Download Biodiversity Dr.HSNiranjanaradhya Sree Siddaganga College

Biodiversity
Dr.H.S.Niranjanaradhya
Sree Siddaganga College TUMKUR
The biodiversity or biological diversity refers to the totality of genes, species and
ecosystems of a region. The term biodiversity was coined by Walter and Rosen in 1985.
There are three Types of biodiversity namely Genetic biodiversity, Species biodiversity
and habitat or Ecosystem biodiversity.
1. Genetic diversity: The variation of genes within species is known as Genetic diversity.
No two individuals are alike. There will be structural, functional or behavioural differences.
These are basically because of the difference in the structure of genes, alleles or chromosomes.
For example there are about 4000 genes in Escherichia coli, 13000 in Drosophila melanogaster,
32000-50000 in Oriza sativa and 35000 to 45000 in Homo sapiens .
Significance: Genetic diversity enables a population to adapt to its environment and to respond
to natural selection
2. Species diversity: The variety of species present within a region is referred as species
diversity.
Significance: Every species has a specific role in an ecosystem.
The simplest method of measuring species diversity is species richness. It refers to the number
of species per unit area. The known and described number of species is between 1.7 and 1.8
million. The species diversity is more in tropical countries. The Tropical rain forests have more
than fifty percent of the species that exist in the earth.
3. Ecosystem or habitat diversity: The different kind of ecosystems present in a region is
referred as ecosystem diversity. There are two major kinds of ecosystems namely aquatic
ecosystem and terrestrial ecosystem. The aquatic ecosystem is classified into marine
ecosystem and freshwater ecosystem. The marine ecosystem has littoral ecosystem. Open sea
ecosystem, deep-sea ecosystem etc.
The fresh water ecosystem includes lentic and lotic ecosystems. The lentic ecosystems include
the standing water bodies like ponds, lakes, tanks and reservoirs. The lotic ecosystems
include flowing water ecosystems like streams and rivers.
Terrestrial ecosystems includes forests, deserts, grass land, open land, agriculture land etc.
The forests include evergreen forests, semi evergreen forests, deciduous forests, scrub jungles
etc.
Significance: Ecosystems are considered as cradles for origin of new species. They are the
laboratories of nature where experiments are conducted for the development of varieties and
new species.
Types of ecosystem biodiversity: Diversity at the level of ecosystems has three types namely
alpha diversity, beta diversity and gamma diversity. The diversity of organisms sharing the same
habitat is known as alpha diversity. The rate of replacement of species along a gradient of
habitats is known as beta diversity. The diversity of habitats over the total landscape or
geographical area is known as gamma diversity.
Megadiverse nations: Biodiversity is not evenly distributed among the world’s nations. The countries
that lie partly or entirely in tropics account for 60 to 70 percent of the world’s biodiversity are called
Megadiverse nations. There are twelve megadiverse nations in the world. They are Brazil, China,
Colombia, Ecuador, Peru, Mexico, Zaire, Madagascar, Australia, India, Indonesia and Malaysia.
The species that are present only in specific geographic area are called endemic species. Ex: Red panda
of India. Lion tailed macaque.
The species that are found in less numbers and are in the verge of extinction are called endangered
species. Ex: Tiger, lion.
The species that have disappeared from the surface of the earth are called extinct species. Ex: Dodo,
Dinosaurs.
The species that are important in determining the ability of large number of other species to persist in
the community or ecosystem are called keystone species. Ex: flying fox, tiger.
Hot spots of biodiversity: Norman Myer defined biodiversity hotspot in 1988. According to him a
region must support 1,500 endemic plant species or 0.5 percent of the global total. To qualify as a
hotspot, a region must have lost more than 70 percent of its original habitat.
There are 25 hotspots of biodiversity in the world and they contain 44 percent of all species and 35
percent of all terrestrial vertebrate species in only 1.4 percent of the planet’s land area. India has two
hot spots of biodiversity namely western Ghats and eastern Himalayas.
Benefits of biodiversity: the important benefits are economic, ecological, aesthetic and medicinal
benefits.
Economic benefits- biodiversity provides food, clothing and useful products like fuel, fiber, furniture,
scents, medicines ,energy need, fodder, agriculture , industry, sustenance to rural and tribal people.
Quinine is extracted from cinchona tree and it is used to cure Malaria. From Rosy periwinkle
vincristine medicine is prepared which is used to cure Blood Cancer. Many wild plants may have
ingredients in them to inhibit the AIDS virus. Taxol is extracted from bark of Pacific Yew which is used
to cure breast and ovarian cancer. 40% of drugs used are derived from wild sources. 25% of all
prescriptions are biological in origin.
Lesser known food plants have the potential to become the staple food plants in future. Ex: winged
been, buck wheat. Lesser known animals of food value .Ex: Insects, rats, snakes.
Ecological benefits-: Biodiversity helps in the release of O2 by plants during photosynthesis. It also
helps in soil conservation, recharge of underground water, Pollination and in maintaining Gaseous
concentration ,air and water purification, climate regulation, generation of moisture and to recycle
moisture in atmosphere.
Ethical benefits: The species that are considered as vehicles of gods or incarnation of gods are called
Sacred species. Ex: Tiger, elephant. Sacred grooves- patch of forest left untouched by the local people
due to religious myths or beliefs. Ex: Naga vana. Sacred landscapes: a patch of land or forest that is
considered as holy by local inhabitants due to religious myths or beliefs. Ex: Biligiriragana hills.
Depletion of biodiversity: Natural reasons are floods, famine, earth quakes etc. the manmade or
Anthropocentric causes are 1. Deforestation- tea, coffee plantation, construction of dams, transport
etc.2. Urbanization-depletion of habitats, natural resources 3.Agriculture- shrinking of natural
habitats, grazing, water pollution. 4.Pollution 5. Desertification- degradation of fertile land into
desert. 6.Acidification- decrease in the pH of soil and water and 7. Mining- disturbs ecosystems
Intellectual Property Rights(IPR): Legal rights to check copying of inventions, creative expressions
etc. It is an asset that could be sold, purchased, exchanged, licensed or could be donated. Ex: trade
marks, copy right, patents. WTO, GATT have promoted patents. Patent is an exclusive right granted by
govt. to an inventor or applicant for certain period of time which prevents others from making using,
selling or importing the given invention. A Patent will have usefulness, innovative and novelty.GMO’sBT Cotton, Herman bull,
Advantages –provides authenticity, economic benefit, encourages research and legal protection
Disadvantages- leads to monopoly, cannot reach the needy persons, against the law of nature, costly
procedure and does not recognize traditional knowledge.
Sustainability : Development that meets the needs of the present, without compromising the ability
of future generations to meet their needs.
TEK-knowledge or practical experience often handed down orally from generation to generation.The
collection of rainwater from surface or rooftop for storage and future use is called rainwater
harvesting. Surface water harvesting is done by the construction of bunds, percolation tanks and by
implementing the programmes of watershed development.Roof water harvesting includes steps like
collection, transport, filtering and storage of water.
Soil conservation: Methods to prevent soil erosion and to maintain the soil fertility.
Mechanical methods: 1.contour terracing-construction of channels along the slope.2.Basin listing:
construction of small basins to retain water.3.Gully control: by dams, drains or diversions 4.Bunds:
Biological methods: 1.Rotation of crops 2.Strip cropping 3.Contour farming 4.Afforestation: 5.Control
of over grazing 6.Dry land farming and 7.mulching.
Conservation of wildlife: Ex situ methods -- Seed banks, botanical, horticultural and recreational
gardens.
In situ methods–1. Protected areas-National parks, sanctuaries, biosphere reserves, and nature
reserves, reserved and protected forest. 2. Habitat preservation: a)Restoration of
habitats.b)Improvement of habitats C)Providing shelter and cover D) Artificial stocking E)Game
farming and f)Epidemic control.
Global warming: The increase in the global mean temp. due to increase in the concentration of
GHG’s.Causes: increase in CO2 concentration, CFS’s, Nitrogen oxides, Methane
Effects: on weather and climate,Increase in sea level, tropical diseases and Decrease in crop
production . Control measures: reduce emission of GHG’s , Increase vegetation cover and Use of CFC
free technology- Kyoto protocol.
Depletion of ozone layer: O3 present in stratosphere, protects us from harmful effects of UV
radiations. Causes: ODS like CFC’s, CH4, N2O
Effects: thinning in O3 thickness, Increase in skin cancer and incidence of cataract, Reduces the
functioning of immune system, Damages nucleic acids and causes genetic variations
Controlling measures: limit the production and use of ODS, and Develop and use of alternatives to
ODS. Montreal protocol.
Acid rain: The ways in which acids from atmosphere are deposited on the earth. Wet deposition or
dry deposition, less than 5.6 pH
Causes: SO2,Nitrogen oxides, CO2.
Effects: defoliation in trees, Death of aquatic organisms, Damages building materials, Burning of skin
and fabrics, Loss of soil fertility and biodiversity
Controlling measures: reduce or prevent the combustion of fossil fuels, use of alternative energy
resources, increase of vegetation cover, use of catalytic converter filters
Nuclear winter: Condition of winter cold and temperature created due to nuclear explosion.
Effects: loss of food production by crop plants, Death of plants and animals and radioactive rain.
Controlling measures: Ban on nuclear weapons and World peace movement.
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