Biodiversity Current Scenario

There is no firm consensus on exactly how many species exist on Earth or how many occur in India. Although more than 1.5 million species had been formally documented according to IUCN data as of 2004, vast numbers remain unstudied, and scientists cannot even be certain how many new species continue to arise through ongoing speciation. Most systematic study so far has focused on temperate regions, while tropical rain forests -- the planet's major hotspots of diversity -- remain far from fully explored. Some very high estimates of global species numbers (20 to 50 million) have been proposed, but the ecologist Robert May's more widely accepted estimate puts the true figure at around 7 million species worldwide (see Fig. 15.2 for the breakdown of currently known groups). Notably, these diagrams carry no data on prokaryotes, because many bacterial species cannot be cultured in the laboratory and conventional taxonomic methods are not well suited to identifying them. …