May 23, 2007

In a Class of His Own: The Man Who Named the Natural World

By Michael McCarthy

Happy anniversary: the man who gave us the key to the natural world was born 300 years ago today. Carl Linnaeus, who created the system of scientific names that we still use for all living things, began life in a turf-roofed farmstead in southern Sweden on 23 May, 1707.

If Hamlet is the world's most famous Dane, Linnaeus is the world's most famous Swede, surpassing in renown even the warrior- king Gustavus Adolphus, Strindberg, Ingmar Bergman and Abba. His face has decorated Swedish banknotes since 1894. Yet his tercentenary is being celebrated in Britain as much as in the country of his birth. Since shortly after his death, Linnaeus's library, letters, papers and specimens, which make up one of the world's great scientific treasure-troves, have been in the care of the Linnean Society of London, at Burlington House, in Piccadilly.

The King of Sweden has just visited them. The Emperor of Japan (a keen marine biologist) is about to do so. Amid many celebratory meetings and gatherings in Britain, a recent issue of Nature, the world's leading scientific journal, was given over to Linnaeus's legacy, and an exquisite Swedish garden is being devoted to his memory in this week's Chelsea Flower Show. These are timely reminders of an immense achievement.

It's those two words of Latin, the first beginning with a capital letter and the second without, printed in italics and impossible to remember for most of us, that you sometimes see following the ordinary English name of a plant, a fish, a mammal, an insect, a bird. Take the emblematic bird of the Tower of London, for instance. The raven: Corvus corax. Unnecessary, you might think, a waste of time. Why not just call it a raven and have done with it? Until you remember that in France, a raven is a grand corbeau. In the Netherlands, it's a raaf. In Germany, it's a kolkrabe, while in Linnaeus's own Sweden it's a korp, never mind what it's called as you travel across Eurasia through Finland and Russia to Japan and Korea and China. Yet a biologist from any one of them can talk about a raven to a biologist from any other, and know they are referring to the same organism, because they both accept that this member of the crow family, for which they each have a different common name, is also universally known, scientifically, as Corvus corax, the name that Carl Linnaeus bestowed upon it two-and-a-half centuries ago.

Just how important this is starts to dawn on you when you realise how great is the variety of life on Earth. There are about 10,000 bird species in the world, and about half that number of mammals. There are more than 400,000 species of plants that have so far been described, and much more than a million species of insects, with perhaps another two to three million still to be discovered. And as with species, so with languages. The Earth is a Tower of Babel, with more than 6,000 languages spoken across the globe. Alright, some may only be spoken by a single tribe. But more than 300 languages are spoken in London alone. Three hundred different words for those big black crows at The Tower? Imagine.

Even if you restricted the official naming of living things to just a dozen of the world's major tongues - let's say English, French, German, Spanish, Portuguese, Russian, Arabic, Japanese, Mandarin, Cantonese, Hindi and Bengali - the linguistic barrier to dealing with the wonderful but bewildering extent of the planet's biodiversity would be instantly insuperable. But what Linnaeus's system of scientific names has enabled human society to do is to get a hold on biodiversity and impose order on it. It has given us a framework for exploring and understanding the teeming life of the world, and we have never needed it more than now, when so much of it is increasingly threatened with extinction.

It works for two reasons. Firstly, it's in an international language. You might think Latin is dead, but in biodiversity, it's very much alive, and it offers a worldwide level playing field, without any taint of cultural imperialism. If you believe that scientific names should be in English because English is taking over everything else, try telling that to a botanist from Brazil. You'll get a dusty answer.

Secondly (and this is its brilliance) it consists of just two words, which enable the subject to be designated precisely, and in the most succinct way possible.

The first is known as the generic name, and represents the genus, or grouping of species the creature belongs to. With the raven, Corvus (the Latin word for crow) signifies the genus, which groups together black crows. The second word is known as the specific name, and marks out, within the genus, the individual species. So corax (the Greek word for raven) designates the biggest of the black crows. And by extension, in Britain we also have Corvus corone , the carrion crow; Corvus frugilegus, the rook, and Corvus monedu-la, the jackdaw. (Linnaeus named all those as well, by the way, and if you're interested, corone is Greek for crow, frugilegus is Latin for "fruit-gatherer", and mon-edula is Latin for "little money bird", perhaps from the fact that jackdaws will steal bright coins.)

The system is formally known as binomial nomenclature - "two- name naming". Linnaeus hit upon the trick while carrying out a massive and ambitious survey of all known plants, for although he eventually applied it to birds and creatures of every type, he was first and foremost a botanist - and he was one of his-tory's most eminent.

From the earliest times plants were considered the most important area of nature to know formally, because they constituted the whole basis of medicine; they provided the only drugs. But, although people had been giving plants names for thousands of years, everybody's names were different; nothing was standardised. For a millennium after the Roman Empire fell, the only serious way of thinking about plants was to consult the treatise of a first- century Greek doctor, Dioscorides, who described (in Latin) about 500 plants in terms of their medical properties - and accept what he said.

Two developments at the start of the 16th century changed all that. One was the European Renaissance - the revival of learning; the other was the discovery of the New World of the Americas. The first set loose a radical spirit of free enquiry. It prompted learned men to put Dioscorides aside and look at plants for themselves for the first time (instead of just at their medical properties) and, in so doing, to think hard about how they were constructed, how they worked, and how they were related.

The second unleashed a torrent of new plant species on Europe. Europeans had always known vines and olives and wheat; now, suddenly, they were presented with tomatoes and potatoes and tobacco, and a seemingly endless stream of other novelties. A Jesuit who accompanied Pizarro on the conquest of Peru was famously quoted as saying that the vegetable productions of the New World were so different from that of the Old that there must have been two Gardens of Eden.

Throughout the 16th and 17th centuries, Europe's plantsmen (they weren't called botanists yet) worked tirelessly at trying to bring order to a flood of new and unfamiliar species that grew and grew, for collectors were now bringing back rarities from China, Japan, India and southern Africa as well as from the Americas. The plantsmen used Latin, of course, then the undisputed international language of science and of learning; and they increasingly tended to tag each species not with a name, but a long Latin descriptive phrase ("A blue-green cabbage with a hairy stem and jagged leaves"). The trouble was that my descriptive phrase was-n't necessarily the same as your descriptive phrase for the same plant. It was almost certainly slightly different, and there was no central authority to standardise matters. Confusion reigned.

This was the situation when Linnaeus was born in a homestead at Rashult in the province of Smaland in southern Sweden; the son of the local pastor, Nils Nicolaus Linnaeus. He was intended for the church himself, but rejected that for a career in botany (as plant science had now been named by the English naturalist John Ray), getting his start at Uppsala, Sweden's (and indeed Northern Europe's) oldest university.

The student Linnaeus was befriended at Uppsala by the theologian and naturalist Olof Celsius (after whom the temperature scale is named), who appointed him demonstrator in botany in 1730. Linnaeus made an enterprising trip to Lapland in northern Sweden, writing a book about its flora, spent three years in Dutch universities, came back to marry his sweetheart Sara Moraeaus, practised medicine in Stockholm (specialising in treating venereal diseases) and took up a chair back in Uppsala in 1741, where he remained, and did the work that secured him his place in history.

The essential fact about Linnaeus is not that he was a very good botanist (although he was) nor that he was enormously productive (he was that too) but that he possessed a quite overweening intellectual ambition. Not a few historical figures have wanted to conquer the whole world; but Carl Linnaeus, the boy from the Swedish backwoods, wanted from an early age to order it intellectually. One of the great surprises of history is that he ended up doing so.

Maybe you need ego for real success in science. Although he inspired genuine devotion in his students, some of Linnaeus's pronouncements were singularly lacking in modesty. ("I have fundamentally reorganised the whole field of Natural History, raising it to the height it has now attained," he wrote when he was famous. "I doubt whether anyone today could hope, without my help and guidance, to make any advance in this field.") And he started early. In 1735, for example, he published in the Netherlands a classification of the whole of the known natural world entitled Systema Naturae ("The System of Nature").

At just 28. Aspirational or what? It's a huge but thin book, a massive set of diagrams, really, and you can gaze on it - Linnaeus's own copy - in the Linnean Society's temperature-controlled strongroom in Burlington House. You might think that the Swedes would cut up rough, like the Greeks with the Elgin Marbles, about their nation's greatest intellectual treasures being located now in London rather than Uppsala or Stockholm, but they never have. They know Linnaeus's library, papers and specimens are very well looked after where they are, and perfectly easy of access; and, also, they were bought fair and square from Linnaeus's widow, Sara. Linnaeus died in 1778; his son, who had succeeded him as Professor at Uppsala, died only five years later, and Sara instructed the family lawyer to sell the collections. They were bought in 1784 (for [pound]1,088 5s 0d) by James Edward Smith, a wealthy young Briton passionately interested in natural history, and became the rock on which the Linnean Society of London was founded, by Smith and a group of fellow enthusiasts, in 1788.

Throughout the 19th century it was one of Britain's leading scientific societies (and it was at a historic meeting of the Linnean on July 1, 1858, that Charles Darwin's theory of evolution by natural selection was given its first public airing).

In the society's strongroom you can see all Linnaeus's books, all his letters, all his preserved specimens from butterflies to fishes, and you can also see something else: his mind working towards his great idea.

I am in the strongroom with Sandy Knapp, a leading botanist from the Natural History Museum, who is the Linnean Society's botanical secretary, and she is talking to me about two related plants in which she has a particular interest - the tomato and the potato. Both belong to the genus Solanum (the nightshades), on which Sandy - calling someone so enthusiastic "Dr Knapp" seems inappropriate - is one of the world experts.

She takes down another big book, Linnaeus's 1737 catalogue of all the plants in the garden of George Clifford, an English merchant living in Holland, and finds the solanums, and points out the tomato. At that point Linnaeus calls it Solanum caule inermi annuo, foliis pinnatis incisis (nightshade with a smooth annual stem with incised pinnate [on opposite sides of the stalk] leaves). Then she finds the potato. Linnaeus calls that Solanum caule inermi annuo, foliis pinnatis, pinnis intergris (nightshade with a smooth annual stem with pinnate leaves, and leaflets entire). In each case, he gives for reference four or five further descriptive Latin phrases, some similar, some not, that other botanists have used for each plant. So what on earth do you call them? Sixteen years later, Linnaeus had found the answer. Dr Knapp takes down another book: it is Species Plantarum, his massive 1753 catalogue of all known plants. (It is his personal copy, covered in his tiny, precise scrawl. I find it enthralling.)

She finds the solanums once again, and the tomato, and the potato. There are the Latin descriptive phrases once more (slightly altered now). But there, on the margin of the page, next to each one, is also a single word in italics. Linnaeus called these his "trivial names". It was a piece of shorthand for quick and easy reference, and it changed the world. Next to the phrase for tomato, there is the single word lycopersicum (it means "wolf peach"). And next to the phrase for potato there is the word tuberosum (which means "tuber-like"). And in that moment, the scientific name for the tomato became Solanum lycopersicum, and the name for the potato became Solanum tuberosum, and they have remained so to this day.

They could be easily remembered. Compared to the long phrases that had gone before, they were almost catchy. But they were still precise. Linnaeus had had the crucial insight that names could be scientifically accurate without lengthy description ; they merely needed to designate their subject.

The botanical world saw the point and adopted the system virtually immediately. Five years later, in another book, Linnaeus applied it to creatures. Dr Knapp gets that one down from the shelf too (it is the much-expanded tenth edition of Systema Naturae), and there, at the beginning, is the entry for man, Homo, and at the side, for the first time in 1758, the adjective we are all too familiar with now: sapiens, meaning wise. ("I wonder if he was being ironic," Sandy wryly muses.) From Homo sapiens down, every organism was from then on given a Linnaean-style name.

The great namer himself was one of those lucky scientists whose achievements are fully recognised in their own lifetimes. He was fted across Europe by figures such as Rousseau and Goethe, and in 1761 he was ennobled by the King of Sweden, becoming Carl von Linne.

To his particular gratification, he was even commemorated in the name of a plant. It is the twinflower, Linnaea borealis, a small, delicate, pale-pink double bell, found in northern Britain, but particularly a plant of Lapland. Linnaeus adopted it as his symbol - he is seen holding one in his portrait on the Linnean Society's staircase - but he did not, of course, name it personally. Naming a species after yourself is considered extremely bad form, even today. He persuaded a leading Dutch botanist who had been one of his teachers, Jan Frederik Gronovius, to name it for him.

The species that Linnaeus did name himself are followed, when their scientific names are written out in full, with the letter "L". (Raven: Corvus corax L.) There are close on 10,000 of them, more than 7,000 of which belong to plants (the first full catalogue of the plant names is being published today, by Knapp's Natural History Museum colleague Dr Charlie Jarvis, after 25 years' work).

So one can hardly say that Linnaeus is forgotten. But perhaps it is the case that his naming system is now so much a part of our intellectual currency that we take it for granted, and forget what an advance it was. I would compare it to another huge intellectual leap forward by Western society: the adoption of Arabic numerals, which made complex mathematics and technology possible.

Carl Linnaeus's binomial nomenclature enabled humankind to order and comprehend the wonderful variety of life on Earth, and now, when we are destroying so much of that life, we should celebrate him more than ever.