The Linnaeus System of Taxonomy

Carl Linnaeus, for whom the Linneaeus system of taxonomy is named after.
Carl Linnaeus, for whom the Linneaeus system of taxonomy is named after.

The Linnaeus system of taxonomy is a set of rules for naming all living species. It was developed and put to great use by Carl Linnaeus, a Swedish zoologist and biologist, who introduced the use of a binomial type of nomenclature in the middle of the 18th century.

The Importance of The Linnaeus System

The great importance of the binomial nomenclature lies in the fact that it simplified the way in which scientists could interact with each other. No matter what was their native language, by embracing the Latin terminology for plants and animals, it was easier for everyone to know that, i.e., Canis is a dog (or that Canis lupus is the domestic dog).

Even though Linnaeus provided the hierarchy of species, genus, order, and class, his principal contribution is the system of keys used to identify animals and plants from his texts. He also set out to create a natural classification based on Aristotle’s system of essential attributes, but he did not succeed. The Aristotelian way of defining a form was by describing the genus (the general definition of the subject) and the differentia (a defining, distinctive characteristic). When the two parts are put together, created a name. However, as the species were being discovered, the particular feature of the plants and animals became too long, so Linnaeus came up with the genus name and one word from the differentia, i.e., Homo sapiens. This is how the binomial nomenclature was started.

How Does the Binominal Nomenclature Work?

As the name suggests, the Linnaean system for naming plants and animals takes two distinctive qualities in account to derive a name for a living being. The first one is the genus, and the second one is the species. So, for example, a Black Bear (American Black Bear) would be known as Ursus americanus. The genus is always capitalized, the species name following is not.

It is essential to mention that many living beings have two Linnaean designations; one is the original Linnaeus’ label and the other one it the currently accepted name in the scientific community.

Another interesting advancement within this taxonomy system is that, as the science progressed, new categories were added to the existing ones of species, genus, order, and class. The broadest of the newly added categories to the taxonomic hierarchy is domain.

The Domain System of Classification

The modern classification system groups organisms based on their structural differences in ribosomal RNA, instead of their physical characteristics, as the case was in the past. Carl Woese (an American biophysicist and microbiologist living during the second half of the 20th century) was the creator of this type of system, and it divides all living things under the archaea, bacteria, and eukarya domains.

The first one, the archaea domain, encompasses all organisms that are different from bacteria in their RNA and membrane structure, and are without a nucleus. These types of organisms are typically able to survive in even the most uninhabitable environments on the planet. The bacteria domain includes certain prokaryotic organisms that have specific RNA and cell wall structures. The third domain is the eukarya domain, which contains organisms that contain a true nucleus (called eucaryotes), which are fungi, protists, animals, and plants.

Further grouping under the system of domains includes groups based on kingdoms. There are six kingdoms, and they encompass the Animalia, Plantae, Fungi, Protista, Eubacteria, and Ancient bacteria (known as Archaebacteria). The Linnaeus system of taxonomy was the basis for all the developments and improvements that modern scientists came up with to organize the living world around us and will likely continue to be adapted as our knowledge base grows.


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