Linnaean taxonomy

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The title page of Systema Naturae, Leiden (1735) Linne-Systema Naturae 1735.jpg
The title page of Systema Naturae, Leiden (1735)

Linnaean taxonomy can mean either of two related concepts:


  1. the particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his Systema Naturae (1735) and subsequent works. In the taxonomy of Linnaeus there are three kingdoms, divided into classes, and they, in turn, into lower ranks in a hierarchical order.
  2. a term for rank-based classification of organisms, in general. That is, taxonomy in the traditional sense of the word: rank-based scientific classification. This term is especially used as opposed to cladistic systematics, which groups organisms into clades. It is attributed to Linnaeus, although he neither invented the concept of ranked classification (it goes back to Plato and Aristotle) nor gave it its present form. In fact, it does not have an exact present form, as "Linnaean taxonomy" as such does not really exist: it is a collective (abstracting) term for what actually are several separate fields, which use similar approaches.

Linnaean name also has two meanings: depending on the context, it may either refer to a formal name given by Linnaeus (personally), such as Giraffa camelopardalis Linnaeus, 1758, or a formal name in the accepted nomenclature (as opposed to a modernistic clade name).

The taxonomy of Linnaeus

In his Imperium Naturae, Linnaeus established three kingdoms, namely Regnum Animale, Regnum Vegetabile and Regnum Lapideum. This approach, the Animal, Vegetable and Mineral Kingdoms, survives today in the popular mind, notably in the form of the parlour game question: "Is it animal, vegetable or mineral?". The work of Linnaeus had a huge impact on science; it was indispensable as a foundation for biological nomenclature, now regulated by the nomenclature codes. Two of his works, the first edition of the Species Plantarum (1753) for plants and the tenth edition of the Systema Naturae (1758), are accepted as part of the starting points of nomenclature; his binomials (names for species) and generic names take priority over those of others. [1] However, the impact he had on science was not because of the value of his taxonomy.

Linnaeus' kingdoms were in turn divided into classes , and they, in turn, into orders , genera (singular: genus), and species (singular: species), with an additional rank lower than species, though these do not precisely correspond to the use of these terms in modern taxonomy. [2]

Classification of plants

His classes and orders of plants, according to his Systema Sexuale, were never intended to represent natural groups (as opposed to his ordines naturales in his Philosophia Botanica ) but only for use in identification. They were used for that purpose well into the nineteenth century. [3] Within each class were several orders. This system is based on the number and arrangement of male (stamens) and female (pistils) organs. [4]

Key to the Sexual System (from the 10th, 1758, edition of the Systema Naturae) SN-p837.jpg
Key to the Sexual System (from the 10th, 1758, edition of the Systema Naturae)
Kalmia is classified according to Linnaeus' sexual system in class Decandria, order Monogyna, because it has 10 stamens and one pistil Kalmia latifolia Great Smoky.jpg
Kalmia is classified according to Linnaeus' sexual system in class Decandria, order Monogyna, because it has 10 stamens and one pistil

The Linnaean classes for plants, in the Sexual System, were (page numbers refer to Species plantarum):

The classes based on the number of stamens were then subdivided by the number of pistils, e.g. Hexandria monogynia with six stamens and one pistil. [28] Index to genera p. 1201 [29]

By contrast his ordines naturales numbered 69, from Piperitae to Vagae.

Classification for animals

The 1735 classification of animals Linnaeus - Regnum Animale (1735).png
The 1735 classification of animals

Only in the Animal Kingdom is the higher taxonomy of Linnaeus still more or less recognizable and some of these names are still in use, but usually not quite for the same groups. He divided the Animal Kingdom into six classes, in the tenth edition, of 1758, these were:

Classification for minerals

His taxonomy of minerals has long since dropped from use. In the tenth edition, 1758, of the Systema Naturae, the Linnaean classes were:

Rank-based scientific classification

This rank-based method of classifying living organisms was originally popularized by (and much later named for) Linnaeus, although it has changed considerably since his time. The greatest innovation of Linnaeus, and still the most important aspect of this system, is the general use of binomial nomenclature, the combination of a genus name and a second term, which together uniquely identify each species of organism within a kingdom. For example, the human species is uniquely identified within the animal kingdom by the name Homo sapiens. No other species of animal can have this same binomen (the technical term for a binomial in the case of animals). Prior to Linnaean taxonomy, animals were classified according to their mode of movement.

Linnaeus's use of binomial nomenclature was anticipated by the theory of definition used in Scholasticism. Scholastic logicians and philosophers of nature defined the species man, for example, as Animal rationalis, where animal was considered a genus and rationalis (Latin for "rational") the characteristic distinguishing man from all other animals. Treating animal as the immediate genus of the species man, horse, etc. is of little practical use to the biological taxonomist, however. Accordingly, Linnaeus's classification treats animal as a class including many genera (subordinated to the animal "kingdom" via intermediary classes such as "orders"), and treats homo as the genus of a species Homo sapiens, with sapiens (Latin for "knowing" or "understanding") playing a differentiating role analogous to that played, in the Scholastic system, by rationalis (the word homo, Latin for "human being", was used by the Scholastics to denote a species, not a genus).

A strength of Linnaean taxonomy is that it can be used to organize the different kinds of living organisms, simply and practically. Every species can be given a unique (and, one hopes, stable) name, as compared with common names that are often neither unique nor consistent from place to place and language to language. This uniqueness and stability are, of course, a result of the acceptance by working systematists (biologists specializing in taxonomy), not merely of the binomial names themselves, but of the rules governing the use of these names, which are laid down in formal nomenclature codes.

Species can be placed in a ranked hierarchy, starting with either domains or kingdoms. Domains are divided into kingdoms. Kingdoms are divided into phyla (singular: phylum) for animals; the term division, used for plants and fungi, is equivalent to the rank of phylum (and the current International Code of Botanical Nomenclature allows the use of either term). Phyla (or divisions) are divided into classes , and they, in turn, into orders , families , genera (singular: genus), and species (singular: species). There are ranks below species: in zoology, subspecies (but see form or morph ); in botany, variety (varietas) and form (forma), etc.

Groups of organisms at any of these ranks are called taxa (singular: taxon ) or taxonomic groups.

The Linnaean system has proven robust and it remains the only extant working classification system at present that enjoys universal scientific acceptance. However, although the number of ranks is unlimited, in practice any classification becomes more cumbersome the more ranks are added. Among the later subdivisions that have arisen are such entities as phyla, families, and tribes, as well as any number of ranks with prefixes (superfamilies, subfamilies, etc.). The use of newer taxonomic tools such as cladistics and phylogenetic nomenclature has led to a different way of looking at evolution (expressed in many nested clades) and this sometimes leads to a desire for more ranks. An example of such complexity is the scheme for mammals proposed by McKenna and Bell.


Over time, understanding of the relationships between living things has changed. Linnaeus could only base his scheme on the structural similarities of the different organisms. The greatest change was the widespread acceptance of evolution as the mechanism of biological diversity and species formation, following the 1859 publication of Charles Darwin's On the Origin of Species . It then became generally understood that classifications ought to reflect the phylogeny of organisms, their descent by evolution. This led to evolutionary taxonomy, where the various extant and extinct are linked together to construct a phylogeny. This is largely what is meant by the term 'Linnaean taxonomy' when used in a modern context. In cladistics, originating in the work of Willi Hennig, 1950 onwards, each taxon is grouped so as to include the common ancestor of the group's members (and thus to avoid phylogeny). Such taxa may be either monophyletic (including all descendants) such as genus Homo , or paraphyletic (excluding some descendants), such as genus Australopithecus .

Originally, Linnaeus established three kingdoms in his scheme, namely for Plants, Animals and an additional group for minerals, which has long since been abandoned. Since then, various life forms have been moved into three new kingdoms: Monera, for prokaryotes (i.e., bacteria); Protista, for protozoans and most algae; and Fungi. This five kingdom scheme is still far from the phylogenetic ideal and has largely been supplanted in modern taxonomic work by a division into three domains: Bacteria and Archaea, which contain the prokaryotes, and Eukaryota, comprising the remaining forms. These arrangements should not be seen as definitive. They are based on the genomes of the organisms; as knowledge on this increases, classifications will change. [30]

Representing presumptive evolutionary relationships, especially given the wide acceptance of cladistic methodology and numerous molecular phylogenies that have challenged long-accepted classifications, within the framework of Linnaean taxonomy, is sometimes seen as problematic. Therefore, some systematists have proposed a PhyloCode to replace it.

See also

Related Research Articles

Carl Linnaeus Swedish botanist, physician, and zoologist

Carl Linnaeus, also known after his ennoblement 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, and his name is rendered in Latin as Carolus Linnæus.

Taxonomy (biology) Science of naming, defining and classifying organisms

In biology, taxonomy is the scientific study of naming, defining (circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum, class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a ranked system known as Linnaean taxonomy for categorizing organisms and binominal nomenclature for naming organisms.

Genus /ˈdʒiː.nəs/ is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.

Binomial nomenclature System of identifying species of organisms using a two-part name

In taxonomy, binomial nomenclature, also called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name or a scientific name; more informally it is also called a Latin name.

In biological classification, class is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order.

In biological classification, the order is

  1. a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. The well-known ranks in descending order are: life, domain, kingdom, phylum, class, order, family, genus, and species, with order fitting in between class and family. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order.
  2. a taxonomic unit in the rank of order. In that case the plural is orders.
Taxon Group of one or more populations of an organism or organisms which have distinguishing characteristics in common

In biology, a taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping.

In biology, a common name of a taxon or organism is a name that is based on the normal language of everyday life; and is often contrasted with the scientific name for the same organism, which is Latinized. A common name is sometimes frequently used, but that is not always the case.

<i>Systema Naturae</i> Major work by Swedish botanist Carolus Linnaeus

Systema Naturae is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomenclature, was partially developed by the Bauhin brothers, Gaspard and Johann, 200 years earlier, Linnaeus was first to use it consistently throughout his book. The first edition was published in 1735. The full title of the 10th edition (1758), which was the most important one, was Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis or translated: "System of nature through the three kingdoms of nature, according to classes, orders, genera and species, with characters, differences, synonyms, places".

<i>Species Plantarum</i> Book by Carl Linnaeus

Species Plantarum is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the starting point for the naming of plants.

Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms. To an end-user who only deals with names of species, with some awareness that species are assignable to families, it may not be noticeable that there is more than one code, but beyond this basic level these are rather different in the way they work.

<i>Philosophia Botanica</i>

Philosophia Botanica was published by the Swedish naturalist and physician Carl Linnaeus (1707–1778) who greatly influenced the development of botanical taxonomy and systematics in the 18th and 19th centuries. It is "the first textbook of descriptive systematic botany and botanical Latin". It also contains Linnaeus's first published description of his binomial nomenclature.

Taxonomic rank Level in a taxonomic hierarchy

In biological classification, taxonomic rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.

Cultivated plant taxonomy

Cultivated plant taxonomy is the study of the theory and practice of the science that identifies, describes, classifies, and names cultigens—those plants whose origin or selection is primarily due to intentional human activity. Cultivated plant taxonomists do, however, work with all kinds of plants in cultivation.

<i>Genera Plantarum</i>

Genera Plantarum is a publication of Swedish naturalist Carl Linnaeus (1707–1778). The first edition was issued in Leiden, 1737. The fifth edition served as a complementary volume to Species Plantarum (1753). Article 13 of the International Code of Nomenclature for algae, fungi, and plants states that "Generic names that appear in Linnaeus' Species Plantarum ed. 1 (1753) and ed. 2 (1762–63) are associated with the first subsequent description given under those names in Linnaeus' Genera Plantarum ed. 5 (1754) and ed. 6 (1764)." This defines the starting point for nomenclature of most groups of plants.

10th edition of <i>Systema Naturae</i> Book by Carl Linnaeus

The 10th edition of Systema Naturae is a book written by Swedish naturalist Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature. In it, Linnaeus introduced binomial nomenclature for animals, something he had already done for plants in his 1753 publication of Species Plantarum.

<i>Critica Botanica</i>

Critica Botanica was written by Swedish botanist, physician, zoologist and naturalist Carl Linnaeus (1707–1778). The book was published in Germany when Linnaeus was twenty-nine with a discursus by the botanist Johannes Browallius (1707–1755), bishop of Åbo. The first edition was published in July 1737 under the full title Critica botanica in qua nomina plantarum generica, specifica & variantia examini subjiciuntur, selectoria confirmantur, indigna rejiciuntur; simulque doctrina circa denominationem plantarum traditur. Seu Fundamentorum botanicorum pars IV Accedit Johannis Browallii De necessitate historiae naturalis discursus.

<i>Svenska Spindlar</i> 1757 arachnology text by Carl Alexander Clerck

The book Svenska Spindlar or Aranei Svecici is one of the major works of the Swedish arachnologist and entomologist Carl Alexander Clerck and was first published in Stockholm in the year 1757. It was the first comprehensive book on the spiders of Sweden and one of the first regional monographs of a group of animals worldwide. The full title of the work is Svenska Spindlar uti sina hufvud-slägter indelte samt under några och sextio särskildte arter beskrefne och med illuminerade figurer uplysteAranei Svecici, descriptionibus et figuris æneis illustrati, ad genera subalterna redacti, speciebus ultra LX determinati, and included 162 pages of text and six colour plates. It was published in Swedish, with a Latin translation printed in a slightly smaller font below the Swedish text.

12th edition of <i>Systema Naturae</i>

The 12th edition of Systema Naturae was the last edition of Systema Naturae to be overseen by its author, Carl Linnaeus. It was published by Laurentius Salvius in Holmiæ (Stockholm) in three volumes, with parts appearing from 1766 to 1768. It contains many species not covered in the previous edition, the 10th edition which was the starting point for zoological nomenclature.


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