Carl Linnaeus (1707–1778), a Swedish physician, naturalist, and scientist, worked in the field of systematic biology. In the 18th century, he developed and applied the binomial nomenclature system, which is used to classify living organisms. He is best known for his work Systema Naturae, in which he divided plant, animal, and mineral species into hierarchical categories. His work Species Plantarum is considered the starting point of modern plant taxonomy.

Youth and Education

Carl Linnaeus was born on May 23, 1707, in the village of Råshult in the Småland region of Sweden. His father, Nils Ingemarsson Linnaeus, was a Lutheran priest with a strong interest in gardening. His mother, Christina Brodersonia, also came from a clerical family. The family moved to Stenbrohult a year after Linnaeus was born. He spent his childhood among various vegetables, fruits, and ornamental plants in the garden next to his father's church—a setting that nurtured his interest in plants.

He completed his primary and secondary education in Växjö. In 1727, he enrolled at Lund University to study medicine. A year later, in 1728, he transferred to Uppsala University, one of Sweden's leading institutions of higher learning. At Uppsala, medical studies included botany, and Linnaeus became particularly interested in plant sexual reproduction, leading to his early ideas on floral classification. In 1730, while still a student, he was temporarily assigned to lecture on botany and began teaching students about medicinal plants in the Uppsala Botanical Garden.

In 1732, with support from the Uppsala Scientific Society, he undertook a research expedition to the Lapland region in northern Sweden. In 1734, he explored the mining areas of Dalarna (Dalecarlia). By this time, his scientific interests extended beyond medicine. In 1735, he left Sweden with his manuscripts and traveled to the Netherlands, where he earned his doctorate in medicine at the University of Harderwijk. His dissertation was on malaria. He continued his studies at Leiden University and established connections by working with scientists in his field.

Career and Scientific Activities

After earning his doctorate in the Netherlands in 1735, Carl Linnaeus began publishing scientific works. He worked in botanical gardens in Leiden, Amsterdam, and Hartekamp, met scientists, and published many books. He spent two years at George Clifford’s private botanical garden in Amsterdam, where he compiled plant catalogues and published works such as Hortus Cliffortianus.

In 1736, he visited England and connected with botanists. Returning to Sweden in 1738, he began practicing medicine in Stockholm and lectured at the Mining College. In 1739, he was involved in the founding of the Royal Swedish Academy of Sciences and became its first head. That same year, he married Sara Elisabeth Moraea.

In 1741, he was appointed professor at Uppsala University. He reorganized the university’s botanical garden according to his classification system, enriched its herbarium, and provided both theoretical and practical training in botany. During his tenure, he undertook numerous domestic scientific expeditions, documenting plant life, public health, geography, mineral resources, and natural features of various regions.

In 1753, he published Species Plantarum, considered the starting point of modern plant nomenclature. In its 10th edition, published in 1758, Systema Naturae extended the binomial system to animals, laying the groundwork for a new standard in taxonomy. His system aimed to categorize organisms into five hierarchical ranks: kingdom, class, order, genus, and species. In plant classification, he proposed an artificial system based on the number and structure of floral organs. In later years, he attempted to establish a more natural system and expressed these views in the 1764 edition of Genera Plantarum.

Research Expeditions

Linnaeus’ first research expedition took place in 1732 with the support of the Royal Swedish Academy of Sciences, covering northern Sweden and Finland (Lapland). Between May and October, he observed the region’s flora, local communities, geography, and mineral resources. Based on this journey, he wrote Flora Lapponica, published in Amsterdam in 1737.

In 1733, he conducted several expeditions in the Dalarna region, focusing on copper and sandstone mines in Falun. These journeys led to manuscripts such as Iter ad Fodinas (Journey to the Mines), Diaeta naturalis (Natural Diet), and Systema lapidorum (Classification of Stones). He studied not only plants but also mineral resources during these trips.

In 1741, he was sent to the Öland and Gotland islands to assess their economic potential. He also visited Västergötland in 1746 and Skåne in 1749. During these expeditions, he systematically recorded observations, collecting floristic, geographic, socio-economic, and natural resource data.

Scientific Contributions and Classification System

Carl Linnaeus's most significant contribution was the development of an artificial classification system and the introduction of binomial nomenclature for organizing living organisms. This system simplified the classification and naming of species and became foundational in modern taxonomy. Linnaeus classified organisms in five ranks: kingdom (regnum), class (classis), order (ordo), genus (genus), and species (species), with further subdivisions (such as family, subspecies) added later.

Binomial Nomenclature

Linnaeus proposed that each species should be named using two Latin words: the genus followed by the specific epithet. This replaced the previously long and inconsistent Latin descriptions. For example, the wild rose was designated as Rosa canina. He systematically applied this method in Species Plantarum (1753), and it became standard for animals with the 10th edition of Systema Naturae (1758).

Sexual System (Systema Sexuale)

To classify plants, Linnaeus developed a system based on the number of sexual organs—stamens and pistils—in flowers. In this artificial system, flowering plants were grouped into classes like “Triandria” (three stamens) or “Hexandria” (six stamens). In total, he defined 24 classes: 23 for flowering plants and one (Cryptogamia) for non-flowering plants. He clarified that the system was artificial and designed to facilitate identification.

Natural System Initiative

Linnaeus also attempted to develop a classification system based on natural affinities among plants. In the sixth edition of Genera Plantarum (1764), he introduced a more natural system with 58 orders. Some of the order names, such as Gramineae, Palmae, and Orchidaceae, are now used as family names in modern taxonomy.

Later Years and Death

In 1761, the King of Sweden granted Linnaeus nobility, after which he adopted the name Carl von Linné. He continued his professorship at Uppsala University but began delegating lectures to his son, Carl Linnaeus the Younger, from 1763 onward. He spent winters in Uppsala and summers at his country home in Hammarby, both of which now serve as museums. His health declined after 1772, and after at least two years of illness, he died on January 10, 1778, in Uppsala at the age of 70. He was buried in Uppsala Cathedral. In 1783, his manuscripts, books, plant specimens, and other natural history collections were sold to English naturalist James Edward Smith and later acquired by the Linnean Society in London.