Taxonomy: Definition, History & Features

Taxonomy: Do you know there are millions of living organisms, and all of them cannot be studied individually? Describing, identifying, naming, and classifying them in an organized manner leads to proper understanding. These come under Taxonomy. Who is the father of Taxonomy? Who coined the term Taxonomy? Have you heard about the scientist Carolus Linnaeus who was a person who introduced two kingdom classifications? ‌This‌ ‌article covers‌ ‌the‌ definition of taxonomy, taxonomic hierarchy, ‌and‌ ‌much‌ ‌more.‌ ‌Read‌ ‌on‌ ‌to‌ ‌find‌ ‌out‌ ‌more‌ ‌interesting‌ ‌facts‌ ‌about‌ ‌the‌ Taxonomy.

Define Taxonomy

Taxonomy is the branch of biology which deals with the study of the identification, classification, and naming of an organism. Taxonomy (Taxis – arrangement, nomos – law) deals with the identification, nomenclature, and classification of organisms.

What is Taxonomy?

To understand the definition of Taxonomy, we need to understand some of the specific terminologies like identification, classification, and nomenclature or naming.
If an organism is considered living, it should show or exhibit the life processes such as growth, metabolic activities, cellular organization, reproduction, response to stimuli, etc. So, to identify a particular organism, we need to know its information or name.

What is Nomenclature?

The system of giving distinct names to an organism is termed Nomenclature.
The scientific naming of an organism using two names is called Binomial Nomenclature. \({\rm{C}}.\) Linnaeus established the practice of binomial nomenclature.

What is Identification?

Finding out the correct place and correct name of the organism is termed as identification.

What is Classification?

It is the process of grouping organisms into convenient categories on the basis of some of the easily observable character is called classification.

Who is the Father of Taxonomy, and Who Coined the Term Taxonomy?

Carolus Linnaeus is regarded as the father of Taxonomy, and A P de Candolle in \(1813,\) coined the term Taxonomy.

History of Taxonomy

The scientific taxonomy, i.e., the classification of organisms, primarily occurred in the 18th century. However, the only basis that meets in the past to the early works only includes the descriptive of plants for agriculture and medicine purposes. Moreover, the early taxonomy was based on artificial systems or arbitrary criteria, including Linnaeus’s system.

The later systems were known as the natural systems, which include a more scientific taxonomy basis. The nature of these natural systems was based on pre-evolutionary thinking. Charles Darwin’s work on “Origin of Species” gave a more solid basis for the classification of organisms. The classification was based on the evolutionary relationships leading to phyletic systems or phylogenetic systems since \(1883.\)

Classical Taxonomy

It is also known as old taxonomy. In classical taxonomy, species is the basic unit, and it can be described on the basis of one or a few preserved specimens. Organisms are classified based on some limited features.

Modern Taxonomy/New Systematics

The concept of modern taxonomy was given by Julian Huxley \((1940).\) According to it, species are dynamic and ever-changing entities. Studies of organisms are done on a huge number of variations. It includes cytotaxonomy, numerical taxonomy, chemotaxonomy, etc.

Modern System of Classification

The kingdoms were coined towards the end of the 18th century before the Linnaean taxonomy translated into a variant of the animal and plant dendrograms on the origin of the genus. was published. The earliest works conceivable transmission of species between species were Erasmus Darwin’s 1796 Zoonomia and of Jean-Baptiste Lamarck Philosophie Zoological 1809.

Taxonomy Classification

The taxonomic classification system, which is also known as the Linnaean system after its inventor, Carl Linnaeus (or Carolus Linnaeus), a Swedish botanist, zoologist, and physician, uses a hierarchical model.

Taxonomic Categories/Taxonomic Hierarchy/Linnaeus Hierarchy

Classification is not a single-step process. Instead, it involves a hierarchy of steps in which each step represents a rank or category. Since the category is a part of the overall taxonomic arrangement, it is called the taxonomic category.

1. The taxonomic categories, which are always used in the hierarchical classification of organisms, are called obligate categories. They are kingdom, phylum or division, class, order, family, genus, and species.
2. The sub-categories like subspecies, sub-class, sub-family, etc., which facilitate more sound and scientific placement of various taxa, are called intermediate categories.
   The arrangement of taxonomic categories in descending order during the classification of an organism is called taxonomic hierarchy.
   It was first introduced by Linnaeus \((1751)\) and hence, it is also known as Linnaean Hierarchy.

What is a Taxon?

Taxon represents the rank of each category and is referred to as a unit of classification. The term ‘Taxon’ was first introduced by ICBN in \(1956.\)
According to Mayr \((1964)\), a taxon is a group of any rank that is sufficiently distinct to be worthy of being assigned a definite category.

Taxonomy Chart

The taxonomic categories consist of \(8\) taxa. The following is a brief description of the taxonomic ranks that make up the taxonomic hierarchy.

Fig: A Pyramidal Diagram of Taxonomy Chart

Let us now understand eight different taxa of the Taxonomic Hierarchy.

1. Species: It is the basic unit and the lowest taxonomic category, which consists of one or more individuals of a population. It was proposed by John Ray. An organism that can interbreed to produce fertile offspring is termed a species.
2. Genus: It is the larger unit of the taxon; it comprises a group of related species, which has more characters common compared to species of the genera. In other words, genera are the aggregates of closely related species.
3. Family: It comprises a group of related genera. In other words, family is the aggregate of closely related genera.
4. Order: It is a group of one or more related families that possess some similar correlated characters, which are lesser in number as compared to a family or genera.
5. Class: It is a major category, which includes related orders.
6. Phylum or Division: It is a taxonomic category higher than class and lowers in rank to the kingdom. The term ‘Phylum’ is used for animals, while ‘Division’ is commonly employed for plants. It consists of more than one class having some similar correlated characters.
7. Kingdom: It is the highest category in taxonomy. A kingdom includes all the organisms which share a set of distinguished characters.
8. Domain: A domain is the highest (most general) rank of organisms. Linnaeus did invent some of the taxonomic ranks, but he did not invent the domain rank, which is relatively new. The term domain was not used until \(1990,\) over \(250\) years after Linnaeus developed his classification system in \(1735.\) The three domains of life are Bacteria, Archaea, and Eukaryota.

Examples of Taxonomy

The scientific classification of humans is as follows:

Fig: A image Showing the Taxonomic Hierarchy of Homo sapiens

Alpha and Beta Taxonomy

The term “alpha taxonomy” is used today primarily to refer to the discipline of finding, describing and naming taxa. species in particular. In earlier literature, the term had a different meaning, referring to the products of morphological taxonomy and research through the late 19th century.

William Bertram Turrill introduced the term “alpha taxonomy” in a series of papers. Published in 1935 and 1937, in which he discussed the philosophy of the discipline of taxonomy and possible future directions. There is a growing willingness of taxpayers to consider their problems from a broader perspective, to examine closer co-possibilities. To operate with their cytological, ecological and genetics colleagues and to recognise that some modification or extension, among their objectives and methods, of a rigorous nature, may be desirable.

Turrill (1935) suggested that while accepting the old invariant taxonomy, structured, and simply designated “alpha” as broadly distant as possible, taxonomically and It is possible to have a glimpse built on the basis of physiological facts, and one in which “the place is found for all observational and experimental data relating, even if indirectly, to the constitution, subdivision, origin and behaviour of species and other taxonomic groups”. The idea can be, it may be said, never fully realized. However, they have a great deal of value acting as permanent stimulants, and if we have some, even vague, ideals of an “omega” classification we can move a little further down the Greek alphabet. Some of us amuse ourselves by thinking that we are now operating in a “beta” taxonomy.

Turrill thus clearly excludes alpha taxonomy from the various fields of study that he refers to as a whole, such as ecology, physiology, genetics and cytology. He excludes further phylogenetic reconstructions from the alpha taxonomy (pp. 365–366).

Later authors have used the term in a different sense, meaning the delimitation of species (not subspecies or taxa of other ranks), including whatever investigative techniques are available, and sophisticated computational or laboratory techniques. Thus, in 1968 Ernest Meyer defined “beta taxonomy” as a classification of ranks relative to species.

An understanding of the biological meaning of variation and the evolutionary origin of groups. The second stage of taxonomic activity of related species is even more important for the sorting (“taxa”) of species into groups of relatives and their arrangement in a higher hierarchical hierarchy. This activity is what the term classification denotes; It is also known as “beta taxonomy”.

Microtaxonomy and Macrotaxonomy

How species should be defined in a particular group of organisms gives rise to practical and theoretical problems called the species problems. The scientific task of deciding how to define a species has been called microtaxonomy. By extension, macrotaxonomy is the study of groups of higher taxonomic rank subgenera and above.

Taxonomic Aids

Taxonomic studies of plants, animals, microbes, and other organisms are highly useful in the field of agriculture, forestry, industry, and the study of biodiversity. Hence, the organism should be identified, classified and information of the organism should be stored for future references. This storehouse of information and specimens which helps in taxonomic studies are called taxonomic aids.

Some of the taxonomical aids are as follows:

Fig: Various Taxonomic Aids

Importance of Taxonomical Aids

Some of the importance of Taxonomical Aids are as follows:

1. These taxonomic aids help to store and preserve the information and also the specimens.
2. The collection of actual specimens of plant and animal species is essential and is the primary source of taxonomic studies.
3. These are also essential for training in systematics (it is the study of systematic arrangement of organisms) which is used for the classification of an organism.
4. Hence, taxonomic aids facilitate identification, naming, and classification of organisms using actual specimens collected from the fields and preserved as referrals in the form of herbaria, museums, etc.
5. Botanic gardens and zoological parks are also standard ex-situ conservation methods of plants and animals.

Features of Taxonomy

The feature of Taxonomy includes the following:
1. Morphological Characters: External features provide a primary and evident source for identifying the taxonomic characters. This includes general and internal morphological characters, genetic structure, embryology, and karyology.
2. Physiological Characters: These include metabolic factors, serological factors, body secretion, and genetic sterility factors.
3. Ecological Characters: It includes habitat, food, parasitic discrimination, and host reaction.

What is Ontology?

Ontology is the branch of philosophy that studies concepts such as existence, being, becoming, and reality.

Taxonomy vs Ontology

1. Taxonomy and ontology are very similar phenomena used in biology to describe and classify organisms. The main difference between taxonomy and ontology is that taxonomy is only based on hierarchy, but ontology is based on both hierarchy and other complex variations.
2. Taxonomy produces the hierarchical arrangement of different classes that represent entities. These classes are the different taxonomic ranks known as species, genus, family, order, class, phylum, kingdom, and domain. During ontology, the nature of the being, its existence, or reality is studied along with the hierarchy of the being.

Summary

Taxonomy is the scientific description, identification, classification, and naming of an organism. Through this article, we understood the importance of Taxonomic Hierarchy. Taxonomy is essential in knowing the names, their classification, and it helps identify the unknown species. Binomial nomenclature has both a generic name and a specific epithet. Hence, we can conclude that taxonomy is a vast and interesting topic.

FAQs

Q.1. Which taxon is the basic unit of classification?
Ans: The taxon – species is the basic unit of classification.

Q.2. What is Binomial Nomenclature?
Ans: It is the scientific style of writing a universally accepted name of an organism. This concept was given by Linneaus. Each name has two parts, the generic name, and specific epithet, signifying genus and species, respectively. For example, the name of the mango plant is Mangifera indica.

Q.3. What is Trinomial Nomenclature?
Ans: It is the style of the naming of an organism where there are three parts of the name, generic name, specific epithet, and subspecies name. This is not accepted in plant science but is found in zoology. For example, the modern man is called Homo sapiens sapiens.

Q.4. What is a herbarium?
Ans: It is the store of plant specimens. It is the collection of dried, pressed plant specimens which are arranged systematically according to the universally accepted system of classification.

Q.5. Who coined the term Taxonomy?
Ans: A P de Candolle, in \(1813,\) coined the term Taxonomy.

Q.6. Define species.
Ans: Species is a group of individuals which are morphologically and genetically identical and canly interbreed to produce fertile offspring in nature.

Q.7. What is taxonomy?
Ans: Taxonomy is the branch of biology which deals with the study of the identification, classification, and naming of an organism.

Q.8. Define types of classification in taxonomy.
Ans: The types of classification in taxonomy are artificial classification, natural classification, and phylogenetic classification.

Q.9. Who is considered the father of taxonomy?
Ans: Carolus Linnaeus is considered the father of taxonomy.

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