Biodiversity has now become a very important
term of general discussion among the common learneds. This scientific term has become common because of its importance for everyone at every walk of life. The term biological diversity was first of all brought in to light by Norse and McManus in 1980 and the two terms were articulated as a single term “
Biodiversity” by W.G. Rosen in 1985. The term biodiversity comprises of all the living components
present on, in or around the Earth ranging from sub-microscopic to microscopic level. Our Earth supports something like 5-10 million species of
plants and animals which have been the result of 3 billion years of evolution involving mutation, recombination and natural selection. Changing environments like Ice age followed by Warm periods and even drought exerting severe selection pressures were probably responsible for evolution of new species and also for
extinction of others. The two processes have gone side by side. The present day life probably constitutes about 1% of the total that has existed on this planet so far. Every organism present on the Earth benefits the man directly or indirectly. Man has exploited various organisms for his food, cloth and shelter.
Large number of pharmaceutical products and life saving chemicals are derived from various microorganisms. About 2500 plant species have been cultivated by man; including all the microbial and wild forms used by man the figure may not cross the limit of 5000. The figure shows that still we have used even less than 0.3% of the total plant species recorded (1.5 million). So, extremely large number of species are yet to be used, and they should be, before their extinction.
Though to less extent, man has used nearly all the group of plants for its benefit, starting from bacteria and cyanobacteria to the gymnosperm and angiosperm. Progress in science and technology has opened a vista for use of even the viruses in the field of pest control and for the transfer of genome through temperate phases. Similarly, all the group of animals have also been used either as trophic substitute or clothing or for
medicinal aid. Equally important are the microorganisms which are very important components of the biosphere. Any clearance of forestland, either by removing plant cover or by Slash and burn clearing is a threat to beneficial microorganisms. If bacteria, actinomycetes and fungi were not present the complete land surface of Earth would have been converted into grave yard and no space would have been left for new burial. Large numbers of terrestrial and aquatic plants have been employed as scrubber or filter for the abatement of air and water pollution, in the favour of man. One cannot imagine a situation if Penicillium had been eliminated from the earth before Sir Alexender Fleming made use of it as an antibiotic or if Cinchona become extinct before Quinine was discovered as a cure for malaria.
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