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Biodiversity is the variety and differences among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are a part.
It is virtually synonymous with “Life on earth”.
Biologists most often define "biological diversity" or "biodiversity" as the "totality of genes, species, and ecosystems of a region".
The biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution.
Levels of Biodiversity:
1) Genetic diversity:
It is a level of biodiversity that refers to the total number of genetic characteristics in the genetic makeup of a species.
It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.
2) Species diversity:
It refers to the variety of species within a region.
Species diversity is an index that incorporates the number of species in an area and also their relative abundance.
It is generally a much more useful value than species richness.
3) Community and Ecosystem diversity:
Ecosystem diversity refers to the diversity of a place at the level of ecosystems. This has 3 perspective:
Alpha Diversity: Within community diversity. Alpha diversity refers to the diversity of organisms sharing the same Community/Habitat.
Beta Diversity: Between community diversity. It refers to the diversity of organisms sharing two habitat.
Gamma Diversity : Diversity of the habitat over the total landscape or geographical area is called gamma diversity
Values of Biodiversity:
Food: About 80,000 edible plants and about 90% of present day food crops have been domesticated from wild.
Drugs & Medicines: About 75% of world’s population depend on plants or plant extracts.
Fuel: Forests have been used since ages for fuel wood. Fossil fuels are also products of Biodiversity.
Social Value: Many of the plants like Tulsi, Lotus, Peepal etc are considered holy and sacred.
About 2.1 million species have been identified till date, while many more species are believed to exist.
According to UNEP estimate, approximately 9.0 – 52 million of species exist on Earth
India’s position is 10th in the world & 4th in Asia in terms of Plant diversity.
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Biodiversity is derived from bios means life and diversity means variety refers to wide variety of life on earth to all plants, animals and micro organisms.
Biodiversity is defined “as the variety and variability among living organisms and the ecological complexes in which they occur.
The science of biodiversity originates largely from ecology (the study of the relationship between organisms and their environment) and evolution (the study of the origin of diversity).
The science of biodiversity originates largely from ecology (the study of the
relationship between organisms and their environment) and evolution (the
study of the origin of diversity).
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The great variety of life on earth has provided
for man’s needs over thousands of years. This
diversity of living creatures forms a support sys-
tem which has been used by each civilization
for its growth and development. Those that used
this “bounty of nature” carefully and sustainably
survived. Those that overused or misused it dis-
What is biodiversity?
Biological diversity deals with the degree of
nature’s variety in the biosphere. This variety can
be observed at three levels; the genetic variabil-
ity within a species, the variety of species within
a community, and the organisation of species
in an area into distinctive plant and animal com-
munities constitutes ecosystem diversity.
‘Biological diversity’ or biodiversity is that part
of nature which includes the differences in genes
among the individuals of a species, the variety
and richness of all the plant and animal species
at different scales in space, locally, in a region,
in the country and the world, and various types
of ecosystems, both terrestrial and aquatic,
within a defined area.
BIOGEOGRAPHIC CLASSIFICATION OF
Our country can be conveniently divided into
ten major regions, based on the geography, cli-
mate and pattern of vegetation seen and the
communities of mammals, birds, reptiles, am-
phibia, insects and other invertebrates that live
in them. Each of these regions contains a vari-
ety of ecosystems such as forests, grasslands,
lakes, rivers, wetlands, mountains and hills,
which have specific plant and animal species.
Keeping future possibilities open for their use is
called option value. It is impossible to predict
which of our species or traditional varieties of
crops and domestic animals will be of great use
in the future. To continue to improve cultivars
and domestic livestock, we need to return to
wild relatives of crop plants and animals. Thus
the preservation of biodiversity must also include
traditionally used strains already in existence in
crops and domestic animals.
HOTSPOTS OF BIODIVERSITY
The earth’s biodiversity is distributed in specific
ecological regions. There are over a thousand
major ecoregions in the world. Of these, 200
are said to be the richest, rarest and most dis-
tinctive natural areas. These areas are referred
to as the Global 200.
It has been estimated that 50,000 endemic
plants which comprise 20% of global plant life,
probably occur in only 18 ‘hot spots’ in the
world. Countries which have a relatively large
proportion of these hot spots of diversity are
referred to as ‘megadiversity nations’.