Carl Linnaeus (23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné ), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin; his name is rendered in Latin as Carolus Linnæus and, after his 1761 ennoblement, as Carolus a Linné.

Linnaeus was born in Råshult, the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his Systema Naturae in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, while publishing several volumes. He was one of the most acclaimed scientists in Europe at the time of his death.

Philosopher Jean-Jacques Rousseau sent him the message: “Tell him I know no greater man on earth.” Johann Wolfgang von Goethe wrote: “With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly.” Swedish author August Strindberg wrote: “Linnaeus was in reality a poet who happened to become a naturalist.” Linnaeus has been called Princeps botanicorum (Prince of Botanists) and "The Pliny of the North". He is also considered one of the founders of modern ecology.

In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains constitute the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself.

Early life

Childhood

Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus (Nils) Ingemarsson (who later adopted the family name Linnaeus) and Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus (who would eventually succeed their father as rector of Stenbrohult and write a manual on beekeeping), and Emerentia Linnæa. His father taught him Latin as a small child.

One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, and the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius.

A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curate's house.

Even in his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which immediately calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth where he could grow plants.

Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson. When Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree (or lime tree), lind in Swedish, that grew on the family homestead. This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name. The son also always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus.

Early education

Linnaeus's father began teaching him basic Latin, religion, and geography at an early age. When Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked Johan Telander, a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them".

Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus rarely studied, often going to the countryside to look for plants. At some point, his father went to visit him and, after hearing critical assessments by his preceptors, he decided to put the youth as an apprentice to some honest cobbler. He reached the last year of the Lower School when he was fifteen, which was taught by the headmaster, Daniel Lannerus, who was interested in botany. Lannerus noticed Linnaeus's interest in botany and gave him the run of his garden.

He also introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan (a gymnasium) in Växjö. Also a botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature. He remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii's Chloros Gothica and Rudbeckii's Hortus Upsaliensis".

Linnaeus entered the Växjö Katedralskola in 1724, where he studied mainly Greek, Hebrew, theology and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing; to his dismay, most said that the boy would never become a scholar. Rothman believed otherwise, suggesting Linnaeus could have a future in medicine. The doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer.

University studies

Lund

Rothman showed Linnaeus that botany was a serious subject. He taught Linnaeus to classify plants according to Tournefort's system. Linnaeus was also taught about the sexual reproduction of plants, according to Sébastien Vaillant. In 1727, Linnaeus, age 21, enrolled in Lund University in Skåne. He was registered as Carolus Linnæus, the Latin form of his full name, which he also used later for his Latin publications.

Professor Kilian Stobæus, natural scientist, physician and historian, offered Linnaeus tutoring and lodging, as well as the use of his library, which included many books about botany. He also gave the student free admission to his lectures. In his spare time, Linnaeus explored the flora of Skåne, together with students sharing the same interests.

Uppsala

In August 1728, Linnaeus decided to attend Uppsala University on the advice of Rothman, who believed it would be a better choice if Linnaeus wanted to study both medicine and botany. Rothman based this recommendation on the two professors who taught at the medical faculty at Uppsala: Olof Rudbeck the Younger and Lars Roberg. Although Rudbeck and Roberg had undoubtedly been good professors, by then they were older and not so interested in teaching. Rudbeck no longer gave public lectures, and had others stand in for him. The botany, zoology, pharmacology and anatomy lectures were not in their best state. In Uppsala, Linnaeus met a new benefactor, Olof Celsius, who was a professor of theology and an amateur botanist. He received Linnaeus into his home and allowed him use of his library, which was one of the richest botanical libraries in Sweden.

In 1729, Linnaeus wrote a thesis, Praeludia Sponsaliorum Plantarum on plant sexual reproduction. This attracted the attention of Rudbeck; in May 1730, he selected Linnaeus to give lectures at the University although the young man was only a second-year student. His lectures were popular, and Linnaeus often addressed an audience of 300 people. In June, Linnaeus moved from Celsius's house to Rudbeck's to become the tutor of the three youngest of his 24 children. His friendship with Celsius did not wane and they continued their botanical expeditions. Over that winter, Linnaeus began to doubt Tournefort's system of classification and decided to create one of his own. His plan was to divide the plants by the number of stamens and pistils. He began writing several books, which would later result in, for example, Genera Plantarum and Critica Botanica. He also produced a book on the plants grown in the Uppsala Botanical Garden, Adonis Uplandicus.

Rudbeck's former assistant, Nils Rosén, returned to the University in March 1731 with a degree in medicine. Rosén started giving anatomy lectures and tried to take over Linnaeus's botany lectures, but Rudbeck prevented that. Until December, Rosén gave Linnaeus private tutoring in medicine. In December, Linnaeus had a "disagreement" with Rudbeck's wife and had to move out of his mentor's house; his relationship with Rudbeck did not appear to suffer. That Christmas, Linnaeus returned home to Stenbrohult to visit his parents for the first time in about three years. His mother had disapproved of his failing to become a priest, but she was pleased to learn he was teaching at the University.

Return to Sweden

When Linnaeus returned to Sweden on 28 June 1738, he went to Falun, where he entered into an engagement to Sara Elisabeth Moræa. Three months later, he moved to Stockholm to find employment as a physician, and thus to make it possible to support a family. Once again, Linnaeus found a patron; he became acquainted with Count Carl Gustav Tessin, who helped him get work as a physician at the Admiralty. During this time in Stockholm, Linnaeus helped found the Royal Swedish Academy of Science; he became the first Praeses of the academy by drawing of lots.

Because his finances had improved and were now sufficient to support a family, he received permission to marry his fiancée, Sara Elisabeth Moræa. Their wedding was held 26 June 1739. Seventeen months later, Sara gave birth to their first son, Carl. Two years later, a daughter, Elisabeth Christina, was born, and the subsequent year Sara gave birth to Sara Magdalena, who died when 15 days old. Sara and Linnaeus would later have four other children: Lovisa, Sara Christina , Johannes and Sophia.

In May 1741, Linnaeus was appointed Professor of Medicine at Uppsala University, first with responsibility for medicine-related matters. Soon, he changed place with the other Professor of Medicine, Nils Rosén, and thus was responsible for the Botanical Garden (which he would thoroughly reconstruct and expand), botany and natural history, instead. In October that same year, his wife and nine-month-old son followed him to live in Uppsala.

Öland and Gotland

Ten days after he was appointed Professor, he undertook an expedition to the island provinces of Öland and Gotland with six students from the university to look for plants useful in medicine. First, they travelled to Öland and stayed there until 21 June, when they sailed to Visby in Gotland. Linnaeus and the students stayed on Gotland for about a month, and then returned to Uppsala. During this expedition, they found 100 previously unrecorded plants. The observations from the expedition were later published in Öländska och Gothländska Resa, written in Swedish. Like Flora Lapponica, it contained both zoological and botanical observations, as well as observations concerning the culture in Öland and Gotland.

During the summer of 1745, Linnaeus published two more books: Flora Suecica and Fauna Suecica. Flora Suecica was a strictly botanical book, while Fauna Suecica was zoological. Anders Celsius had created the temperature scale named after him in 1742. Celsius's scale was inverted compared to today, the boiling point at 0 °C and freezing point at 100 °C. In 1745, Linnaeus inverted the scale to its present standard.

Västergötland

In the summer of 1746, Linnaeus was once again commissioned by the Government to carry out an expedition, this time to the Swedish province of Västergötland. He set out from Uppsala on 12 June and returned on 11 August. On the expedition his primary companion was Erik Gustaf Lidbeck, a student who had accompanied him on his previous journey. Linnaeus described his findings from the expedition in the book Wästgöta-Resa, published the next year. After he returned from the journey, the Government decided Linnaeus should take on another expedition to the southernmost province Scania. This journey was postponed, as Linnaeus felt too busy.

In 1747, Linnaeus was given the title archiater, or chief physician, by the Swedish king Adolf Frederick—a mark of great respect. The same year he was elected member of the Academy of Sciences in Berlin.

Scania

In the spring of 1749, Linnaeus could finally journey to Scania, again commissioned by the Government. With him he brought his student, Olof Söderberg. On the way to Scania, he made his last visit to his brothers and sisters in Stenbrohult since his father had died the previous year. The expedition was similar to the previous journeys in most aspects, but this time he was also ordered to find the best place to grow walnut and Swedish whitebeam trees; these trees were used by the military to make rifles. While there, they also visited the Ramlösa mineral spa, where he remarked on the quality of its ferruginous water. The journey was successful, and Linnaeus's observations were published the next year in Skånska Resa.

Rector of Uppsala University

In 1750, Linnaeus became rector of Uppsala University, starting a period where natural sciences were esteemed. Perhaps the most important contribution he made during his time at Uppsala was to teach; many of his students travelled to various places in the world to collect botanical samples. Linnaeus called the best of these students his "apostles". His lectures were normally very popular and were often held in the Botanical Garden. He tried to teach the students to think for themselves and not trust anybody, not even him. Even more popular than the lectures were the botanical excursions made every Saturday during summer, where Linnaeus and his students explored the flora and fauna in the vicinity of Uppsala.

Philosophia Botanica

Linnaeus published Philosophia Botanica in 1751. The book contained a complete survey of the taxonomy system he had been using in his earlier works. It also contained information of how to keep a journal on travels and how to maintain a botanical garden.

Final years

Linnaeus was relieved of his duties in the Royal Swedish Academy of Science in 1763, but continued his work there as usual for more than ten years after. In 1769 he was elected to the American Philosophical Society for his work. He stepped down as rector at Uppsala University in December 1772, mostly due to his declining health.

Linnaeus's last years were troubled by illness. He had had a disease called the Uppsala fever in 1764, but survived due to the care of Rosén. He developed sciatica in 1773, and the next year, he had a stroke which partially paralysed him. He had a second stroke in 1776, losing the use of his right side and leaving him bereft of his memory; while still able to admire his own writings, he could not recognise himself as their author.

In December 1777, he had another stroke which greatly weakened him, and eventually led to his death on 10 January 1778 in Hammarby. Despite his desire to be buried in Hammarby, he was buried in Uppsala Cathedral on 22 January.

His library and collections were left to his widow Sara and their children. Joseph Banks, an eminent botanist, wished to purchase the collection, but his son Carl refused the offer and instead moved the collection to Uppsala. In 1783 Carl died and Sara inherited the collection, having outlived both her husband and son. She tried to sell it to Banks, but he was no longer interested; instead an acquaintance of his agreed to buy the collection. The acquaintance was a 24-year-old medical student, James Edward Smith, who bought the whole collection: 14,000 plants, 3,198 insects, 1,564 shells, about 3,000 letters and 1,600 books. Smith founded the Linnean Society of London five years later.

The von Linné name ended with his son Carl, who never married. His other son, Johannes, had died aged 3. There are over two hundred descendants of Linnaeus through two of his daughters.

Apostles

During Linnaeus's time as Professor and Rector of Uppsala University, he taught many devoted students, 17 of whom he called "apostles". They were the most promising, most committed students, and all of them made botanical expeditions to various places in the world, often with his help. The amount of this help varied; sometimes he used his influence as Rector to grant his apostles a scholarship or a place on an expedition. To most of the apostles he gave instructions of what to look for on their journeys. Abroad, the apostles collected and organised new plants, animals and minerals according to Linnaeus's system. Most of them also gave some of their collection to Linnaeus when their journey was finished. Thanks to these students, the Linnaean system of taxonomy spread through the world without Linnaeus ever having to travel outside Sweden after his return from Holland. The British botanist William T. Stearn notes, without Linnaeus's new system, it would not have been possible for the apostles to collect and organise so many new specimens. Many of the apostles died during their expeditions.

Early expeditions

Christopher Tärnström, the first apostle and a 43-year-old pastor with a wife and children, made his journey in 1746. He boarded a Swedish East India Company ship headed for China. Tärnström never reached his destination, dying of a tropical fever on Côn Sơn Island the same year. Tärnström's widow blamed Linnaeus for making her children fatherless, causing Linnaeus to prefer sending out younger, unmarried students after Tärnström. Six other apostles later died on their expeditions, including Pehr Forsskål and Pehr Löfling. Two years after Tärnström's expedition, Finnish-born Pehr Kalm set out as the second apostle to North America. There he spent two-and-a-half years studying the flora and fauna of Pennsylvania, New York, New Jersey and Canada. Linnaeus was overjoyed when Kalm returned, bringing back with him many pressed flowers and seeds. At least 90 of the 700 North American species described in Species Plantarum had been brought back by Kalm.

Cook expeditions and Japan

Daniel Solander was living in Linnaeus's house during his time as a student in Uppsala. Linnaeus was very fond of him, promising Solander his eldest daughter's hand in marriage. On Linnaeus's recommendation, Solander travelled to England in 1760, where he met the English botanist Joseph Banks. With Banks, Solander joined James Cook on his expedition to Oceania on the Endeavour in 1768–71. Solander was not the only apostle to journey with James Cook; Anders Sparrman followed on the Resolution in 1772–75 bound for, among other places, Oceania and South America. Sparrman made many other expeditions, one of them to South Africa.

Perhaps the most famous and successful apostle was Carl Peter Thunberg, who embarked on a nine-year expedition in 1770. He stayed in South Africa for three years, then travelled to Japan. All foreigners in Japan were forced to stay on the island of Dejima outside Nagasaki, so it was thus hard for Thunberg to study the flora. He did, however, manage to persuade some of the translators to bring him different plants, and he also found plants in the gardens of Dejima. He returned to Sweden in 1779, one year after Linnaeus's death.

System of taxonomy

The establishment of universally accepted conventions for the naming of organisms was Linnaeus's main contribution to taxonomy—his work marks the starting point of consistent use of binomial nomenclature. During the 18th century expansion of natural history knowledge, Linnaeus also developed what became known as the Linnaean taxonomy; the system of scientific classification now widely used in the biological sciences. A previous zoologist Rumphius (1627–1702) had more or less approximated the Linnaean system and his material contributed to the later development of the binomial scientific classification by Linnaeus.

The Linnaean system classified nature within a nested hierarchy, starting with three kingdoms. Kingdoms were divided into classes and they, in turn, into orders, and thence into genera (singular: genus), which were divided into species (singular: species). Below the rank of species he sometimes recognised taxa of a lower (unnamed) rank; these have since acquired standardised names such as variety in botany and subspecies in zoology. Modern taxonomy includes a rank of family between order and genus and a rank of phylum between kingdom and class that were not present in Linnaeus's original system.

Linnaeus's groupings were based upon shared physical characteristics, and not based upon differences. Of his higher groupings, only those for animals are still in use, and the groupings themselves have been significantly changed since their conception, as have the principles behind them. Nevertheless, Linnaeus is credited with establishing the idea of a hierarchical structure of classification which is based upon observable characteristics and intended to reflect natural relationships. While the underlying details concerning what are considered to be scientifically valid "observable characteristics" have changed with expanding knowledge (for example, DNA sequencing, unavailable in Linnaeus's time, has proven to be a tool of considerable utility for classifying living organisms and establishing their evolutionary relationships), the fundamental principle remains sound.

Human taxonomy

Linnaeus's system of taxonomy was especially noted as the first to include humans (Homo) taxonomically grouped with apes (Simia), under the header of Anthropomorpha. German biologist Ernst Haeckel speaking in 1907 noted this as the "most important sign of Linnaeus's genius".

Linnaeus classified humans among the primates beginning with the first edition of Systema Naturae. During his time at Hartekamp, he had the opportunity to examine several monkeys and noted similarities between them and man. He pointed out both species basically have the same anatomy; except for speech, he found no other differences. Thus he placed man and monkeys under the same category, Anthropomorpha, meaning “manlike.” This classification received criticism from other biologists such as Johan Gottschalk Wallerius, Jacob Theodor Klein and Johann Georg Gmelin on the ground that it is illogical to describe man as human-like. In a letter to Gmelin from 1747, Linnaeus replied:

It does not please [you] that I've placed Man among the Anthropomorpha, perhaps because of the term 'with human form', but man learns to know himself. Let's not quibble over words. It will be the same to me whatever name we apply. But I seek from you and from the whole world a generic difference between man and simian that [follows] from the principles of Natural History. I absolutely know of none. If only someone might tell me a single one! If I would have called man a simian or vice versa, I would have brought together all the theologians against me. Perhaps I ought to have by virtue of the law of the discipline.