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Biodiversity notes

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Biodiversity, environmental study

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Conservation of Biological Diversity
(Biodiversity Conservation)
(NOTES)
Definition: Biodiversity is defined as the variety and variability among all
groups of living organisms and the ecosystem in which they live.

Significance of biodiversity

1. Biodiversity protects the fresh air, clean water and productive land.
2. It is also important for forestry, fisheries and agriculture, which depend
on rich water variety of various biological resources available in nature.

3. Loss of biodiversity exerts heavy economic and social costs for any
country.

4. It is very important for human life; we depend on plants, microorganisms
and earth’s animals for our food, medicine and industrial products.

Biodiversity is usually considered at 3 different levels

1. Genetic diversity
2. Species diversity
3. Ecosystem diversity

(1) Genetic diversity: Genes are the basic unit of hereditary information,
transmitted from one generation to the other. Within individual species, there
are a number of varieties, which are slightly different from one another. These
differences are due to difference in the combination of genes.

Example: all rice varieties belong to the species “Oryza sativa”; but there are
thousands of wild and cultivated varieties of rice, which shows variations at the
genetic level and are different in their colour, size, shape, nutrient content of
the plant.

(2) Species diversity: A discrete group of organisms of the same kinds is known
as species. Species diversity is the diversity between different species. The sum

, 2


of varieties of all the living organisms at the species level is known as species
diversity.

Example: There are more than 20 million organisms on the earth,which have
been identified and given names. Apple, mango, grapes, wheat, rice, etc. are
examples of plant species.

(3) Ecosystem diversity: It is a set of biotic components [such as plants,
animals and micro organisms] interacting with one another and with abiotic
components[such as soil, air, water, etc.]. The diversity at the ecological or
habitat level is known as “ecosystem diversity”. A large region with different
ecosystems can be considered as ecosystem diversity. The ecosystem also
shows variation with respect to physical parameters like moisture,
temperature, altitude, precipitation, etc.

Example: Forest ecosystem is supposed to have mainly dominance of trees.
But, while considering a tropical rain forest, a tropical deciduous forest and a
temperature forest, variations observed are numerous due to variations in the
physical factors.

Biogeographical classification of India

India is a mega diversity country having different types of climate and
topography in different parts of the country. These variations have induced
much variability in flora and fauna. India occupies 10th position among the
plant-rich countries of the world.

It is a very important to know and study the distribution, elevation and
environmental relationship of plants and animals in time and space.

Biogeography: It comprising of photo-geography and zoo-geography, which
deals with aspects of plants and animals, respectively. In order to know about
the distribution and environmental interaction of flora and fauna of our
country, it has been classified into 10 bio-geographical zones. Each of these
zones has its own climate and soil topography(shape and features of the earth)
and biodiversity.

, 3


Global biodiversity

Following the 1992 “earth summit” at Rio de Janeiro (Brazil) , it became
evident that there is a growing need to know about the huge number of
species, which are still unknown on this earth.

Roughly 1.5 million species are known till today, which is perhaps 15% of the
actual number of the total earth-biodiversity. It has, therefore, been rightly
recognized as an emergency task in order to plan its conservation and practical
utilization.

Terrestrial biodiversity of the earth is best described as “biomass”, which is the
largest ecological unit present in different geographic areas.

Example: Tropical rain-forests are inhabited by millions of species of plants,
birds, amphibians, insects and mammals. They are the earth’s largest store
house of biodiversity. About 50-80% of global biodiversity lies in these rain-
forests.3,000 plants, identified by national cancer research institute [NCRI], are
marvellous sources of cancer fighting chemicals.

Very recently extract from one of the creeping wines in the rain forests at
Cameroon has proved effective in the inhibition of replication of ‘AIDS’ virus.

Tropical forests have much less biodiversity, but there is much better
documentation of the species at global level, representing about 170,000 of
flowering plants, 30,000 of vertebrates and about 250,000 of other groups of
species.

Biological diversity at national level

Every country is characterised by its own biodiversity depending mainly on its
climate.

1. India has a rich biological diversity of flora and fauna, representing about
6% of the global biodiversity.

2. India ranks 10th among the plant-rich countries of the world, 11th in term
of number of endemic species of high vertebrates and 6th among the
centres of diversity and origin of agricultural crops

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Publié le
25 juillet 2023
Nombre de pages
22
Écrit en
2022/2023
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Notes de cours
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