Currently about 1.9 million species are known but this is thought to be a significant
underestimate of the total member of species. It is estimated that the total number of species
could be 5-30 million on our earth and one more estimate by UNEP (1993-94), the total number
of species that might exist on earth range between 9-52 million.
Ecosystem Diversity:
Ecosystem diversity and ecological diversity is the variety of biotic and abiotic components that
interact with one another and it represents the collective response of a community of species to
different environmental conditions.
An ecosystem develops its own characteristic community of living organisms based upon the
availability of abiotic resources and conditions of the environment, so that is because different
types of ecosystems represent they unique diversity each with a characteristic biotic community.
Values of Biodiversity
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Biodiversity not only maintains the equilibrium of ecosystems, it is also an inexhaustible source
of potential new drugs. Biodiversity helps to sustain a healthy food chain and promotes water,
soil and air quality. Each species plays its own role i.e. has its own importance. Biodiversity is
vital to our biosphere’s health, stability and its proper functioning.
The global concern for the need to preserve biological diversity stems from its enormous
significance and inestimable value to mankind. Our tendency to evaluate everything in terms of
direct economic benefits or costs has resulted in the severe undervaluing of biodiversity in the
past. Even now it is not possible to convert the potential benefits of biodiversity into monetary
values for assessment.
However we can classify the values of biodiversity into direct and indirect values as shown in the
below figure.
Direct Values
Also known as use values and commodity values and are assigned to the products harvested by
people. The direct values include food resources like grains, vegetables, fruits which are obtained
from plant resources and meat, fish, egg, milk and milk products from animal resources. These
also include other values like medicine, fuel, timber, fiber, wool, wax, resin, and rubber, silk and
decorative items.
The direct values are of two types
•
Consumptive use value
•
Productive use value.
Consumptive use value: These are the direct values where the biodiversity products can be
harvested and consumed directly. Example food, fuel and drugs. These goods are consumed
locally and do not figure in national and international market.
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(a) Food
•
Plants: The most fundamental value of biological resources particularly plants is
providing food. Basically three crops viz wheat, maize, and rice constitute more than
two third of the food requirement all over the world.
•
Animals:
•
Fish: Through the development of aquaculture techniques fish and fish products have
become the largest source of protein in the world.
(b) Fuel: Since ages forests have provided wood which is used as a fuel. Moreover fossil
fuels like coal, petroleum, natural gas are also products of biodiversity which are directly
consumed by humans. All through fossil fuels have productive use values.
(c) Drugs and medicines: The traditional medical practices like ayurveda utilize plants or
their extracts directly. In allopathy, the pharmaceutical industry is much more dependent
on nature products. Many drugs though having productive use values are derived from
plants like
(i) Quinine: - The famous anti-malarial drug is obtained from cinchona tree.
(ii) Penicillin: - A famous antibiotic derived from pencillium, a fungus
•
Digitalis and Digitoxin from foxgloves have saved millions of heart patients.
•
Recently vinblastin and vincristine- two anti cancer drugs have been obtained from Rosy
Periwinkle plant which has anti cancer alkaloids.
Productive use values: These are the direct use values where the product is commercially sold
in national and international markets. Many industries are dependent upon these values.
Examples textile, leather, silk, pump, paper and pulp industry etc. although there is an
international ban on trade of products from endangered species like tusks of elephants, wool
from sheep, fur of many animals etc. these are traded in market and fetch a booming business.
Indirect values:
Biodiversity provides indirect benefits to human beings which support the existence of biological
life and other benefits which are difficult to quantify. There include social and culture values,
ethical values, aesthetic values, option values and environment service values.
Social and cultural values:
Many plants and animals are considered holy and sacred
inIndia and are worshiped like tulsi, peepal, cow, snake etc. In Indian society great cultural value
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is given to forest and as such tiger, peacock and lotus are named as the national animal, bird and
flower respectively.
Ethical:
These values are related to conservation of biodiversity where ethical issue of "all
life forms must be preserved" is laid down. There is an existence value which is attached to each
species because biodiversity is valuable for the survival of human race. More over all species
have a moral right to exist independent of our need for them.
Aesthetic value:
There is a great aesthetic value which is attached to biodiversity. Natural
landscape at undisturbed places are a delight to watch and also provide opportunities for
recreational activities like bird watching, photography etc. It promotes ecotourism which further
generates revenue by designing of Zoological parks, Botanical gardens, National parks, Wildlife
sanctuaries etc.
Optional value:
biodiversity.
These values include the unexplored or unknown potentials of
Environment service value: The most important benefits of biodiversity is maintenance
of environmental services which include
•
Carbon dioxide fixation through photosynthesis.
•
Maintaining of essential nutrients by carbon, Oxygen, Nitrogen, Sulphur, and
Phosphorous Cycles.
•
Maintaining water cycle and recharging of ground water.
•
Soil formation and protection from erosion.
•
Regulating climate by recycling moisture into atmosphere.
•
Detoxification and decomposition of waste.
4.2 Threats to Biodiversity
Biodiversity loss is one of the important and serious environmental threats that humanity faces.
In earths 5.5 billion year history there have been five major “mass extinctions” recorded in the
fossil record, the most recent of which, 65 million years ago, killed the last of the true dinosaurs.
Scholars believe that we are currently experiencing extinction rates rivaling or exceeding the
rates of the prehistoric mass extinctions.
Biodiversity losses can be attributed to the resource demands of our rapidly growing human
population. In modern times the human population has increased from 1 billion in 1900 to over 7
billion today. Like other living beings, we use natural resources to survive but we are far more
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resourceful and destructive to other life forms than any other species previously known. As the
world’s human population increases all the organisms on earth (including ourselves) must share
the same limited resources (food, water, space). Yet there is less and less natural habitat
remaining as land is developed for human habitation and activities.
Here are some of the major reasons which caused loss of biodiversity and are threats to
biodiversity.
1. Habitat loss and fragmentation: is considered by conservation biologists to be the primary
cause of biodiversity loss. Clearance of native vegetation for agriculture, housing, timber and
industry as well as draining wetlands and flooding valleys to form reservoirs, destroys these
habitats and all the organisms in them. In addition, this destruction can cause remaining habitats
fragmented and so too small for some organisms to persist or fragments may be too far apart for
other organisms to move between. Sometimes habitat fragmentation occurs due to construction
of roads, towers and canals. Habitat fragmentation divides populations into isolated groups that
not only limit the potential of species for dispersal and colonization but also reduces the foraging
ability of animals. These isolated, small, scattered populations are increasingly vulnerable to
inbreeding depression, high infant mortality and susceptible to environmental hardships and
consequently in the end, possible extinction.
2. Invasive alien species: They are the second greatest threat to biodiversity worldwide,
whether introduced for any purpose or accidently. Non- native species can cause severe problems
in the ecosystems they invade, from affecting individuals to causing huge changes in ecosystem
functioning and the extinction of many species. Virtually all ecosystems worldwide have
suffered invasion by the main taxonomic groups. This problem possibly gets worsened by
climate change and an increase in global trade and tourism. As well as the risks to human health
alien species inflict massive economic costs to agriculture, forestry, fisheries and other human
activities.
For example introduction of Nile Perch from North in Lake Victoria, Africa’s largest lake
has driven almost half of the 400 original fish species of the lake to near extinction.
3. Pollution: Pollution is currently poisoning all forms of life, both on land and in water and
contributing to climate change. Any chemical in the wrong place or in the wrong concentration
can be considered a pollutant. Transport, industry, construction, extraction, power generation and
agro forestry all contribute pollutants to the air, land and water. These chemicals can directly
affect biodiversity or lead to chemical imbalances in the environment that ultimately kill
individuals, species and habitats.
4. Climate change: Climate change brought about by emissions of greenhouse gases when
fossil fuels are burnt is making life uncomfortably hot for some species and uncomfortably cold
for others. This can lead to change in the abundance and distribution of individual species around
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the globe and will affect the crops we grow, cause a rise in sea levels and problems to many
coastal ecosystems. In addition the climate is becoming more unpredictable and extreme
devastating events are becoming more frequent.
5. Over exploitation and poaching: Over exploitation by humans causes massive destruction to
natural ecosystems. Exploitation of biodiversity occurs for good (e.g. fish), construction (e.g.
trees), industrial products (e.g. animals, blubber, skins), the pet trade (e.g. reptiles, fish, orchids,
fashion e.g. (fur, ivory) and traditional medicines (e.g. rhino horn). Selective removal of an
individual species can unbalance ecosystems and all other organisms within them. In addition the
physical removal of one species often harms other (e.g. fishing by catches). Poaching which
means illegal /unlawful trade of wild plants and animals through hunting, harvesting, fishing or
trapping is also causing loss of biodiversity at a very fast rate. The lure of spectacular profits
drives the illegal trade in endangered species and their products. In spite of laws prohibiting the
trade, consumers all over the world are willing to pay 95, 000 dollars for a Bengal tiger coat.
Similarly a coat made of South American Ocelet costs 40000 dollars. Poaching contributes to
loss of biodiversity. Poaching is of 3 types listed below:
i.Subsistence poaching: This refers to killing animals for survival.
ii.Commercial poaching: This refers to hunting animals in order to sell their products.
iii.Recreational or Sport or Game poaching: This refers to the hunting of wild animals for
recreational purposes or for fun.
Man- wildlife conflict
Man- wildlife conflict refers to the interaction between wild animals and people and the resultant
negative impact on people or their resources or wild animals or their habitat. It occurs when
growing human populations overlap with established wildlife territory creating reduction of
resources or life to some people and or wild animals.
As human population extends to wild animal habitats natural wildlife territory is displaced
the population density of wildlife and humans overlaps increasing their interactions thus
resulting in increased physical conflict. Byproducts of human existence offer unnatural
opportunity for wildlife in the form of food and shelter, resulting in increased interference and
potentially destructive threat for both man and animals.
Various forms of man wildlife conflict occur with various negative results some of these are
• Animals deaths
• Crop damage
• Damage to property
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• Destruction of habitat
• Injuries to people
• Livestock depredation
• Loss of human life such as by
Tiger Attacks: Tiger attacks are an extreme form of man wildlife conflict which occurs for
various resources and have claimed more human lives than attacks by any of the other big cats.
The most comprehensive study of deaths due to Tiger attacks estimates that at least 373,000
people died due to Tiger attacks between 1800 and 2009, the majority of these attacks occurring
in South and Southeast Asia. In Southeast Asia attacks gradually declined after peaking in the
nineteenth century, but attacks in South Asia have remained high particularly in the Sunder bans.
If a human comes too close to and surprises a sleeping or a feeding tiger (particularly if it is a
Tigress with cubs), Tiger may attack humans in a case of a “mistaken identity” (for example if a
human is crouching while collecting firewood or cutting grass) and sometimes when a tourist
gets too close.
These attacks actually happen due to shrinkage and loss of original habitat of wild animals. As
a result these wild animals find it difficult to thrive there because of shortage of food and other
necessary requirements and come out into direct conflict with human inhabitated areas. They
damage crops in agricultural fields and thereby resulting in economical loss to farmers. In
revenge farmers kill these wild animals and thereby causing loss of biodiversity.
Potential solutions to these conflicts include habitat conservation and preservation, electric
fencing, land use planning, community based natural resources management (CBNRM),
compensation, payment for environmental services, ecotourism, wildlife friendly products or
other field solutions.
In efforts reduce man wildlife conflict world wide fund for nature (WWF) has partnered with a
number of organizations to provide solutions around the globe. Their solutions are tailored to the
community and species involved. For example in Mozambique communities started to grow
more chili paper plants after making the discovery that elephants dislike and avoid plants
containing Capsaicin. This creative and effective method prevents elephants from trampling
community formers fields as well as protects the species.
4.3 Threatened Species
The term threatened species is used in the conservation context for species which are in one of
the below three categories: endangered, vulnerable and rare. Some species are marked as
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threatened where it is known that they are endangered, vulnerable or rare but there is not enough
information to say which of the three categories is appropriate.
The international union for conservation of nature and natural resources (IUCN) develops
different categories of species based on certain criteria.
•
The present and past distribution.
•
Decline in the number of population in Course of time.
•
Abundance and quality of natural habitat.
•
Biological and potential value of species.
The different categories are as under:
•
Endangered species: These are species which are in danger of extinction. The survival
of such species is difficult if the negative factors that have led to a decline in their
population continue to operate. The examples of such species are Black Buck, crocodile,
Indian wild Ass, Indian Rhino, Nepenthes khasiana, Kashmiri stag (Hangul) etc.
•
Vulnerable Species: These are species whose population has declined to levels from
where it is likely to move into the endangered category in the near future if the negative
factors continue to operate. The examples of such species are Blue sheep, Asiatic
elephant etc.
•
Rare species: Species with small world populations that are not at present endangered or
vulnerable but are at risk. These species are usually localized within restricted
geographical areas or habitats or are highly scattered over more extensive range e.g.
Farestia marcantha, whooping crane etc.
•
Extinct species: These are species which are not found after searches of known or likely
areas where they may occur. A species may be extinct from a local area, region, country,
continent or the entire earth. Examples of such species are the Asiatic cheetah, Pink head
duck, Dodo Bird.
Endemic species and Exotic species:
Species which is only found in a given region or location and nowhere else in the world is known
as an endemic species. An endemic species is one whose habitat is restricted to a particular area
or locality. The term could refer to an animal, a plant, a fungus or even a microorganism.
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India is quite rich in biodiversity endemism. About 33% of the country’s flora are endemic and
are concentrated mainly in the north east, Western Ghats, North West Himalaya and the
Andaman and Nicobar islands. Similarly 62% of the known amphibian species and 50% of the
lizards of the country are endemic with the majority occurring in the western- Ghats also a
hotspot of biodiversity.
Exotic Species
Exotic species are those organisms introduced into habitats where they are not native. Invasive
exotic species are organisms not native to a region and whose introduction causes economic or
environmental harm or harm to human health. In their natural habitats these organisms develop
stable populations and complex relationships with other species. When removed from the
predators, parasites, diseases and competitors that have kept their numbers in check, species
introduced into new habitats often over run their new home and crowd out native species once
established, exotic species can rarely be eliminated.
4.4 Conservation of Biodiversity:
Conservation may be defined as the management and sustainable use of the natural environment
and natural resources for ethical reasons and the benefits of humanity. (Fiedler and Jain 1992).
The IUCN defines conservation as the management of human use of the biosphere in order for it
to yield the greatest sustainable benefit to current generation while maintaining its potential to
meet the needs and aspirations of future
In –Situ conservation
In- situ conservation or on-site conservation means conservation of species in its natural habitat
i.e. in places where the species normally occurs. For the present discussions, following in-situ
conservation means have been taken into consideration.
National parks:
National park was first introduced in 1969 by IUCN as a means of a protected area. A national
park is an area dedicated to conserve the scenery (or environment) and natural objects and the
wildlife therein. In national parks private rights are non- existent and all forestry operations and
other usages such as grazing of domestic animals are prohibited. However the general public
may enter it for the purpose of observation and study, certain parts of the park are developed for
tourism in such a way that enjoyment will not disturb or scare the animals. Also a national park
is hitched to habitat for a particular wild animal species like Lion, Tiger, Rhinoceros, and Hangul
etc.
Wildlife Sanctuaries:
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A wildlife sanctuary, similar to national park, is dedicated to protect the wildlife but it considers
the conservation of species as Great Indian Bustard, pitcher plant etc and also the boundaries of
it is not limited by state legislation. Further in a sanctuary killing, hunting or capturing of any
species of birds and mammals is prohibited except and by or under the control highest authority
in the department responsible for management of the sanctuary. Private ownership may be
allowed to continue in a sanctuary and forestry and other usages are permitted to a extent that
they do not adversely affect wildlife.
Biosphere Reserves:
Biosphere reserves aim at conserving the biological diversity and genetic integrity of plants,
animals and microorganisms in their totality as part of the natural ecosystems, so as to ensure
their self perpetuation and unhindered evolution of the living resources. In Biosphere reserves
the whole area (ecosystem) is protected and not any one particular plant or animal species.
Furthermore Biosphere reserves are organized into three zones. At the centre of the reserve is a
core conservation zone, accorded the highest degree of protection from commercial resources
exploitation and other forms of destructive interference. In core zones only non- disruptive
research and monitoring are normally permitted.
A secondary shell around the core is designated as the buffer zone in which limited and regulated
human activities are permitted including ecologically oriented tourism, training, low impact
experimental research and traditional low intensity agriculture and resources gathering activities.
The territory landscape surrounding the buffer zone is the transition zone which as its name
implies serves as a boundary between the biosphere reserve and the surrounding landscape.
Human settlements and more intensive economic activities are permitted in the transition zone
again provided that they are fundamentally consistent with the protection of core.
Q: What is the difference between a sanctuary and a national park?
Hunting without permit is prohibited and grazing or movement of cattle is regulated in sanctuary.
But hunting and grazing are absolutely prohibited in national park which may be established
within or outside a sanctuary i.e. the difference is mostly the interference of human or human
activities in the area. In a sanctuary the human activities are allowed but in a national park the
human interference is totally prohibited.
Ex- Situ Conservation
Ex – situ conservation or off-site conservation means conservation of endangered plants and
animal species away from their natural habitat under human supervision/ care or in other words
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we can say that off-site conservation is conservation in captivity under human care. For the
present discussions, following ex-situ conservation means have been taken into consideration.
(i)
Seed gene bank: These are cold storages where seeds are kept under controlled
temperature and humidity for storage and this is easiest way to store the germ plasma of
plants at low temperature. Seeds preserved under controlled conditions (minus
temperature) remain viable for long durations of time.
(ii)
Gene bank: Genetic variability also is preserved by gene bank under normal
growing conditions. These are cold storages where germ plasm is kept under controlled
temperature and humidity for storage; this is an important way of preserving the genetic
resources.
(iii)
Tissue culture: Cryopreservation of disease free meristems is very helpful. Long
term culture of excised roots and shoots are maintained. Meristem culture is very popular in
plant propagation as it is virus and disease free method of multiplication.
(iv)
Botanical gardens: A botanical garden is a place where flowers, fruits and
vegetables are grown. The botanical gardens provide beauty and calm environment. Most
of them have started keeping exotic plants for educational and research purposes.
(v)
Zoological Gardens: In zoos wild animals are maintained in captivity and
conservation of wild animals (rare, endangered species).
In world there are about 800
zoos. Such zoos have about 3000 species of vertebrates.
4.5 Hotspots of Biodiversity:
The hotspot of biodiversity concept was first of all introduced by a British ecologist Norman
Myers in 1988, wherein he recognized that a modest number of ecosystems accounted for a high
percentage of biodiversity. Conservation international (CI) has identified these biologically rich
areas under the greatest threats of destruction as biodiversity hotspots. These hotspots are
identified on the basis of three criteria:



the number of species present,
number of those species found exclusively in an ecosystem and
The degree of threats they face.
Thus hotspots of biodiversity are such areas on the surface of earth which have high species
richness as well as high species endemism. Earlier Norman Myers and a team of scientists (2000)
had updated the list of such areas to 25. But currently there are 34 hotspots of biodiversity in the
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world. They represent just 2.3% of Earth’s land surface, but they support more than half of the
world’s plant species as endemics. These areas and the species present within them are both
under high levels of threat and of significant global value based on their uniqueness. Therefore,
operations that occur within global biodiversity hotspots should follow rigorous biodiversity
assessments to prevent further biodiversity loss within these areas. This is a global scale
approach based on coarse scale ecoregions that therefore, has limited use for site-scale
assessment and decision making. Biodiversity hotspots will include areas of high biodiversity
importance as well as degraded land and urban areas and therefore more detailed assessments are
needed to locate the actual distribution of biodiversity within these areas.
India's rich biological diversity - its immense range of ecosystems, species and genetic forms is
by virtue of its tropical location, climate and physical features. Almost 60-70% of the total
global Biodiversity could be found in just 17 out of the over 200 countries of the world. Such
large concentrations of biodiversity in small parts of the world give rise to the concept of mega
diversity which was first proposed at the Smithsonian biodiversity conference in 1988. So far
there have been identified 12 such countries which have been tagged as mega diversity countries
or megacentres of biodiversity. The mega diversity countries or centers are Mexico, Columbia,
Brazil, Peru, Ecuador, Zaire, Madagascar, Indonesia, Malaysia, India, China and Australia.
Thus India is one of the 12 mega diversity centers in the world. India just having 2.4% of the
total land area of the world, contributes almost 8.22% of the global known biodiversity.
India has three major hotspots. The rate of deforestation in these areas is very high and
ecosystems have reached at a fragile stage.
The Western Ghats: The Western Ghats are a chain of hills that run along the western edge of
peninsular India. They run parallel to the west coast of India and constitute more than 1600 km
strip of forests in the states of Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala. These
regions have moist deciduous forest and rain forest. The region shows high species diversity as
well as high levels of endemism. There are over 6000 vascular plants belonging to over 2500
genera in this hotspot, of which over 3000 are endemic. Nearly 77% of the amphibians and 62%
of the reptile species found here are found nowhere else. The region also harbors over 450 bird
species, about 140 mammalian species, 260 reptiles and 175 amphibians. Over 60% of the
reptiles and amphibians are completely endemic to the hotspot.
The Eastern Himalayas: The Eastern Himalayas is the region encompassing Bhutan, northeastern India, and southern, central, and eastern Nepal. There are 10,000 species of plants in the
Himalayas, of which one-third are endemic and found nowhere else in the world. Few
threatened endemic bird species such as the Himalayan Quail, Cheer pheasant. Western tragopan
is found here, along with some of Asia’s largest and most endangered birds such as the
Himalayan vulture and White-bellied heron. The Eastern Himalayan hotspot has nearly 163
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globally threatened species including the One-horned Rhinoceros, the Wild Asian Water buffalo
and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species.
Indo-Burma: The Indo-Burma hotspot comprises the Southeast Asian nations of Vietnam,
Thailand, Cambodia, Laos, Myanmar (formerly, Burma), and portions of eastern India and
southern China. It follows along the coast extending thousands of miles and includes the islands
within the South China Sea, Gulf of Thailand, Andaman Sea, and the Bay of Bengal. IndoBurma is made up of widely diverse ecosystems, including mixed wet and dry evergreen forests,
deciduous and mountain forests, lowland floodplains, swamps, and mangroves. Of the 13,500
vascular species found in Indo-Burma, 52 percent are endemic to the region, including a wide
array of orchids and tropical hardwoods. Among vertebrates, the numbers are similar: 54 percent
of amphibian, 39 percent of reptile, and 16 percent of mammal species are endemic to the area.
Twenty percent of the world’s freshwater turtle species and about 10 percent of the world's
freshwater fish species live in Indo-Burma.
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