Navas cheemadan
(including algae, fungi, bryophytes,
Biodiversity and Conservation gymnosperms and angiosperms) comprise
no more than 22 per cent of the total.
Biodiversity • Among animals, insects are the
most species-rich taxonomic group,
There are more than 20,000 making up more than 70 per cent of the
species of ants, 3,00,000 species of total (it means that, out of every 10
beetles, 28,000 species of fishes and nearly animals on this planet, 7 are insects.)
20,000 species of orchids. • The number of fungi species in
Biodiversity is the term popularized the world is more than the combined
by the sociobiologist Edward Wilson to total of the species of fishes,
describe the combined diversity at all the amphibians, reptiles and mammals.
levels of biological organization • The number of fishes among
Biodiversity can be described as the vertebrates are more than total number
sum total of genes, species and of mammals, Birds, reptiles and
ecosystem of a region Amphibians !
(i) Genetic diversity • Biologists are not sure about how
A single species might show high many prokaryotic species there might be
diversity at the genetic level over its India has only 2.4 per cent of the world’s
distributional range land area, its share of the global species
Eg: The genetic variation shown by the diversity is an impressive 8.1 per cent. (
medicinal plant Rauwolfia vomitoria This makes our country one of the 12
growing in different Himalayan ranges mega diversity countries of the world.)
might be in terms of the potency and • Nearly 45,000 species of plants and
concentration of the active chemical twice as many of animals have been
(reserpine) that the plant produces. recorded from India.
• India has more than 50,000 ➢ If we accept May’s global estimates,
genetically different strains of rice, and only 22 per cent of the total species have
1,000 varieties of mango. been recorded so far. Applying this
(ii) Species diversity: proportion to India’s diversity figures, we
The diversity at the species level. estimate that there are probably more than
Eg: the Western Ghats have a greater 1,00,000 plant species and more than
amphibian species diversity than the 3,00,000 animal species yet to be
Eastern Ghats. discovered and described !
(iii) Ecological diversity:
The diversity at the ecosystem level. Patterns of Biodiversity
Eg: India has variety of ecosystem like (i) Latitudinal gradients:
deserts, rain forests, mangroves, coral The diversity of plants and animals
reefs, wetlands, estuaries, and alpine is not uniform throughout the world.
meadows has a greater ecosystem In general, species diversity decreases as
diversity than a Scandinavian country like we move away from the equator towards
Norway. the poles.
How Many Species are there on With very few exceptions, tropics
Earth and How Many in India? (latitudinal range of 23.5° N to 23.5° S)
According to the IUCN (2004), the harbour more species than temperate or
total number of plant and animal species polar areas.
described so far is slightly more than 1.5 ➢ Colombia located near the equator
million. has nearly 1,400 species of birds while New
According to Robert May total the York at 41° N has 105 species and
global species diversity Is about 7 million. Greenland at 71° N only 56 species. India,
• More than 70 per cent of all the with much of its land area in the tropical
species recorded are animals, while plants
1
, Navas cheemadan
latitudes, has more than 1,200 species of
birds.
➢ A forest in a tropical region like
Equador has up to 10 times as many
species of vascular plants as a forest of
equal area in a temperate region like the
Midwest of the USA.
➢ The largely tropical Amazonian rain
forest in South America has the greatest
biodiversity on earth- it is home to more
than 40,000 species of plants, 3,000 of
fishes, 1,300 of birds, 427 of mammals, 427
of amphibians, 378 of reptiles and of more
than 1,25,000 invertebrates. Scientists log S = log C + Z log A
estimate that in these rain forests there where
might be at least two million insect S= Species richness A= Area
species waiting to be discovered and Z = slope of the line (regression
named !!!! coefficient)
Reason for the great diversity in the C = Y-intercept
tropical regions ✓ Ecologists have discovered that the
(1) Tropical regions have remained value of Z lies in the range of 0.1 to 0.2,
relatively undisturbed for millions of years regardless of the taxonomic group or the
and thus had a long time for species region (whether it is the plants in Britain,
diversification. birds in California or molluscs in New York
(2) Tropical environments, unlike state, the slopes of the regression line are
temperate ones, are less seasonal, amazingly similar)
relatively more constant and predictable. ✓ The species-area relationships
Such constant environments promote among very large areas like the entire
niche specialisation and lead to a greater continents, you will find that the slope of
species diversity. the line to be much steeper (Z values in
(3) There is more solar energy available in the range of 0.6 to 1.2).
the tropics, which contributes to higher For example, for frugivorous (fruit-
productivity; this in turn might contribute eating) birds and mammals in the tropical
indirectly to greater diversity. forests of different continents, the slope is
(ii) Species-Area relationships: found to be 1.15
According to German naturalist and
geographer Alaxander Von Humboldt, The importance of Species Diversity to
species richness increased with increasing the Ecosystem
explored area,but only upto a limit. The A community with more
relationship between species richness and species tend to be more stable than those
area for a wide variety of taxa (angiosperm with less stable.
plants, birds, bats, freshwater fishes) turns A community which should not show
out to be a rectangular hyperbola. On a too much variation in productivity from
logarithmic scale, the relationship is a year to year called Stable community.
straight line described by the equation Such community are resistant to
occasional disturbance ( natural or man
made) and resistant to alien species
invasion.
David Tilman conducted some long term
experiments using outdoor plots,
explained that increased diversity
contributed to higher productivity. Rich
diversity and higher productivity are not
2
(including algae, fungi, bryophytes,
Biodiversity and Conservation gymnosperms and angiosperms) comprise
no more than 22 per cent of the total.
Biodiversity • Among animals, insects are the
most species-rich taxonomic group,
There are more than 20,000 making up more than 70 per cent of the
species of ants, 3,00,000 species of total (it means that, out of every 10
beetles, 28,000 species of fishes and nearly animals on this planet, 7 are insects.)
20,000 species of orchids. • The number of fungi species in
Biodiversity is the term popularized the world is more than the combined
by the sociobiologist Edward Wilson to total of the species of fishes,
describe the combined diversity at all the amphibians, reptiles and mammals.
levels of biological organization • The number of fishes among
Biodiversity can be described as the vertebrates are more than total number
sum total of genes, species and of mammals, Birds, reptiles and
ecosystem of a region Amphibians !
(i) Genetic diversity • Biologists are not sure about how
A single species might show high many prokaryotic species there might be
diversity at the genetic level over its India has only 2.4 per cent of the world’s
distributional range land area, its share of the global species
Eg: The genetic variation shown by the diversity is an impressive 8.1 per cent. (
medicinal plant Rauwolfia vomitoria This makes our country one of the 12
growing in different Himalayan ranges mega diversity countries of the world.)
might be in terms of the potency and • Nearly 45,000 species of plants and
concentration of the active chemical twice as many of animals have been
(reserpine) that the plant produces. recorded from India.
• India has more than 50,000 ➢ If we accept May’s global estimates,
genetically different strains of rice, and only 22 per cent of the total species have
1,000 varieties of mango. been recorded so far. Applying this
(ii) Species diversity: proportion to India’s diversity figures, we
The diversity at the species level. estimate that there are probably more than
Eg: the Western Ghats have a greater 1,00,000 plant species and more than
amphibian species diversity than the 3,00,000 animal species yet to be
Eastern Ghats. discovered and described !
(iii) Ecological diversity:
The diversity at the ecosystem level. Patterns of Biodiversity
Eg: India has variety of ecosystem like (i) Latitudinal gradients:
deserts, rain forests, mangroves, coral The diversity of plants and animals
reefs, wetlands, estuaries, and alpine is not uniform throughout the world.
meadows has a greater ecosystem In general, species diversity decreases as
diversity than a Scandinavian country like we move away from the equator towards
Norway. the poles.
How Many Species are there on With very few exceptions, tropics
Earth and How Many in India? (latitudinal range of 23.5° N to 23.5° S)
According to the IUCN (2004), the harbour more species than temperate or
total number of plant and animal species polar areas.
described so far is slightly more than 1.5 ➢ Colombia located near the equator
million. has nearly 1,400 species of birds while New
According to Robert May total the York at 41° N has 105 species and
global species diversity Is about 7 million. Greenland at 71° N only 56 species. India,
• More than 70 per cent of all the with much of its land area in the tropical
species recorded are animals, while plants
1
, Navas cheemadan
latitudes, has more than 1,200 species of
birds.
➢ A forest in a tropical region like
Equador has up to 10 times as many
species of vascular plants as a forest of
equal area in a temperate region like the
Midwest of the USA.
➢ The largely tropical Amazonian rain
forest in South America has the greatest
biodiversity on earth- it is home to more
than 40,000 species of plants, 3,000 of
fishes, 1,300 of birds, 427 of mammals, 427
of amphibians, 378 of reptiles and of more
than 1,25,000 invertebrates. Scientists log S = log C + Z log A
estimate that in these rain forests there where
might be at least two million insect S= Species richness A= Area
species waiting to be discovered and Z = slope of the line (regression
named !!!! coefficient)
Reason for the great diversity in the C = Y-intercept
tropical regions ✓ Ecologists have discovered that the
(1) Tropical regions have remained value of Z lies in the range of 0.1 to 0.2,
relatively undisturbed for millions of years regardless of the taxonomic group or the
and thus had a long time for species region (whether it is the plants in Britain,
diversification. birds in California or molluscs in New York
(2) Tropical environments, unlike state, the slopes of the regression line are
temperate ones, are less seasonal, amazingly similar)
relatively more constant and predictable. ✓ The species-area relationships
Such constant environments promote among very large areas like the entire
niche specialisation and lead to a greater continents, you will find that the slope of
species diversity. the line to be much steeper (Z values in
(3) There is more solar energy available in the range of 0.6 to 1.2).
the tropics, which contributes to higher For example, for frugivorous (fruit-
productivity; this in turn might contribute eating) birds and mammals in the tropical
indirectly to greater diversity. forests of different continents, the slope is
(ii) Species-Area relationships: found to be 1.15
According to German naturalist and
geographer Alaxander Von Humboldt, The importance of Species Diversity to
species richness increased with increasing the Ecosystem
explored area,but only upto a limit. The A community with more
relationship between species richness and species tend to be more stable than those
area for a wide variety of taxa (angiosperm with less stable.
plants, birds, bats, freshwater fishes) turns A community which should not show
out to be a rectangular hyperbola. On a too much variation in productivity from
logarithmic scale, the relationship is a year to year called Stable community.
straight line described by the equation Such community are resistant to
occasional disturbance ( natural or man
made) and resistant to alien species
invasion.
David Tilman conducted some long term
experiments using outdoor plots,
explained that increased diversity
contributed to higher productivity. Rich
diversity and higher productivity are not
2
