Meaning of biodiversity
Biodiversity is the variety and variability of living organisms and how these change from one location to another and over time. Biodiversity includes diversity within species ( genetic diversity) , between species ( species diversity ) and between ecosystems ( ecosystem diversity ) . The science of biodiversity orginates largely from Ecology ( the study of relationship between organisms and their environment ) and Evolution ( the study of the origin of diversity). Biodiversity has evolved over the last 3.8 billion years or so, of the planets approximately 5 billion year history.
Distribution of biodiversity
Biodiversity is essentially everywhere on earth’s surface. It is present everywhere covering all genes, animals and plant species, ecosystems and landscapes. It includes forests, freshwater, marine and temperate environments, the soil, crop plants, domestic animals, wild species and microorganisms.
Importance of Biodiversity
People rely on biodiversity in their daily lives, often without realizing it. Biodiversity contributes to many aspects of people’s livelihoods and well-being. It ensures the survival of human species by providing food, fuel, shelter, medicines and other resources to mankind (biological resources ). Indirectly biodiversity serves the humans , by providing the basic life support systems such as clean air, water and fertile soil (ecosystem services). Over the ages, human race used plants and animals as icons to establish cultural identity ( Social benefits).
Organization of biodiversity
Biodiversity covers the diversity of life on all hierarchical levels, the diversity within species ( genetic level ), between species ( Species level ) and the variability of habitats ( ecosystem level ). Its complexity is measured in terms of variations at gnetic, species and ecosystem levels. It also includes diversity in abundance such as ( the number of genes, individuals, population or habitats in a particular location), distribution ( across location and through time) and in behaviour including interaction among the components of biodiversity.
Number of species
According to some estimates , there could be as many as 30-50 million species on Earth 90% of them occurring in tropical ecosystems. About 1.7 million of Earth’s species have been identified and designated with a scientific name. About 6% of the identified species live in polar regions, 59% in the temperate zones and the remaining 35% in the tropics.
Extinction of biodiversity
Some studies show that about one of eight known plant species is threatened with extinction. Every year, between 17,000 and 100,000 species vanish from our planet. Some people say upto 1/5 of all living species could disappear within 30 years.
Threats of Biodiversity
Currently, population growth and patterns of consumption are the most important drivers affecting biodiversity. Human-caused changes include Habitat loss, over exploitation of plant and animal species, air and water pollution, introduction of non-native species, large-scale agriculture and forestry and global climate change.
Ø economic value of biodiversity lost or threatened !
Ø ‘ ecological Services ‘ lost or threatened !
Conservation of biodiversity in India
Approximately 4.2% of the total geographical area of the country has been earmarked for extensive in-siter conservation of habitats and ecosystems through protected area network of 85 National Parks and 448 Wildlife Sanctuaries.
There are about 70 Botanic Gardens including 33 University Botanic Gardens. Also there are 275 centres in the form of zoos, deer parks, safari, parks, aquaria etc.
Global initiatives on Biodiversity conservation
The World conservation union, World Resources Institute and United Nations Environment Programme are three important agencies, whose mandates center on the conservation of the world’s Biodiversity. There have developed the ‘Global Biodiversity Strategy’ an international programme to help protect Biodiversity.
The broad objectives are to:
- Preserve Biodiversity
- Maintain Earth’s ecological processes and life-support systems
- Ensure that natural resources will be sustainably used by humans.
How Biodiversity reflects the health of the Biosphere?
The greater the variety of species , the healthier the biosphere is
- more species = more links in food chains = more stable
- more plants = better chances for survival through adaptation
- a variety of ecosystems = more habitat for different species.
“ Biodiversity keeps the planet habitable and ecosystems fuctional “- Peter Raven, A Biologist