NCERT Textbook: Biodiversity & Conservation - UPSC PDF Download

 Page 1


BIODIVERSITY AND CONSERVATION
Y
ou have already learnt about the
geomorphic processes particularly
weathering and depth of weathering
mantle in different climatic zones.  See the
Figure 6.2 in Chapter 6 in order to recapitulate.
You should know that this weathering mantle
is the basis for the diversity of vegetation and
hence, the biodiversity. The basic cause for
such weathering variations and resultant
biodiversity is the input of solar energy and
water. No wonder that the areas that are rich
in these inputs are the areas of wide spectrum
of biodiversity.
Biodiversity as we have today is the result
of 2.5-3.5 billion years of evolution. Before
the advent of humans, our earth
supported more biodiversity than in any
other period. Since, the emergence of
humans, however, biodiversity has begun
a rapid decline, with one species after
another bearing the brunt of extinction
due to overuse. The number of species
globally vary from 2 million to 100 million,
with 10 million being the best estimate.
New species are regularly discovered
most of which are yet to be classified (an
estimate states that about 40 per cent of
fresh water fishes from South America
are not classified yet). Tropical forests are
very rich in bio-diversity.
Biodiversity is a system in constant
evolution, from a view point of species, as well
as from view point of an individual organism.
The average half-life of a species is estimated
at between one and four million years, and 99
per cent of the species that have ever lived on
the earth are today extinct. Biodiversity is not
found evenly on the earth. It is consistently
richer in the tropics. As one approaches the
polar regions, one finds larger and larger
populations of fewer and fewer species.
Biodiversity itself is a combination of two
words, Bio (life) and diversity (variety). In
simple terms, biodiversity is the number and
variety of organisms found within a specified
geographic region. It refers to the varieties of
plants, animals and micro-organisms, the
genes they contain and the ecosystems they
form. It relates to the variability among living
organisms on the earth, including the
variability within and between the species and
that within and between the ecosystems.
Biodiversity is our living wealth. It is a result
of hundreds of millions of years of evolutionary
history.
Biodiversity can be discussed at three
levels : (i) Genetic diversity; (ii) Species diversity;
(iii) Ecosystem diversity.
Genetic Diversity
Genes are the basic building blocks of various
life forms. Genetic biodiversity refers to the
variation of genes within species. Groups of
individual organisms having certain
similarities in their physical characteristics are
called species. Human beings genetically
belong to the homo sapiens group and also
differ in their characteristics such as height,
colour, physical appearance, etc., considerably.
This is due to genetic diversity. This genetic
diversity is essential for a healthy breeding of
population of species.
CHAPTER
© NCERT
not to be republished
Page 2


BIODIVERSITY AND CONSERVATION
Y
ou have already learnt about the
geomorphic processes particularly
weathering and depth of weathering
mantle in different climatic zones.  See the
Figure 6.2 in Chapter 6 in order to recapitulate.
You should know that this weathering mantle
is the basis for the diversity of vegetation and
hence, the biodiversity. The basic cause for
such weathering variations and resultant
biodiversity is the input of solar energy and
water. No wonder that the areas that are rich
in these inputs are the areas of wide spectrum
of biodiversity.
Biodiversity as we have today is the result
of 2.5-3.5 billion years of evolution. Before
the advent of humans, our earth
supported more biodiversity than in any
other period. Since, the emergence of
humans, however, biodiversity has begun
a rapid decline, with one species after
another bearing the brunt of extinction
due to overuse. The number of species
globally vary from 2 million to 100 million,
with 10 million being the best estimate.
New species are regularly discovered
most of which are yet to be classified (an
estimate states that about 40 per cent of
fresh water fishes from South America
are not classified yet). Tropical forests are
very rich in bio-diversity.
Biodiversity is a system in constant
evolution, from a view point of species, as well
as from view point of an individual organism.
The average half-life of a species is estimated
at between one and four million years, and 99
per cent of the species that have ever lived on
the earth are today extinct. Biodiversity is not
found evenly on the earth. It is consistently
richer in the tropics. As one approaches the
polar regions, one finds larger and larger
populations of fewer and fewer species.
Biodiversity itself is a combination of two
words, Bio (life) and diversity (variety). In
simple terms, biodiversity is the number and
variety of organisms found within a specified
geographic region. It refers to the varieties of
plants, animals and micro-organisms, the
genes they contain and the ecosystems they
form. It relates to the variability among living
organisms on the earth, including the
variability within and between the species and
that within and between the ecosystems.
Biodiversity is our living wealth. It is a result
of hundreds of millions of years of evolutionary
history.
Biodiversity can be discussed at three
levels : (i) Genetic diversity; (ii) Species diversity;
(iii) Ecosystem diversity.
Genetic Diversity
Genes are the basic building blocks of various
life forms. Genetic biodiversity refers to the
variation of genes within species. Groups of
individual organisms having certain
similarities in their physical characteristics are
called species. Human beings genetically
belong to the homo sapiens group and also
differ in their characteristics such as height,
colour, physical appearance, etc., considerably.
This is due to genetic diversity. This genetic
diversity is essential for a healthy breeding of
population of species.
CHAPTER
© NCERT
not to be republished
FUNDAMENTALS OF PHYSICAL GEOGRAPHY 136
Species Diversity
This refers to the variety of species. It relates to
the number of species in a defined area. The
diversity of species can be measured through
its richness, abundance and types. Some areas
are more rich in species than others. Areas rich
in species diversity are called hotspots of
diversity (Figure 16.5).
Ecosystem Diversity
You have studied about the ecosystem in the
earlier chapter. The broad differences between
ecosystem types and the diversity of habitats
and ecological processes occurring within each
ecosystem type constitute the ecosystem
diversity. The ‘boundaries’ of communities
(associations of species) and ecosystems are not
very rigidly defined. Thus, the demarcation of
ecosystem boundaries is difficult and complex.
ecosystem evolves and sustains without any
reason.  That means, every organism, besides
extracting its needs, also contributes something
of useful to other organisms.  Can you think of
the way we, humans contribute to the
sustenance of ecosystems.  Species capture
and store energy, produce and decompose
organic materials, help to cycle water and
nutrients throughout the ecosystem, fix
atmospheric gases and help regulate the
climate. These functions are important for
ecosystem function and human survival. The
more diverse an ecosystem, better are the
chances for the species to survive through
adversities and attacks, and consequently, is
more productive.  Hence, the loss of species
would decrease the ability of the system to
maintain itself.  Just like a species with a high
genetic diversity, an ecosystem with high
biodiversity may have a greater chance of
adapting to environmental change. In other
words, the more the variety of species in an
ecosystem, the more stable the ecosystem is
likely to be.
Economic Role of Biodiversity
For all humans, biodiversity is an important
resource in their day-to-day life. One important
part of biodiversity is ‘crop diversity’, which is
also called agro-biodiversity. Biodiversity is
seen as a reservoir of resources to be drawn
upon for the manufacture of food,
pharmaceutical, and cosmetic products. This
concept of biological resources is responsible
for the deterioration of biodiversity. At the same
time, it is also the origin of new conflicts dealing
with rules of division and appropriation of
natural resources. Some of the important
economic commodities that biodiversity
supplies to humankind are: food
crops, livestock, forests, fish, medicinal
resources, etc.
Scientific Role of Biodiversity
Biodiversity is important because each species
can give us some clue as to how life evolved
and will continue to evolve. Biodiversity also
helps in understanding how life functions and
the role of each species in sustaining
Importance of Biodiversity
Biodiversity has contributed in many ways to
the development of human culture and, in
turn, human communities have played a major
role in shaping the diversity of nature at the
genetic, species and ecological levels.
Biodiversity plays the following roles:
ecological, economic  and scientific.
Ecological Role of Biodiversity
Species of many kinds perform some function
or the other in an ecosystem.  Nothing in an
Figure 16.1 : Grasslands and sholas in Indira Gandhi
National Park, Annamalai, Western Ghats — an
example of ecosystem diversity
© NCERT
not to be republished
Page 3


BIODIVERSITY AND CONSERVATION
Y
ou have already learnt about the
geomorphic processes particularly
weathering and depth of weathering
mantle in different climatic zones.  See the
Figure 6.2 in Chapter 6 in order to recapitulate.
You should know that this weathering mantle
is the basis for the diversity of vegetation and
hence, the biodiversity. The basic cause for
such weathering variations and resultant
biodiversity is the input of solar energy and
water. No wonder that the areas that are rich
in these inputs are the areas of wide spectrum
of biodiversity.
Biodiversity as we have today is the result
of 2.5-3.5 billion years of evolution. Before
the advent of humans, our earth
supported more biodiversity than in any
other period. Since, the emergence of
humans, however, biodiversity has begun
a rapid decline, with one species after
another bearing the brunt of extinction
due to overuse. The number of species
globally vary from 2 million to 100 million,
with 10 million being the best estimate.
New species are regularly discovered
most of which are yet to be classified (an
estimate states that about 40 per cent of
fresh water fishes from South America
are not classified yet). Tropical forests are
very rich in bio-diversity.
Biodiversity is a system in constant
evolution, from a view point of species, as well
as from view point of an individual organism.
The average half-life of a species is estimated
at between one and four million years, and 99
per cent of the species that have ever lived on
the earth are today extinct. Biodiversity is not
found evenly on the earth. It is consistently
richer in the tropics. As one approaches the
polar regions, one finds larger and larger
populations of fewer and fewer species.
Biodiversity itself is a combination of two
words, Bio (life) and diversity (variety). In
simple terms, biodiversity is the number and
variety of organisms found within a specified
geographic region. It refers to the varieties of
plants, animals and micro-organisms, the
genes they contain and the ecosystems they
form. It relates to the variability among living
organisms on the earth, including the
variability within and between the species and
that within and between the ecosystems.
Biodiversity is our living wealth. It is a result
of hundreds of millions of years of evolutionary
history.
Biodiversity can be discussed at three
levels : (i) Genetic diversity; (ii) Species diversity;
(iii) Ecosystem diversity.
Genetic Diversity
Genes are the basic building blocks of various
life forms. Genetic biodiversity refers to the
variation of genes within species. Groups of
individual organisms having certain
similarities in their physical characteristics are
called species. Human beings genetically
belong to the homo sapiens group and also
differ in their characteristics such as height,
colour, physical appearance, etc., considerably.
This is due to genetic diversity. This genetic
diversity is essential for a healthy breeding of
population of species.
CHAPTER
© NCERT
not to be republished
FUNDAMENTALS OF PHYSICAL GEOGRAPHY 136
Species Diversity
This refers to the variety of species. It relates to
the number of species in a defined area. The
diversity of species can be measured through
its richness, abundance and types. Some areas
are more rich in species than others. Areas rich
in species diversity are called hotspots of
diversity (Figure 16.5).
Ecosystem Diversity
You have studied about the ecosystem in the
earlier chapter. The broad differences between
ecosystem types and the diversity of habitats
and ecological processes occurring within each
ecosystem type constitute the ecosystem
diversity. The ‘boundaries’ of communities
(associations of species) and ecosystems are not
very rigidly defined. Thus, the demarcation of
ecosystem boundaries is difficult and complex.
ecosystem evolves and sustains without any
reason.  That means, every organism, besides
extracting its needs, also contributes something
of useful to other organisms.  Can you think of
the way we, humans contribute to the
sustenance of ecosystems.  Species capture
and store energy, produce and decompose
organic materials, help to cycle water and
nutrients throughout the ecosystem, fix
atmospheric gases and help regulate the
climate. These functions are important for
ecosystem function and human survival. The
more diverse an ecosystem, better are the
chances for the species to survive through
adversities and attacks, and consequently, is
more productive.  Hence, the loss of species
would decrease the ability of the system to
maintain itself.  Just like a species with a high
genetic diversity, an ecosystem with high
biodiversity may have a greater chance of
adapting to environmental change. In other
words, the more the variety of species in an
ecosystem, the more stable the ecosystem is
likely to be.
Economic Role of Biodiversity
For all humans, biodiversity is an important
resource in their day-to-day life. One important
part of biodiversity is ‘crop diversity’, which is
also called agro-biodiversity. Biodiversity is
seen as a reservoir of resources to be drawn
upon for the manufacture of food,
pharmaceutical, and cosmetic products. This
concept of biological resources is responsible
for the deterioration of biodiversity. At the same
time, it is also the origin of new conflicts dealing
with rules of division and appropriation of
natural resources. Some of the important
economic commodities that biodiversity
supplies to humankind are: food
crops, livestock, forests, fish, medicinal
resources, etc.
Scientific Role of Biodiversity
Biodiversity is important because each species
can give us some clue as to how life evolved
and will continue to evolve. Biodiversity also
helps in understanding how life functions and
the role of each species in sustaining
Importance of Biodiversity
Biodiversity has contributed in many ways to
the development of human culture and, in
turn, human communities have played a major
role in shaping the diversity of nature at the
genetic, species and ecological levels.
Biodiversity plays the following roles:
ecological, economic  and scientific.
Ecological Role of Biodiversity
Species of many kinds perform some function
or the other in an ecosystem.  Nothing in an
Figure 16.1 : Grasslands and sholas in Indira Gandhi
National Park, Annamalai, Western Ghats — an
example of ecosystem diversity
© NCERT
not to be republished
BIODIVERSITY AND CONSERVATION 137
ecosystems of which we are also a species.  This
fact must be drawn upon every one of us so
that we live and let other species also live their
lives.
It is our ethical responsibility to consider
that each and every species along with us have
an intrinsic right to exist.  Hence, it is morally
wrong to voluntarily cause the extinction of any
species. The level of biodiversity is a good
indicator of the state of our relationships with
other living species. In fact, the concept of
biodiversity is an integral part of many human
cultures.
LOSS OF BIODIVERSITY
Since the last few decades, growth in human
population has increased the rate of
consumption of natural resources. It has
accelerated the loss of species and habitation
in different parts of the world. Tropical regions
which occupy only about one-fourth of the
total area of the world, contain about three-
fourth of the world human population. Over-
exploitation of resources and deforestation
have become rampant to fulfil the needs of large
population. As these tropical rain forests
contain 50 per cent of the species on the earth,
destruction of natural habitats have proved
disastrous for the entire biosphere.
Natural calamities such as earthquakes,
floods, volcanic eruptions, forest fires,
droughts, etc. cause damage to the flora and
fauna of the earth, bringing change the
biodiversity of respective affected regions.
Pesticides and other pollutants such as
hydrocarbons and toxic heavy metals destroy
the weak and sensitive species. Species which
are not the natural inhabitants of the local
habitat but are introduced into the system, are
called exotic species. There are many
examples when a natural biotic community of
the ecosystem suffered extensive damage
because of the introduction of exotic species.
During the last few decades, some animals like
tigers, elephants, rhinoceros, crocodiles, minks
and birds were hunted mercilessly by poachers
for their horn, tusks, hides, etc. It has resulted
in the rendering of certain types of organisms
as endangered category.
The International Union of Conservation of
Nature and Natural Resources (IUCN) has
classified the threatened species of plants and
animals into three categories for the purpose
of their conservation.
Endangered Species
It includes those species which are in danger
of extinction. The IUCN publishes information
about endangered species world-wide as the
Red List of threatened species.
Vulnerable Species
This includes the species which are likely to
be in danger of extinction in near future if the
factors threatening to their extinction continue.
Survival of these species is not assured as their
population has reduced greatly.
Figure 16.3 : Zenkeria Sebastinei — a critically
endangered grass in Agasthiyamalai peak (India)
Figure 16.2 : Red Panda — an endangered species
© NCERT
not to be republished
Page 4


BIODIVERSITY AND CONSERVATION
Y
ou have already learnt about the
geomorphic processes particularly
weathering and depth of weathering
mantle in different climatic zones.  See the
Figure 6.2 in Chapter 6 in order to recapitulate.
You should know that this weathering mantle
is the basis for the diversity of vegetation and
hence, the biodiversity. The basic cause for
such weathering variations and resultant
biodiversity is the input of solar energy and
water. No wonder that the areas that are rich
in these inputs are the areas of wide spectrum
of biodiversity.
Biodiversity as we have today is the result
of 2.5-3.5 billion years of evolution. Before
the advent of humans, our earth
supported more biodiversity than in any
other period. Since, the emergence of
humans, however, biodiversity has begun
a rapid decline, with one species after
another bearing the brunt of extinction
due to overuse. The number of species
globally vary from 2 million to 100 million,
with 10 million being the best estimate.
New species are regularly discovered
most of which are yet to be classified (an
estimate states that about 40 per cent of
fresh water fishes from South America
are not classified yet). Tropical forests are
very rich in bio-diversity.
Biodiversity is a system in constant
evolution, from a view point of species, as well
as from view point of an individual organism.
The average half-life of a species is estimated
at between one and four million years, and 99
per cent of the species that have ever lived on
the earth are today extinct. Biodiversity is not
found evenly on the earth. It is consistently
richer in the tropics. As one approaches the
polar regions, one finds larger and larger
populations of fewer and fewer species.
Biodiversity itself is a combination of two
words, Bio (life) and diversity (variety). In
simple terms, biodiversity is the number and
variety of organisms found within a specified
geographic region. It refers to the varieties of
plants, animals and micro-organisms, the
genes they contain and the ecosystems they
form. It relates to the variability among living
organisms on the earth, including the
variability within and between the species and
that within and between the ecosystems.
Biodiversity is our living wealth. It is a result
of hundreds of millions of years of evolutionary
history.
Biodiversity can be discussed at three
levels : (i) Genetic diversity; (ii) Species diversity;
(iii) Ecosystem diversity.
Genetic Diversity
Genes are the basic building blocks of various
life forms. Genetic biodiversity refers to the
variation of genes within species. Groups of
individual organisms having certain
similarities in their physical characteristics are
called species. Human beings genetically
belong to the homo sapiens group and also
differ in their characteristics such as height,
colour, physical appearance, etc., considerably.
This is due to genetic diversity. This genetic
diversity is essential for a healthy breeding of
population of species.
CHAPTER
© NCERT
not to be republished
FUNDAMENTALS OF PHYSICAL GEOGRAPHY 136
Species Diversity
This refers to the variety of species. It relates to
the number of species in a defined area. The
diversity of species can be measured through
its richness, abundance and types. Some areas
are more rich in species than others. Areas rich
in species diversity are called hotspots of
diversity (Figure 16.5).
Ecosystem Diversity
You have studied about the ecosystem in the
earlier chapter. The broad differences between
ecosystem types and the diversity of habitats
and ecological processes occurring within each
ecosystem type constitute the ecosystem
diversity. The ‘boundaries’ of communities
(associations of species) and ecosystems are not
very rigidly defined. Thus, the demarcation of
ecosystem boundaries is difficult and complex.
ecosystem evolves and sustains without any
reason.  That means, every organism, besides
extracting its needs, also contributes something
of useful to other organisms.  Can you think of
the way we, humans contribute to the
sustenance of ecosystems.  Species capture
and store energy, produce and decompose
organic materials, help to cycle water and
nutrients throughout the ecosystem, fix
atmospheric gases and help regulate the
climate. These functions are important for
ecosystem function and human survival. The
more diverse an ecosystem, better are the
chances for the species to survive through
adversities and attacks, and consequently, is
more productive.  Hence, the loss of species
would decrease the ability of the system to
maintain itself.  Just like a species with a high
genetic diversity, an ecosystem with high
biodiversity may have a greater chance of
adapting to environmental change. In other
words, the more the variety of species in an
ecosystem, the more stable the ecosystem is
likely to be.
Economic Role of Biodiversity
For all humans, biodiversity is an important
resource in their day-to-day life. One important
part of biodiversity is ‘crop diversity’, which is
also called agro-biodiversity. Biodiversity is
seen as a reservoir of resources to be drawn
upon for the manufacture of food,
pharmaceutical, and cosmetic products. This
concept of biological resources is responsible
for the deterioration of biodiversity. At the same
time, it is also the origin of new conflicts dealing
with rules of division and appropriation of
natural resources. Some of the important
economic commodities that biodiversity
supplies to humankind are: food
crops, livestock, forests, fish, medicinal
resources, etc.
Scientific Role of Biodiversity
Biodiversity is important because each species
can give us some clue as to how life evolved
and will continue to evolve. Biodiversity also
helps in understanding how life functions and
the role of each species in sustaining
Importance of Biodiversity
Biodiversity has contributed in many ways to
the development of human culture and, in
turn, human communities have played a major
role in shaping the diversity of nature at the
genetic, species and ecological levels.
Biodiversity plays the following roles:
ecological, economic  and scientific.
Ecological Role of Biodiversity
Species of many kinds perform some function
or the other in an ecosystem.  Nothing in an
Figure 16.1 : Grasslands and sholas in Indira Gandhi
National Park, Annamalai, Western Ghats — an
example of ecosystem diversity
© NCERT
not to be republished
BIODIVERSITY AND CONSERVATION 137
ecosystems of which we are also a species.  This
fact must be drawn upon every one of us so
that we live and let other species also live their
lives.
It is our ethical responsibility to consider
that each and every species along with us have
an intrinsic right to exist.  Hence, it is morally
wrong to voluntarily cause the extinction of any
species. The level of biodiversity is a good
indicator of the state of our relationships with
other living species. In fact, the concept of
biodiversity is an integral part of many human
cultures.
LOSS OF BIODIVERSITY
Since the last few decades, growth in human
population has increased the rate of
consumption of natural resources. It has
accelerated the loss of species and habitation
in different parts of the world. Tropical regions
which occupy only about one-fourth of the
total area of the world, contain about three-
fourth of the world human population. Over-
exploitation of resources and deforestation
have become rampant to fulfil the needs of large
population. As these tropical rain forests
contain 50 per cent of the species on the earth,
destruction of natural habitats have proved
disastrous for the entire biosphere.
Natural calamities such as earthquakes,
floods, volcanic eruptions, forest fires,
droughts, etc. cause damage to the flora and
fauna of the earth, bringing change the
biodiversity of respective affected regions.
Pesticides and other pollutants such as
hydrocarbons and toxic heavy metals destroy
the weak and sensitive species. Species which
are not the natural inhabitants of the local
habitat but are introduced into the system, are
called exotic species. There are many
examples when a natural biotic community of
the ecosystem suffered extensive damage
because of the introduction of exotic species.
During the last few decades, some animals like
tigers, elephants, rhinoceros, crocodiles, minks
and birds were hunted mercilessly by poachers
for their horn, tusks, hides, etc. It has resulted
in the rendering of certain types of organisms
as endangered category.
The International Union of Conservation of
Nature and Natural Resources (IUCN) has
classified the threatened species of plants and
animals into three categories for the purpose
of their conservation.
Endangered Species
It includes those species which are in danger
of extinction. The IUCN publishes information
about endangered species world-wide as the
Red List of threatened species.
Vulnerable Species
This includes the species which are likely to
be in danger of extinction in near future if the
factors threatening to their extinction continue.
Survival of these species is not assured as their
population has reduced greatly.
Figure 16.3 : Zenkeria Sebastinei — a critically
endangered grass in Agasthiyamalai peak (India)
Figure 16.2 : Red Panda — an endangered species
© NCERT
not to be republished
FUNDAMENTALS OF PHYSICAL GEOGRAPHY 138
Rare Species
Population of these species is very small in the
world; they are confined to limited areas or
thinly scattered over a wider area.
conservation strategy has suggested the
following steps for biodiversity conservation:
(i) Efforts should be made to preserve the
species that are endangered.
(ii) Prevention of extinction requires proper
planning and management.
(iii) Varieties of food crops, forage plants,
timber trees, livestock, animals and
their wild relatives should be preserved;
(iv) Each country should identify habitats
of wild relatives and ensure their
protection.
(v) Habitats where species feed, breed, rest
and nurse their young should be
safeguarded and protected.
(vi) International trade in wild plants and
animals be regulated.
To protect, preserve and propagate the
variety of species within natural boundaries,
the Government of India passed the Wild Life
(Protection) Act, 1972, under which national
parks and sanctuaries were established and
biosphere reserves declared.  Details of these
biosphere reserves are given in the book India:
Physical Environment (NCERT, 2006).
There are some countries which are situated
in the tropical region; they possess a large
number of the world’s species diversity.  They
are called mega diversity centres.  There are
12 such countries, namely Mexico, Columbia,
Ecuador, Peru, Brazil, Democratic Republic of
Congo, Madagascar, China, India, Malaysia,
Indonesia and Australia in which these centres
are located. In order to concentrate resources
on those areas that are most vulnerable, the
International Union for the Conservation of
Nature and Natural Resources (IUCN) has
identified certain areas as biodiversity hotspots
(Figure 16.5).  Hotspots are defined according
to their vegetation.  Plants are important
because these determine the primary
productivity of an ecosystem.  Most, but not all,
of the hotspots rely on species-rich ecosystems
for food, firewood, cropland, and income from
timber.  In Madagascar, for example, about 85
per cent of the plants and animals are
found nowhere else in the world, Other
hotspots in wealthy countries are facing
CONSERVATION OF BIODIVERSITY
Biodiversity is important for human existence.
All forms of life are so closely interlinked that
disturbance in one gives rise to imbalance in
the others. If species of plants and animals
become endangered, they cause degradation
in the environment, which may threaten
human being’s own existence.
There is an urgent need to educate people
to adopt environment-friendly practices and
reorient their activities in such a way that our
development is harmonious with other life forms
and is sustainable. There is an increasing
consciousness of the fact that such conservation
with sustainable use is possible only with the
involvement and cooperation of local
communities and individuals. For this, the
development of institutional structures at local
levels is necessary. The critical problem is not
merely the conservation of species nor the
habitat but the continuation of process of
conservation.
The Government of India along with 155
other nations have signed the Convention of
Biodiversity at the Earth Summit held at
Rio de Janeiro, Brazil in June 1992. The world
Figure 16.4 : Humbodtia decurrens Bedd — highly rare
endemic tree of Southern Western Ghats (India)
© NCERT
not to be republished
Page 5


BIODIVERSITY AND CONSERVATION
Y
ou have already learnt about the
geomorphic processes particularly
weathering and depth of weathering
mantle in different climatic zones.  See the
Figure 6.2 in Chapter 6 in order to recapitulate.
You should know that this weathering mantle
is the basis for the diversity of vegetation and
hence, the biodiversity. The basic cause for
such weathering variations and resultant
biodiversity is the input of solar energy and
water. No wonder that the areas that are rich
in these inputs are the areas of wide spectrum
of biodiversity.
Biodiversity as we have today is the result
of 2.5-3.5 billion years of evolution. Before
the advent of humans, our earth
supported more biodiversity than in any
other period. Since, the emergence of
humans, however, biodiversity has begun
a rapid decline, with one species after
another bearing the brunt of extinction
due to overuse. The number of species
globally vary from 2 million to 100 million,
with 10 million being the best estimate.
New species are regularly discovered
most of which are yet to be classified (an
estimate states that about 40 per cent of
fresh water fishes from South America
are not classified yet). Tropical forests are
very rich in bio-diversity.
Biodiversity is a system in constant
evolution, from a view point of species, as well
as from view point of an individual organism.
The average half-life of a species is estimated
at between one and four million years, and 99
per cent of the species that have ever lived on
the earth are today extinct. Biodiversity is not
found evenly on the earth. It is consistently
richer in the tropics. As one approaches the
polar regions, one finds larger and larger
populations of fewer and fewer species.
Biodiversity itself is a combination of two
words, Bio (life) and diversity (variety). In
simple terms, biodiversity is the number and
variety of organisms found within a specified
geographic region. It refers to the varieties of
plants, animals and micro-organisms, the
genes they contain and the ecosystems they
form. It relates to the variability among living
organisms on the earth, including the
variability within and between the species and
that within and between the ecosystems.
Biodiversity is our living wealth. It is a result
of hundreds of millions of years of evolutionary
history.
Biodiversity can be discussed at three
levels : (i) Genetic diversity; (ii) Species diversity;
(iii) Ecosystem diversity.
Genetic Diversity
Genes are the basic building blocks of various
life forms. Genetic biodiversity refers to the
variation of genes within species. Groups of
individual organisms having certain
similarities in their physical characteristics are
called species. Human beings genetically
belong to the homo sapiens group and also
differ in their characteristics such as height,
colour, physical appearance, etc., considerably.
This is due to genetic diversity. This genetic
diversity is essential for a healthy breeding of
population of species.
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FUNDAMENTALS OF PHYSICAL GEOGRAPHY 136
Species Diversity
This refers to the variety of species. It relates to
the number of species in a defined area. The
diversity of species can be measured through
its richness, abundance and types. Some areas
are more rich in species than others. Areas rich
in species diversity are called hotspots of
diversity (Figure 16.5).
Ecosystem Diversity
You have studied about the ecosystem in the
earlier chapter. The broad differences between
ecosystem types and the diversity of habitats
and ecological processes occurring within each
ecosystem type constitute the ecosystem
diversity. The ‘boundaries’ of communities
(associations of species) and ecosystems are not
very rigidly defined. Thus, the demarcation of
ecosystem boundaries is difficult and complex.
ecosystem evolves and sustains without any
reason.  That means, every organism, besides
extracting its needs, also contributes something
of useful to other organisms.  Can you think of
the way we, humans contribute to the
sustenance of ecosystems.  Species capture
and store energy, produce and decompose
organic materials, help to cycle water and
nutrients throughout the ecosystem, fix
atmospheric gases and help regulate the
climate. These functions are important for
ecosystem function and human survival. The
more diverse an ecosystem, better are the
chances for the species to survive through
adversities and attacks, and consequently, is
more productive.  Hence, the loss of species
would decrease the ability of the system to
maintain itself.  Just like a species with a high
genetic diversity, an ecosystem with high
biodiversity may have a greater chance of
adapting to environmental change. In other
words, the more the variety of species in an
ecosystem, the more stable the ecosystem is
likely to be.
Economic Role of Biodiversity
For all humans, biodiversity is an important
resource in their day-to-day life. One important
part of biodiversity is ‘crop diversity’, which is
also called agro-biodiversity. Biodiversity is
seen as a reservoir of resources to be drawn
upon for the manufacture of food,
pharmaceutical, and cosmetic products. This
concept of biological resources is responsible
for the deterioration of biodiversity. At the same
time, it is also the origin of new conflicts dealing
with rules of division and appropriation of
natural resources. Some of the important
economic commodities that biodiversity
supplies to humankind are: food
crops, livestock, forests, fish, medicinal
resources, etc.
Scientific Role of Biodiversity
Biodiversity is important because each species
can give us some clue as to how life evolved
and will continue to evolve. Biodiversity also
helps in understanding how life functions and
the role of each species in sustaining
Importance of Biodiversity
Biodiversity has contributed in many ways to
the development of human culture and, in
turn, human communities have played a major
role in shaping the diversity of nature at the
genetic, species and ecological levels.
Biodiversity plays the following roles:
ecological, economic  and scientific.
Ecological Role of Biodiversity
Species of many kinds perform some function
or the other in an ecosystem.  Nothing in an
Figure 16.1 : Grasslands and sholas in Indira Gandhi
National Park, Annamalai, Western Ghats — an
example of ecosystem diversity
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BIODIVERSITY AND CONSERVATION 137
ecosystems of which we are also a species.  This
fact must be drawn upon every one of us so
that we live and let other species also live their
lives.
It is our ethical responsibility to consider
that each and every species along with us have
an intrinsic right to exist.  Hence, it is morally
wrong to voluntarily cause the extinction of any
species. The level of biodiversity is a good
indicator of the state of our relationships with
other living species. In fact, the concept of
biodiversity is an integral part of many human
cultures.
LOSS OF BIODIVERSITY
Since the last few decades, growth in human
population has increased the rate of
consumption of natural resources. It has
accelerated the loss of species and habitation
in different parts of the world. Tropical regions
which occupy only about one-fourth of the
total area of the world, contain about three-
fourth of the world human population. Over-
exploitation of resources and deforestation
have become rampant to fulfil the needs of large
population. As these tropical rain forests
contain 50 per cent of the species on the earth,
destruction of natural habitats have proved
disastrous for the entire biosphere.
Natural calamities such as earthquakes,
floods, volcanic eruptions, forest fires,
droughts, etc. cause damage to the flora and
fauna of the earth, bringing change the
biodiversity of respective affected regions.
Pesticides and other pollutants such as
hydrocarbons and toxic heavy metals destroy
the weak and sensitive species. Species which
are not the natural inhabitants of the local
habitat but are introduced into the system, are
called exotic species. There are many
examples when a natural biotic community of
the ecosystem suffered extensive damage
because of the introduction of exotic species.
During the last few decades, some animals like
tigers, elephants, rhinoceros, crocodiles, minks
and birds were hunted mercilessly by poachers
for their horn, tusks, hides, etc. It has resulted
in the rendering of certain types of organisms
as endangered category.
The International Union of Conservation of
Nature and Natural Resources (IUCN) has
classified the threatened species of plants and
animals into three categories for the purpose
of their conservation.
Endangered Species
It includes those species which are in danger
of extinction. The IUCN publishes information
about endangered species world-wide as the
Red List of threatened species.
Vulnerable Species
This includes the species which are likely to
be in danger of extinction in near future if the
factors threatening to their extinction continue.
Survival of these species is not assured as their
population has reduced greatly.
Figure 16.3 : Zenkeria Sebastinei — a critically
endangered grass in Agasthiyamalai peak (India)
Figure 16.2 : Red Panda — an endangered species
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FUNDAMENTALS OF PHYSICAL GEOGRAPHY 138
Rare Species
Population of these species is very small in the
world; they are confined to limited areas or
thinly scattered over a wider area.
conservation strategy has suggested the
following steps for biodiversity conservation:
(i) Efforts should be made to preserve the
species that are endangered.
(ii) Prevention of extinction requires proper
planning and management.
(iii) Varieties of food crops, forage plants,
timber trees, livestock, animals and
their wild relatives should be preserved;
(iv) Each country should identify habitats
of wild relatives and ensure their
protection.
(v) Habitats where species feed, breed, rest
and nurse their young should be
safeguarded and protected.
(vi) International trade in wild plants and
animals be regulated.
To protect, preserve and propagate the
variety of species within natural boundaries,
the Government of India passed the Wild Life
(Protection) Act, 1972, under which national
parks and sanctuaries were established and
biosphere reserves declared.  Details of these
biosphere reserves are given in the book India:
Physical Environment (NCERT, 2006).
There are some countries which are situated
in the tropical region; they possess a large
number of the world’s species diversity.  They
are called mega diversity centres.  There are
12 such countries, namely Mexico, Columbia,
Ecuador, Peru, Brazil, Democratic Republic of
Congo, Madagascar, China, India, Malaysia,
Indonesia and Australia in which these centres
are located. In order to concentrate resources
on those areas that are most vulnerable, the
International Union for the Conservation of
Nature and Natural Resources (IUCN) has
identified certain areas as biodiversity hotspots
(Figure 16.5).  Hotspots are defined according
to their vegetation.  Plants are important
because these determine the primary
productivity of an ecosystem.  Most, but not all,
of the hotspots rely on species-rich ecosystems
for food, firewood, cropland, and income from
timber.  In Madagascar, for example, about 85
per cent of the plants and animals are
found nowhere else in the world, Other
hotspots in wealthy countries are facing
CONSERVATION OF BIODIVERSITY
Biodiversity is important for human existence.
All forms of life are so closely interlinked that
disturbance in one gives rise to imbalance in
the others. If species of plants and animals
become endangered, they cause degradation
in the environment, which may threaten
human being’s own existence.
There is an urgent need to educate people
to adopt environment-friendly practices and
reorient their activities in such a way that our
development is harmonious with other life forms
and is sustainable. There is an increasing
consciousness of the fact that such conservation
with sustainable use is possible only with the
involvement and cooperation of local
communities and individuals. For this, the
development of institutional structures at local
levels is necessary. The critical problem is not
merely the conservation of species nor the
habitat but the continuation of process of
conservation.
The Government of India along with 155
other nations have signed the Convention of
Biodiversity at the Earth Summit held at
Rio de Janeiro, Brazil in June 1992. The world
Figure 16.4 : Humbodtia decurrens Bedd — highly rare
endemic tree of Southern Western Ghats (India)
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BIODIVERSITY AND CONSERVATION 139
EXERCISES
1. Multiple choice questions.
  (i) Conservation of biodiversity is important for :
(a) Animals (c) Plants
(b) Animals and plants (d) All organisms
 (ii) Threatened species are those which :
(a) threaten others
(b) Lion and tiger
(c) are abundant in number
(d) are suffering from the danger of extinction
(iii) National parks and sanctuaries are established for the purpose of :
(a) Recreation (c) Pets
(b) Hunting (d) Conservation
Figure 16.5 : Ecological ‘hotspots’ in the world
different types of pressures. The islands of
Hawaii have many unique plants and animals
that are threatened by introduced species and
land development.
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