The term biological diversity was discovered by Thomas Lovejoy (1980) and put forward by Norse & MacManus (1980).
The biodiversity term was coined by entomologist E.O. Wilson (1986). Biodiversity contains genetic diversity and ecological diversity which means sum of all the different species of animals, plants, microbes living on earths in a variety of habitat. Biologist estimated 5 to 15 million and some suggested 100 million different species inhabits the earth. Out of these 80% are microbes and arthropods.
The greatest value of biodiversity is yet unknown and scientist discovered only 20% of estimated to exist and identified which is costing 5 to 30%, GDP, 11% of world economy and 26 trillion dollars.
Species of living being are lost at alarming rates, in fact biologist estimate that 3 species go extinct everyday with a discovery of only 3 new bird species every year. Scientist around the world are cataloging and studying global diversity in hopes that they might understand it or at least slow down the rate of loss
The assembly of International Union for conservation of Nature was held at Costa Rica in Feb. 1988 While the earth submit held at Rio de Janeiro (Brazil) on 5th June 1992 was attended by 156 countries which signed 1-42 articles tor conservation of biodiversity.
The life depends on biodiversity starting from food, shelter, clothing to medical research. A human all over the world uses at least 40,000 species of plants and animals on daily basis. All of our domestic plants and animals came from wild living ancestral species. 40 percent of pharmaceutical used in USA are either based on plants, animals and microorganisms.
Heywood and Watson (1995) recorded 17 lakhs 50 thousand species on earth..Due to human activities plant and animal species are disappearing from earth at an alarming rate. The International focus on the aspect came from 1990 originating several questions regarding biodiversity:
i) Why biodiversity is essential to the health of environment.
ii) What species are disappearing particularly fast and why?
iii) What will the human behaviour for sustaining biodiversity?
However restoring biodiversity is a tough and different task. It requires diagnosis of factors responsible for deeding of species, habitat conservation, captive breeding and restriction of harvesting etc. the strategy may include:
1) Reintroduction programmes in original site of living being.
2) Augmentation programmes to increase existing population and genetic diversity of species.
3) Introduce programmes for new areas.
Any biological diversity conservation programme cannot succeed without the awareness and involvement of local people for sustainable development. The theme of the conservation must be in the sentiments of the people.
Biodiversity is a neologism from Bio and diversity. It is a measure of relative diversity a way organisms present in different ecosystems diversity within species, among species, and among ecosystems.
The totality of genes, species and ecosystems of a region these are three type of biodiversity has been observed.
1) Genetic diversity:
Variation among gene within species. The number of gene ranges from about 1000 in bacteria to more than 400000 in many flowering plants.
Each species consists of many organisms and virtually no two members of the same species are genetically identical. Genetic variation within species, both among geographically separated populations and among individual within single population
2) Species diversity:
The diversity among species includes full range of species on earth from microorganisms such as viruses, bacteria and Protists through the multicellular kingdoms of plants animals, and fungi.
3) Ecosystem diversity:
The diversity at the level of organization includes variations in the biological communities in which species live, the ecosystem in which communities exist, and the interactions among these levels. For ecologist, biodiversity is also the diversity of durable interactions among species, not only with species but also with immediate environment.
The number of species found in community is known as species richness. The biodiversity at different geographical scales are as follows:
(i) Alpha diversity (a):
Variation among one place / habitat i.e. number of species in a single community. This diversity comes closest to all popular concept of species richness arid can be used to compare the number of species in different ecosystem types.
(ii) Beta diversity (b):
Variation among habitats i.e. species composition changes along an environmental gradient.
(iii) Gamma diversity:
This applies to larger geographical scales and defined as “the rate at which additional species are encountered as geographical replacements within a habitat type in different localities”. Thus gamma diversity is a species turnover rate with distance between sites of similar habitat or with expanding areas.
Biodiversity and approaches:
1. For Biologist:
The diversity of populations of organisms and species but also the way these organisms function. Organism appears and disappears. Depending on their environment organism use the strategies of reproduction.
2. For geneticists:
The diversity of gene and organisms. They used gene mutation, exchange and dynamics that occur at DNA level and generate evolution.
3. For Ecologist:
The diversity of interactions among species. It applies for species and immediate environment (biotype) and habitat.