May 22 marked the celebration of the International Day for Biological Diversity. What exactly does this term, or word Biodiversity mean? At the broadest level it refers to the variety among life forms. It describes not only the number but also the types and variety of living things. While there is a huge variety of sizes, structures and functions among living things, there are also sufficient similarities to permit their grouping together into orderly patterns.
This grouping is called classification. The science of classifying organisms is called taxonomy. When talking about taxonomy, the name that immediately comes to mind is that of Carl Linnaeus, who is most famous for creating a system of naming plants and animals—a system we still use today. But Carl Linnaeus was much more than just the ‘father of modern taxonomy’. He was a renowned botanist, physician and zoologist; a pioneer in the study of ecology, and one of the most influential scientists in history.
Carl Linnaeus was born on May 23, 1707, the eldest of five children, in a town called Råshult, in Sweden. His father Nils, was a minister and keen gardener. From the time Carl was very young, his father used to take him to the garden and teach him about plants. Carl observed his father in the garden, and was soon as excited and interested in plants. He began growing plants and by the age of five had his own little patch in the family’s large garden.
His father believed that the best thing he could offer his children was a solid education and, in addition to botany, he taught Carl Latin, as well as about religion at an early age. Nils also realized that his son was exceptionally bright, and engaged a private tutor for him; but the boy found the tutor very dull as compared to his own explorations in the garden and countryside. This aversion to formal education continued when he joined school at the age of ten, and Carl was an indifferent student. The teachers ignored his immense knowledge and interest in Botany because it was not considered a ‘proper’ subject, and as he was not interested in subjects like Hebrew, mathematics and theology, they advised that he was not bright enough to go to University. Only one of his teachers saw his potential and advised his father that the boy should apply for admission to medical school. He also coached him in anatomy and physiology.
At the age of 21 Carl enrolled in Lund University under the Latin form of his name Carolus Linnaeus. This was a common practice for students in Europe at that time. After a year he switched to Uppsala University as he was told that the medical and botany courses there were better. While he was there Carl wrote up some of his observations on reproduction in plants which were of such a high standard that he was offered a post of Botany lecturer at the University. In 1731 Carl began teaching botany, at the age of 23. He was a good teacher and his lectures were popular with students. As he continued his own botanical studies, Carl found that the way in which plants were classified was not satisfactory. He started jotting down ideas about how this could be improved. Linnaeus realized that he needed a cataloguing system that was easily expandable and easy to reorganize; for this he started using cards, thereby inventing index cards!
In 1732 Carl got funding for a botanical expedition to Lapland, in the far north of Sweden. For 6 months he travelled 2000 km across Lapland making notes on the native plants and birds. At this time it occurred to him that there could be another way of naming plants. He replaced some very lengthy plant names with logical, much shorter, two-part names which consisted of a genus and a species name. The genus describes a larger grouping of organisms with certain common characteristics, while the species name describes only one, unique particular organism grouped within that genus, or larger classification. The names were in Latin because at that time, Latin was the language of science. Highly educated people of the period could all read and write in Latin which enabled them to share scientific information, regardless of their native tongue.
Carl Linnaeus described his observations of plants along with the newly-coined names in a book called Flora Lapponica, including his new discoveries. He also realized that he could use his new system to name animals as well as plants.
In 1735, at the age of 28 Linnaeus was awarded a doctoral degree in medicine for his thesis on malaria and its causes from a University in the Netherlands. While he was there he showed his continuing work on the classification and renaming of plants to a Dutch botanist who was very excited by its potential to transform botany. He supported the publication of Carl’s work which was published in 1737 under the title Systema Naturae (System of Nature). The first edition had 12 outsize pages.
Over the years, Linnaeus continued to develop his ideas and add new species. In the tenth edition of Systema Naturae published in 1758, Linnaeus classified all the animal kingdom into genera and gave all the species two-part names. The twelfth edition had 2400 pages. During his career, Linnaeus named about 13,000 life forms and classified them into suitable categories such as mammals, birds, fish, primates, canines, etc.
Linnaeus returned to Sweden in 1738, becoming a physician in the nation’s capital city, Stockholm. He helped found the Royal Swedish Academy of Science and became its first president. In 1741, aged 34, Linnaeus returned to Uppsala University and became a full professor of medicine, taking control of botany, natural history and the university’s botanical garden. He also revived his childhood passion by taking his students on walking trips in the countryside searching for plants. In 1750, at the age of 43, Linnaeus was appointed as Uppsala University’s rector. Carolus Linnaeus was knighted by the King of Sweden in 1761 and took the nobleman’s name of Carl von Linné. He died at the age of 70, on 10 January 1778, after suffering a stroke.
Linnaeus was the first person to place humans in the primate family and to describe bats as mammals rather than birds. He did this with the same reasoning he used to categorize all life, which was based on similarities he identified between species. Human beings are also among the thousands of species that were given a name by Carl Linnaeus—Homo sapiens meaning ‘thinking man or wise man’!
Today as the world sees a steady decline in the numbers of species and a severe threat to global Biodiversity due to anthropogenic factors, one wonders if Carl Linnaeus would regret giving humans the title of ‘wise’!