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Taxonomy- Definition, Classification, Hierarchy, Examples

Taxonomy- Definition, Classification, Hierarchy, Examples

Taxonomy Definition

Taxonomy, a branch of biology, uses a classification system to group all living organisms together. Carl Linnaeus, a Swedish botanist, developed it in the 18th century and it is being used today. Linnaeus invented binomial nomenclature, naming all kinds of organisms with genus and species names. The taxonomic hierarchy is a system with eight stages, ranging from generic to particular. A domain is a group of things like a kingdom or phylum or class or even an order or family or genus or species.

Taxonomic Hierarchy

A taxon is a term used in biology to describe a group of related species. Specifically or generically are the two ways to frame this idea. To put it another way, all humans and other primates are a taxon at the order level, as they belong to the order Primates. Since they are all of the same species, we may call them both taxons at the species level. In the taxonomic hierarchy, different levels of abstraction are represented by distinct taxonomic ranks, such as species and orders. According to the information provided below, the taxonomic hierarchy is comprised of taxonomic ranks.


A domain is an organism’s highest (and most general) level of classification. Linnaeus invented some of the taxonomic ranks, but not the domain one. The term “domain” was first used in academic writing in 1990, more than 250 years after Linnaeus’ classification system was created in 1735. Archaea, Eukaryota, and Prokaryota are the three major groups of organisms that make up all of life. There are single-celled organisms known as archaea that can survive in both harsh and temperate environments. Eukaryota, which comprises all other species on the planet, has its nearest living cousin in a bacterium or archaeon.

Taxonomy uses lowercase capitalization only for species. This allows the general public to distinguish between bacteria (the creatures; could refer to every bacteria or only two specific species) and Bacteria (the domain, which includes all bacteria).


The kingdom used to be the highest taxonomic level before domains were introduced. Before, the kingdoms were divided into the following: Animalia; Plantae; Fungi; Protista; Archaea; and Bacteria. Everybody’s combined into one now (Archaea and Bacteria were manytimes arranged into one kingdom, Monera). Classifications like Protista, on the other hand, are a bit sloppy. There are many eukaryotic species outside of mammals, plants, and fungus that are categorised as protists. These organisms, on the other hand, aren’t particularly linked. Despite the fact that scientists disagree on how to designate kingdoms, the debate continues. Researchers are always modifying it; in 2015, they proposed separating Protista under kingdom Protozoa and Chromista. They are continually revising it.


kingdoms take precedence over phyla (plural: phyla). However, phylums do not have the level of specialisation that classes possess. The Animalia kingdom is home to 35 different phyla, such as Chordata (all animals with a dorsal nerve cord), Porifera, and Arthropoda, to name a few (arthropods).


Linnaeus introduced phyla, a more precise classification, in the late 18th century. There are 108 different suborders within the kingdom Animalia, including Mammalia (animals) and Reptilia (reptiles). There are similarities between Linnaeus’ Animalia classes and the ones that are currently in use, however the classification that Linnaeus used for plants was based on floral arrangement rather than similarity. Linnaeus’ classifications have largely been replaced by more modern classifications.


The terms “class” and “order” have distinct connotations. Lepidoptera, for example, is still classified according to Linnaeus’ standards (the order of butterflies and moths). Depending on how creatures are classified —there are anywhere from 19 to 26 different orders of mammals. In the Mammalia family tree, there are many different kinds of animals that live in the Mammalia order: Cetaceans, Carnivores, Primates, and Chiroptera).


The use of the word “family” significantly reduces the scope of the discussion. In the Carnivora, there are several families such the Canidae (which includes canines such as dogs), Felidae (which includes felines such as cats and urchins), and Mephitidae and Ursidae (bears). Caterpillars are classified into 12 different families in the Carnivora.


Genus, as opposed to family, has a very narrow definition. The first part of a scientific name is the binomial nomenclature, followed by the species name. The scientific name must always be italicised, even if the species name is lowercase. Italics are used only for the taxonomic levels of genus and species. In the scientific community, we are known as Homo sapiens. Sapiens is the scientific term for the genus Homo. There are no longer any other known subspecies of Homo. While most were distant cousins to modern humans, some like Homo erectus were family members of our species. In addition to the Neanderthals, there were other hominins like the Australopithecus who coexisted with us and interacted with us.

Taxonomy- Definition, Classification, Hierarchy, Examples


The largest taxonomic class, species can be subdivided into smaller classes, although not every species have distinct enough morphologies to be recognised as separate taxa. Only a small fraction of the planet’s estimated 8.7 million types of creatures have been found and catalogued. In the case of species names and genus names, the former can be applied to more than one type of organism. As an example, Ursus americanus is the scientific name for the North American black bear, whereas Bufo americanus is the scientific name for the North American toad. Never use all capital letters while writing the species’ name in italics. It’s a little difficult to understand as it’s the only taxonomic rank that doesn’t utilise capital letters. From the first full use in scientific journals, where it is often used, the species name is abbreviated with the initial letter of the genus name and the complete species name. In the scientific community, Homo sapiens is referred to as simply H.

Examples of Taxonomy

Humans are classified scientifically as follows:

  • Domain: Eukaryota
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Primates
  • Family: Hominidae
  • GenusHomo
  • Species: sapiens

An additional illustration of taxonomy can be seen in the picture below, which depicts the classification of the red fox (Vulpes vulpes) (sometimes the genus and species names are the similar, even though these are two different ranks).

As an example, “Dear King Philip Came Over For Good Spaghetti” is a clever mnemonic device for remembering the taxonomic hierarchy’s order.

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