Taxonomic Hierarchy - Definition, Classification, Example, Categories

According to the history of Biological Classification, Aristotle first attempted scientific classification of animals, and later, Carolus Linnaeus introduced the Taxonomic Hierarchical System of Classification and Binomial Nomenclature, which are still used today globally. Organisms are grouped into ranked categories such as Kingdom, Phylum, Class, Order, Family, Genus, and Species. The systematic arrangement of living organisms of diversity based on their features is called the Taxonomic Hierarchy. Taxonomy is a branch of Biology that refers to the process of classifying different living species.

This Story also Contains

1. What is Taxonomic Hierarchy?
2. Taxonomic Hierarchy Categories
3. Examples of Taxonomic Hierarchy
4. Importance of Taxonomic Hierarchy
5. Recommended Video on Taxonomic Hierarchy

Taxonomy is a form of classification in the study of living organisms in which they are grouped into a series of ever-decreasing classes. This basic taxonomical structure consists of the ranks such as domain, kingdom, phylum, class, order, family, genus, and species. The Binomial Nomenclature and Taxonomic Hierarchy system laid the foundation for modern taxonomy used by scientists today.

What is Taxonomic Hierarchy?

The concept of taxonomic hierarchy means a simple and clear classification of the Earth’s diversity for effective scientific discussion and investigations. The word “taxonomic” is a Greek word meaning:

• “taxis” - meaning arrangement

• “nomos” - meaning method

Taxonomic Hierarchy is the arrangement method of diversity present globally. Modern principles of taxonomy are primarily associated with Carl Linnaeus, who worked in the 18th century and introduced the Principles of Binomial Nomenclature and the Hierarchical System of Classification of organisms into taxons.

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Taxonomic Hierarchy Categories

Under the Taxonomic Hierarchical System of Classification, organisms are grouped into ranked categories such as Kingdom, Phylum, Class, Order, Family, Genus, and Species. The taxonomic hierarchy is discussed below:

Domain

• These are the major groupings of living organisms at the broadest level of taxonomic rank, where the differences in cells and hereditary material are most marked.

• It categorises life into three broad groups: this includes; Archaea (ancient bacteria-like organisms), Bacteria (true bacteria), and Eukarya (organisms with complex cells containing nuclei).

• Thus, each domain consists of numerous organisms, most of which possess certain traits that set them apart from the organisms within other domains.

Kingdom

• This system organises life into the Five Kingdom Classification based on fundamental features that can include such things as cell structure, food, and how it reproduces.

• These kingdoms are Monera - popularly known as prokaryotic organisms, mostly consisting of single-celled eukaryotes, Fungi which are eukaryotes but decomposers, Plantae, which are photosynthetic eukaryotes and lastly, Animalia which are eukaryotic, mainly consisting of organisms that feed on organic matter.

• Some examples of the classification include the Kingdom Plantae, which includes all green plants, and the Kingdom Animalia, which includes animals from sponges to humans.

Phylum

• A phylum is another rank, or taxonomic category, that is located above the class but below the kingdom and is characterised by a general body plan and other major structural features of organisms.

• Many organisms belonging to the same phylum can be compared in terms of their level of complexity, and their evolutionary development may also be similar in many ways, and therefore demonstrate several similarities.

• For example, Chordata consists of animals with a notochord, such as mammals, birds, and fish, while Arthropoda consists of invertebrates with outside coverings, segmented bodies, and/or limbs with joints- for example, insects, spiders, and crustaceans.

Class

• In systematics, a class is a taxon that is higher than an order and lower than a phylum. For example, Mammalia (which includes mammals) and Aves, which are birds, are both biological classes used in the classification of animals.

• Individuals that belong to a certain class are categorized according to their similarities with certain characteristics, including the body structure, the manner of reproduction, and genes.

Order

• Order is a taxon, next to the family and above the class. Some of them are carnivora, which is the biological suborder of animals that have a carnivorous diet, and primates, which is also a biological suborder and mainly consists of animals that are primarily of nutrients.

• Orders are distinguished based on other, more definite similarities and the evolutionary characteristics that separate them from other orders of the same class.

Family

• A family belongs to a higher rank than the genus and at the same time belongs to a lower rank as compared to the order. It clusters related genera that are similar in nature and genesis of species.

• Dogs, wolves, and foxes belong to the family Canidae, while cats, lions and tigers belong to Felidae with the indications being based on morphological and genetic differences unique to each family.

Genus

• The genus is a hierarchy level that contains species that are genetically related and share some or many similarities; for example, lions and tigers belong to the genus Panthera.

• They help in grouping species into easily manageable sections to help in the study of the relative relationship between the species as well as forecast other characteristics that they could possess.

Species

• The most specific classification level is species, which are groups of organisms that can breed and produce viable offspring.

• In binomial nomenclature, every species has two distinguishing names, which are the genus and specific epithet for example Homo sapiens for the human species.

Examples of Taxonomic Hierarchy

The taxonomic ranks with real-life examples help in identifying and categorizing organisms more accurately. Below is a clear example of the taxonomic classification of humans, showcasing all levels from the Animal Kingdom to the Species sapiens.

Importance of Taxonomic Hierarchy

The Taxonomic Hierarchy plays a crucial role in the scientific classification of living organisms, helping biologists understand and organise Earth's vast biodiversity. The importance of taxonomic hierarchy is discussed below:-

Understanding Biodiversity and Evolutionary Relationships

• The process of classification also allows organising an enormous number of species and gives a better understanding of the concept of diversity.

• It shows the living organisms’ origins and their relatives and depends on whose tree one is looking at, it can also show that living organisms are related from a common source.

• They help in discovering the history of the evolution of life on the planet and contribute to understanding the processes governing biodiversity.

Applications in Agriculture, Medicine, and Conservation

• In agriculture, taxonomy is used for the identification and categorisation of crop pests and other helpful organisms vital for defining strategies of pest control and increasing crop productivity.

• In medicine, thus, the taxonomy of pathogens and vectors helps the doctor in diagnosing, management, and prevention.

• In this case, taxonomy establishes the degrees of species threatened by the process of extinction, hence general conservation efforts to protect species of this status.

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Recommended Video on Taxonomic Hierarchy