(1) The wide range of microorganisms, algae, fungi, plants, and animals that inhabit the planet, regardless of whether they are found on land or in water, and the ecological complexes that they are part
(2) The diversity ranges from macromolecules to biomes.
(3) Organization of biodiversity on earth at three levels:
(i) Genetic diversity.
(il) Species diversity
(4) Genetic diversity
(i) It relates to the variations of genes within species.
(ii) Variations may be in different variants of the same genes (alleles), or in whole genes or chromosomes
(iii) The higher the genetic diversity among organisms of a species, the more resilient it is against environmental perturbations.
(iv) Diseases are more likely to spread in genetically homogeneous populations.
(5) Species diversity
It has to do with the variety of species within a region.
(ii) Species richness is the number of species per unit area.
In (iii) Species Evenness, the relative abundance of each species is taken into consideration
in an area.
Biodiversity in India
(1) India is one of twelve countries with mega biodiversity.
(2) India has 10 biogeographical regions, 89 national parks, 500 wildlife sanctuaries, 14
biosphere reserves, 6 westlands and 35 world heritage sites.
(3) There are about 45,000 species of plants and about 90,000-1,00,000 species of animals.
Patterns of Biodiversity
(1) Biodiversity changes with change in latitude or altitude.
(2) It is minimum at the poles and maximum near or at equator. Similarly, as one moves down from higher to lower altitudes, biodiversity is increased.
Loss of biodiversity:
(1) Caused by three factors - Population, Urbanization and Industrialisation.
(2) The colonization of tropical Pacific Islands by human has led to the extinction of more than 2000 species of native birds.
(3) Loss of biodiversity in a region leads to:
(i) decrease in plant production.
(ii) less resistance to environmental disturbances such as droughts.
(iii) increase in variability in ecosystem processes like plant productivity, water use, pest
and disease cycles etc.)
Biodiversity Conservation
In situ conservation in their
(1) Conservation of and protection of the total ecosystem and its biodiversity through a network of protected areas is the most appropriate strategy to preserve species of wild animals and plants in their natural habitats.
(2) The common natural habitats (protected areas) that have been set for in-situ conservation of wild animals and plants include:
(i) National parks
(ii) Wild life sanctuaries
(iii) Biosphere reserves.
(iv) Several wetlands, mangroves and coral reefs,
(v) Sacred groves and lakes.
(3) Hotspot of biodiversity are those regions of rich biodiversity which have been declared
sensitive due to direct or indirect interference of human activities.
(4) There are 25 terrestrial hotspots in the world including two from India.
Ex situ conservation
(1) Threatened animals and plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care.
(2) Ex situ conservation includes the following:
(i) Sacred plants and home gardens
(ii) Seed banks, field gene banks, cryopreservation.
(ii) Botanical gardens, Arborata, Zoological gardens, Aquaria.
Convention on Biodiversity:
(1)During the Earth Summit held in Rio de Janeiro in 1992, all nations were encouraged to undertake measures to conserve biodiversity and ensure sustainable use of resources.
(2)An international conference on sustainable development took place in Johannesburg, South Africa, in 2002, where 190 countries pledged their commitment to reduce by 2010 the current rate of biodiversity loss at the global, regional, and local levels.