Cataloguing the diversity of life on earth remains one of the incomplete goals of science. Taxonomists have tried to come up with a credible number for the species that have been identified as unique — and succeeded in entering some 1.2 million in a centralised database. The problem with this number is that it is a fraction of the whole; the majority of species both on land and in the oceans has not been catalogued. It is in this context that a new species count put out by a group of scientists becomes noteworthy. Camilo Mora and colleagues propose in an open access paper titled “How Many Species Are There on Earth and in the Ocean?” (published in the journal PLoS Biology) that the number of those with complex cell structures could be 8.7 million, plus-or-minus 1.3 million. Of them, the marine species could be about 2.2 million. This estimate is a projection based on consistent and predictable patterns in the system of classifying animals and plants. The real significance lies not in the absolute number — there could be many more species, other scientists think — but in the scale of effort needed to identify and save them in a human-dominated future. Given the magnitude of the task, taxonomy as a discipline should be drawing many more researchers. It also needs massive infusions of funding.
Underpinning the estimate arrived at by Dr. Mora and his group is the thesis that there has been a definite pattern to the discovery of new classes of animals from the year 1750. Reasonable predictions were possible in the past based on the classification pyramid that scientists could build. Now, based on that model, it is suggested there may be 7.7 million species of animals, 298,000 plants, and 611,000 fungi, among others. It will take an accelerated global campaign to validate these figures. It is worth pointing out that only about 15,000 new discoveries are added to the tally annually. At the same time, the mounting resource demands of 6.9 billion humans are altering habitats at such a rapid pace that the resulting extinction rates greatly exceed the natural rates of loss. In many parts of the world, there is a fading echo of biodiversity. This demands a stronger response from governments to document life. Funding to establish more taxonomy centres in universities, for DNA analysis and for scientific expeditions, is crucial. Where funding and expertise are available, the results are impressive. Many amphibians given up as lost in India have been rediscovered and catalogued in recent years, particularly in the Western Ghats. Saving what remains of species diversity is vital, and greater understanding of what exists will help make that possible.