Two Words for Every Living Thing: How Carl Linnaeus Named Us Homo sapiens

Carl Linnaeus (1707–1778) named plants and animals with a simple two-part system: the first word names the group a species belongs to, called the genus, and the second word picks out the particular species inside that group, as in Homo sapiens for modern humans. He did not invent every piece of this idea, but he was the one who made it a consistent rule, beginning with his book Species Plantarum in 1753, and for this reason he is known as the father of modern taxonomy. He also arranged living things into a ladder of ranks, from kingdoms down to species, which biologists still use in a modified form today.

A boy who calmed down with a flower

Linnaeus was born on 23 May 1707 in the village of Råshult in Småland, in southern Sweden, the first child of a Lutheran minister who was also a keen amateur gardener. His father taught him Latin as a small child, a gift that would matter enormously later on. As a toddler, it is said, whenever Carl was upset he was handed a flower and calmed down at once, and soon he had his own little patch of garden.

There is a nice language story in his surname too. Swedish families of his class had often used patronymics, names built from a father's first name, rather than fixed surnames. When his father entered university he needed a family name and chose the Latin-sounding Linnæus, after a giant linden tree, lind in Swedish, that grew on the family land. So the man who would name half of nature was himself named after a tree.

School did not go smoothly. Carl spent more time hunting for plants in the countryside than studying, and his teachers told his father that the boy would never become a scholar; at one point his father even thought about apprenticing him to a shoemaker. A local doctor, Johan Rothman, saw something different. He took Carl into his home, taught him botany and physiology and suggested a future in medicine. It is a reminder that one adult who believes in a student can change a life.

Uppsala, Lapland and a fake monster

Linnaeus studied first at Lund and then at Uppsala University. At Uppsala his paper on how plants reproduce caught the attention of a senior professor, and in 1730, while still a young student, he was asked to give lectures himself; audiences of about three hundred people came to hear him. That winter he began to doubt the plant classification system he had been taught and decided to build his own, sorting flowering plants by the number of their male and female parts.

In 1732 he set out on a six-month journey of more than 2,000 kilometres through Lapland, in the far north, travelling on foot and on horseback. He collected plants, birds and rocks and described about a hundred plants that had not been identified before, which became the basis of his book Flora Lapponica. He was also curious about the reindeer-herding Sami people and their way of life.

In 1735 he travelled to the Dutch Republic to earn a medical degree. On the way, in Hamburg, the mayor proudly showed him a stuffed seven-headed hydra. Linnaeus quickly saw that it was a fake made from weasel jaws and paws and snake skins, said so publicly, ruined the mayor's hopes of selling it for a fortune and had to leave the city in a hurry. In the Netherlands he finished his doctorate within two weeks, and a Dutch scientist was so impressed by one of his manuscripts that he helped pay to print it as Systema Naturae in 1735.

The problem with long names

To see why Linnaeus mattered, you have to know what names looked like before him. Scientific names were often short Latin descriptions rather than labels. One common plant was called, in effect, plantain with hairy oval leaves, a cylindrical spike and a rounded stalk, all written in Latin. Every time someone discovered a similar plant, the description had to grow longer to tell them apart, so names became unwieldy and hard to remember.

Earlier botanists, especially Caspar Bauhin, had already trimmed some names down, often to two words. Linnaeus's move in Species Plantarum was to always add a single extra word after the genus name. His key insight was that a name did not need to describe the plant at all; it only needed to be a unique label. Names could even honour people, so a plant group was named Tradescantia after the English gardener John Tradescant. These short names were much easier to remember and use, and in time they replaced the long ones.

How to read a scientific name

Think of a binomial name like a person's family name and first name, only in reverse order. In Homo sapiens, Homo is the genus, a bit like a family name, and sapiens identifies the species within it. Both words are Latin: homo means human or man, and sapiens means wise. The genus is always written with a capital letter, the second word with a small letter, and the whole name in italics. Some of these names have slipped into everyday speech, such as Tyrannosaurus rex, Aloe vera and E. coli.

The big advantage is that the same name works in every country. Common names change from language to language, but a Japanese, Brazilian and Swedish scientist all know exactly which plant or animal is meant by its binomial name. For a language learner that is a pleasant surprise: there is a small corner of vocabulary that is the same all over the world. Even the letter L. after many plant names is a tiny tribute to him, because it is the standard abbreviation showing that Linnaeus first named that species.

Putting humans among the animals

Linnaeus also grouped living things into nested levels: kingdoms divided into classes, classes into orders, orders into genera and genera into species. He placed humans inside the animal kingdom next to monkeys and apes, which shocked many readers who believed humans had been created separately. In the tenth edition of Systema Naturae in 1758, he introduced the terms Mammalia and Primates and gave humans the full name Homo sapiens. That edition is now the official starting point for naming animals, just as Species Plantarum is for plants. Linnaeus is also behind the popular use of the Mars and Venus symbols for male and female, which became standard sex symbols.

Professor, teacher and nobleman

Back in Sweden, Linnaeus became a professor at Uppsala and later rector of the university. Perhaps his most important work there was teaching. He encouraged students to think for themselves and not to trust anybody blindly, not even him, and his summer Saturday excursions around Uppsala were even more popular than his lectures. He called his seventeen most devoted students his apostles, and they travelled across the world collecting plants, animals and minerals and sorting them according to his system.

In 1761 he was ennobled and took the name Carl von Linné; his coat of arms featured the twinflower, a small plant named Linnaea borealis in his honour. His last years were difficult. A series of strokes from 1774 onward partly paralysed him and damaged his memory, and he died on 10 January 1778 at his country home of Hammarby.

A legacy of order, with a shadow

By the time of his death he was one of the most celebrated scientists in Europe, and writers admired him widely. Rousseau said he knew no greater man on earth, and the Swedish author August Strindberg called him a poet who happened to become a naturalist. He is also counted among the founders of modern ecology.

His legacy is not entirely comfortable, though. In Systema Naturae he divided humans into four varieties linked to continents and described mainly by skin colour, later adding stereotyped traits of character. In the twenty-first century this has been strongly criticised. Some scholars see him as a forerunner of scientific racism, while others argue that his scheme was stereotyped but did not rank one group above another. It is fair to remember both sides: a system of naming that brought order to biology, and categories about people that later generations rightly questioned.

Learn with Linnaeus: English phrases

Phrase	Meaning	Example
to put a name to	to identify something exactly	Linnaeus could put a name to almost any plant.
to branch out	to start doing new things	He branched out from plants to animals.
to be in your element	to feel comfortable and happy	On field trips he was in his element.
to sort the wheat from the chaff	to separate the useful from the useless	His system sorted the wheat from the chaff.
to have green fingers	to be good at growing plants	His father had green fingers.

Try this: Write three English sentences about how you organise your vocabulary notes, using "to branch out" and "to put a name to".