Life in numbers

Man often forgets that he is an animal, one of the countless numbers of species that inhabit Planet Earth. Indeed, the world would be very dull and uninspiring if only Man existed. Thanks to the evolution of life on Earth, we have plenty of other living things, plants and animals, for company. Living things come in all shapes and sizes. From the blue whale to the amoeba, from a tiny seedling to the giant coniferous coast redwood tree, the sheer variety of life is astounding.

In the air, on the ground, under the ground, in rivers and oceans and in some of the most extreme environments in the plant, life thrives. This biodiversity is an asset that we must protect. But exactly how many species exist on Earth ? Estimates have varied widely, though one thing is well known:

There are species out there we know nothing about. Biologically speaking, we have barely explored life on Earth. There are millions of species waiting to be discovered and scientifically categorised.

It is in this backdrop that we find the latest discovery by a group of researchers rather interesting: They have concluded that there could be around 8.7 million species on Earth. Although the number is still an estimate, it represents the most rigorous mathematical analysis yet of what we know - and don't know - about life on land and in the sea.

The authors of the paper, published last week by the respected scientific journal PLoS Biology, suggest 86 percent of all terrestrial species and 91 percent of all marine species have yet to be discovered, described and catalogued.

Gap in knowledge

That is a huge gap in our knowledge of the natural world. As the authors of the study point out, the new analysis is significant not only because it gives more detail on a fundamental scientific mystery, but also because it helps capture the complexity of a natural system that is in danger of losing species at an unprecedented rate.

Five academics in the research team refined the number by compiling taxonomic data for roughly 1.2 million known species and identifying numerical patterns. They saw that within the best-known groups, such as mammals, there was a predictable ratio of species to broader categories. They applied these numerical patterns to all five major kingdoms of life, which excludes micro-organisms and virus types.

The researchers predicted there are about 7.77 million species of animals, 298,000 plants, 611,000 fungi, 36,400 protozoa and 27,500 chromists (which include various algae and water molds). Only a fraction of these species have been identified yet, including just 7 percent of fungi and 12 percent of animals, compared with 72 percent of plants. Marine biologist Boris Worm of Canada's Dalhousie University, one of the paper's co-authors, has compared the planet to a machine with 8.7 million parts, all of which perform a valuable function.

"If you think of the planet as a life-support system for our species, you want to look at how complex that life-support system is," Worm said. "We're tinkering with that machine because we're throwing out parts all the time." Indeed, species are becoming extinct at an alarming rate, even as new ones are being discovered.

Tip of the iceberg

But we are touching the tip of the iceberg here. According to the International Union for Conservation of Nature (IUCN), a large number of species face the threat of extinction, but their survey monitors less than one percent of the world's species.

This raises the sad prospect of species vanishing within our lifetimes without us even knowing anything about them. There cannot be a more appropriate occasion for the saying "from oblivion to obscurity". It is thus important to step up efforts to search for new species.

Searching for new species is no easy task. It takes a lot of time, patience and of course, money. The latter is one factor that inhibits more biological research. This is especially so in the case of developing countries which are faced with far more pressing issues concerning their (human) population.

But that does not mean that research on new and existing forms of life should be overlooked. After all, many discoveries in the sphere of biology have ultimately benefitted humans.

For example, many medicines are actually based on plant materials and extracts. Saving endangered species is vital to humanity and to the Earth itself, because every species has a role to play in the biosphere. Sri Lanka is known as one of the few countries with a very high degree of biodiversity including endemic species.

Every year, new species of animals and plants are discovered especially in our jungles. Among them are said to be plants with unique genetic traits and even medicinal properties. However, most research into our endemic species is conducted by foreign researchers with or without the collaboration of local researchers. Sri Lankans get to know about the results only when their papers are published in foreign journals such as Nature. There should be more local research on our biodiversity, with the active participation of universities. Zoos around the world, including the one in Sri Lanka, have a major role to play in stopping the extinction of endangered species. Captive breeding could be the only solution available to save certain animals from being lost forever.

This is an urgent mission - a new study has shown that 20 percent of the nearly 5,500 mammalian species alone are at risk. Other animal groups fare no better.

The Dodo is only a picture now. Should the Siberian Tiger too become just a picture in less than 50 years ? This is where we should intervene. Life will find a way, but sometimes a little push is welcome. It is in this context that the new study on the number of species gains importance.

It shows us that life on earth is 'bigger' and more precious than we can ever imagine. It also indicates the need for actively pursuing research on new species and preserving the species that could be lost. Life deserves a second chance.