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A Brief History of the Science of Naming Things

 
 

I'd like to tell you about a certain animal that you might find interesting. It is scientifically known as Mus musculus and it’s a rather small, furry and territorial mammal. It grows up to around 10 cm, its fur color varies and it is one of the most abundant species of the genus Mus. It’s a very peculiar species. It’s a great swimmer and climber and it can jump up to a foot in the air. It can control the blood flow to its furless tail, raising it’s surface heat by 10 degrees Celsius, in order to lose body heat if it needs to. It  communicates by using pheromones, secreted by a specific gland or in tears and urine, which is convenient because it continually leaves behind tiny droplets of urine as it walks around, along with around 80 droppings a day. It’s eyesight is not great, it sees fewer colors than we do, but it mostly senses its surroundings with its whiskers.

I’m sure you’ve guessed the common name of this Mus musculus - it’s the house mouse. Mus musculus is its binomial name (from Greek - binomial means ‘of two parts’). Every known species, extinct or extent, of animal, plant, bacteria and even minerals have binomial names. These names help us arrange the mind-boggling amount of species into one universal and standard system. The scientific field that deals with this nomenclature is called Taxonomy - the name is derived from Greek and it means ‘arrangement method’.

It is an old field of science, dating perhaps back to 3,000 b.c., in one form or another. Back then, they believed that there were a few hundreds of species in existence and that it is possible to classify them all. Today we know that there are many more than that. In fact, the latest estimations put the number of existing species at around 8.7 million, give or take 1.3 million, while excluding bacteria and archaea. Out of that estimated number, we only know about 15% of the species.

For every animal or plant you know there are plenty of variants, usually many more than we can guess. Take roses (genus: Rosa) for example. How many different types of roses do you think there are? My first guess was ‘about 20’. Well, it turns out that there are around 150 species of roses, each has its own unique characteristics. This large number makes it important that we are able to identify and distinguish the different types.  

Being able to tell apart the different species lets us, for example, test only species with properties that are important to us. For example, many marine sponges produce materials that have medicinal properties. If we could not differentiate between the species, our methods of testing for these materials would be much less efficient.

As I’ve mentioned earlier, taxonomy has taken many forms throughout history. At first, it was used differently in many places, but at some point, it was unified to a single system that is constantly reshaped and improved by the experience and needs of those who use it. Even today taxonomy is facing a new front that may change the way we classify species. Reviewing the origins and evolution of Taxonomy gives us a good overview of the many problems it faced and solved, and how useful and dynamic it is today.

The earliest forms of taxonomy took place a very long time ago. In ancient China, Emperor Shennong wrote a pharmacopeia, a classification of plants based on their medicinal properties, at around 3000 BC. In Egypt, there are wall paintings of medicinal plants and their names from around 1500 BC. One of the famous early taxonomists was Aristotle (384-320 BC). He tried to classify all living things into groups, but there was quite a flaw in his system - inconsistency. He grouped species together without following any plan and so his system eventually did not make much sense. His work was not doomed to be forgotten, though, as some of the names he coined are still in use today, such as crustacea - a subphylum that consists of lobsters, crabs and Shrimp.

Theophrastus, who was a friend of Aristotle, also tried to create a system of his own. He is remembered, among other things, for coining the term ‘botanic’ (plant, from Greek). His system also had flaws and thus eventually faded away. One system from that time period that held for a surprisingly long while was one by Dioscorides, named ‘De Materia Medica’ - ‘on medical material’ (~50-70AD). This book was used in medicine until the 16th century, which is a fact that points at the slow pace of progress of those times. ‘De Materia Medica’ was a pharmacopeia that contained around 600 species, mostly plants, based on their medical properties.

During the age of renaissance, the pace was picked up as the knowledge of living things was expanding quicker than ever. There was much exploring and so new species were constantly being discovered. Another big development of the time was the optic lens, which made more details available to observers. This must have been a very interesting period of time. With many new species and new tools to observe them, scientists were finding the old methods of classifications somewhat lacking. This has brought along a generous amount of new classification systems. But more does not always mean better.

Many of the systems that were used at 16-17th centuries were used nationally. That means that scientists from different countries used different systems, a practice that has led to much confusion. That’s without even mentioning that some systems were not even nationally used, but personally. Each system then was based on a different classification method - some classified by areas in which the plant or animal is found, some worked by visual appearance and some were based on what properties the classifiers believed were attributed to the species.

The names given to each organism were different in every system. Names were used to express either known locations or features of the species, and sometimes even both. When more species were discovered, new words were added to their name to allow for better separation of different species. This has sometimes resulted in species with names of up to 60 words. To add to the confusion, remember that each system was based on a different language. Some books, like those written by the Bauhin brothers, included synonyms, which is a great effort, but I still can’t see how this could have resulted in anything other than general confusion.

Lucky for us, along came the father of taxonomy, Carl Linnaeus (1707-1778). Linnaeus was a Swedish scientist whose work is still as important today as it was back in his time. He started his career as a botanist, traveled across Europe, earned a medical degree and then went back to Sweden to teach botany and zoology among other subjects. It is said that, as a religious man, his purpose in classifying organisms was a form of appreciation of God’s work. Ironically, it turned out to be a major step in the evolution of science.

Linnaeus noticed the flaws that were prevalent in classification systems in his time and he sought to fix them. He formed a system that addressed these problems and could thus become a standard. To get over the language barrier, his system was established in Latin, a language that science has a deep and established connection with. To create consistency in the system, he proposed to uniformly classify plants according to their reproductive organs. To make sure that his system was easy to use, he left behind the phrase names that were common and began using the binomial (two-name) system - each organism would be called by his genus and species name, the two lowest ranks of taxonomy (for a short explanation of taxonomic hierarchy, check out the additional notes).

Linnaeus’ earliest version of the system was first proposed in 1736, and it has gone through many alterations until 1750, and even more in the years to come. Linnaeus’ idea of classifying plants by their reproductive organs was, at first, scoffed at and it was not immediately a big success. Soon, though, many would come to see the benefits, consistency, and practicality of it and slowly it would catch on. Even after the popularization of this system, there were still many changes to come.

In Linnaeus’s time, the idea of evolution has not yet surfaced. Still, the systematic method of classification has, in a way, pointed in that direction. For example, a similarity between man and ape was already noticed and thus the two species were classified relatively close together. It is said that Linnaeus’ writings had inspired many naturalists and scientists, including Charles Darwin, the father of evolution. During the 19th and 20th-century scientists have begun to use evolutionary trees. By then, classification was not based solely on morphology, but on anatomy and biochemistry as well. This means that species that are grouped together are more closely related and thus likely to share traits on a genetic level.

As I mentioned before, the beauty of this system is that it is always improved by new requirements and experience. That does not mean that it moves quickly - it took until 1935 for the American and European systems to merge and become the International Code of Botanical Nomenclature. It does mean that even today essential changes are happening or are being considered.

Current technologies allow us to do things we never could before. Faster computing power allows us to process amazing amounts of data. A technique called Polymerase Chain Reaction (PCR) lets us amplify small amounts of DNA for research. Genetic sequencing methods are more reliable than ever. This all means that we can now compare DNA of different organisms in unprecedented efficiency and classify them by genetic relations, in a scientific field known as Cladistics. Some scientists oppose this method, as it contradicts some of the classifications that are in present use. Today, many forms of science rely on DNA analysis and it proves to be highly dependable. I believe that this form of classification has a good chance of becoming a main system of classification in the future.

Even though today’s taxonomy is not what it was in Linnaeus’ time, many scientists still believe that his contributions to the field are as important today as they were then. To this day, Linnaeus, who has given us the name Homo sapiens, has the honor of being the type specimen. The system he has given us has roots that go years and years before he came along and still evolves years after he passed. To me, this system exemplifies the virtues of learning from experience and always striving for improvement. These are lessons that scientists strive to apply in their work, and we should all try to involve in our daily lives.


Last week I wrote a riddle that gives a clue about the subject of this article, the answer to that riddle is in the Additional Notes, along with some more information about species named after famous people and other interesting facts.

The painting of Carl Linnaeus was painted by Per Krafft the Elder, and is taken from Wikimedia Commons.

 

Thank you very much for reading the article!

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