Taxonomic Hierarchy: Definition, Principles, Taxonomic categories, and Taxon
The concept taxonomy was first provided by De Candolle in 1813. The Greek term taxis which means arranging and nomos which means rule are combined to form taxonomy. Thus taxonomy is described as the organization of living creatures such as flora and fauna into a categorization framework. Taxonomy is the art of naming, describing, and arranging species on the earth. Taxonomy is the study of the classifications recognition and naming of living beings.
The study of categorization principles and techniques such as characterization, identification, nomenclature, and classification is known as taxonomy
Characterization: The organisms to be studied are described for their characters.
Classification: It is the placing of an organism or a group of organisms in particular groups for their fundamental characters according to the system of classification
Identification: It is the finding of the correct name and place of an organism in a system of classification.
Nomenclature: It is the science of providing distinct and proper names to an organism so that organisms can be easily recognized.
In biological classification, living organisms are placed in levels or ranks, or categories. Each rank or level of classification in which living organisms are placed is called a Taxonomic Category. It may also be defined as groups in which living organisms are placed together based on similarities or characters.
The living beings are placed in seven taxonomic categories which are as follows.
- Plyllum (animals) and Division (plants)
Note: Always keep in mind that the taxonomic categories you employ must be mandatory
The easy way to remember taxonomic categories is
- Keep ——– Kingdom
- Pots——— Plyllum (animals) and Division (plants)
- Clean——- Class
- Or———– Order
- Gets——- Genus
Species in taxonomy
The term species was coined by John Ray and The biological concept of species was given by Ernest Mayr.Davis in 1978 called species building bricks in biological classification. Species is the basic unit and lowest category of classification in the taxonomic hierarchy recognized by all people of the world.
A species is a collection of individuals who are substantially similar to one another and can usually interbreed and produce fertile offspring. Species can also be defined as the group of individuals having many characteristics in common and are ranking below the genus. the individuals also have the same ancestor and have the same gene pool Examples All human beings, All dogs, etc
Note: there are some exceptions in species, Mule is a hybrid obtained from male Donkey and Female Horse.
Question: Whether Species are Genetically open or closed systems?
ANS: According to the Biological concept reproduction between two different species is not possible, thus we say that it is a closed system
Genus in taxonomy
Genus is a category in the taxonomic hierarchy that includes more than one similar species having a common ancestor. the species included in a genus show more characteristics than the species in other genera. Examples Tiger, Lion, and Leopard belong to the same Genus Panthera and have different species.
Note: The groups of common characters in a species of Genus are called Correlated characters.
Family in a taxonomy
The term family was first given by A.L. de Jussieu in the book Genera Plantarum. In 1789 where he grouped Genera under one head i.e. Family. A.L. de Jussieu is also known as the “Father of the Familial concept” in flowering plants.
Family is a category in a taxonomic hierarchy that includes more than one similar genera and having a common ancestor. we know that solanum, Petunia, Datura, is grouped in the same family Solanaceae. All Pulses belong to the family Leguminaceae.
Order in a Taxonomy
Order is a category in the Taxonomic Hierarchy which includes one or more related similar families having a common ancestor and some common characters or features. Family Felidae (cats) and Family Canidae(dogs) are placed in the same Order Carnivora.
Class in Taxonomy
Class is a category in the taxonomic Hierarchy which includes one or more related similar orders having a common ancestor and having some common features or characters. For example, the Order Carnivora, Chiroptera, Rodentia, and Primates are placed in the same Class Mammalia. They have few characters in common i.e the presence of mammary glands and hairs.
Phylum/Division in Taxonomy
It is a category in the taxonomic hierarchy which includes one or more closely linked similar classes having a common ancestor. Phylum Chordata includes class Pisces Amphibia, Mammalia, because of the presence of the notochord, dorsal hollow nervous system, and pharynx perforated by gill slits.
kingdom in Taxonomy
It is a unique and diverse group. It is the highest taxonomic category encompassing all related phyla (animals) or divisions (plants). we know in this category all animals are marked as members of the animal kingdom and plants are treated as members of the kingdom plant. Always keep in mind that Similarities go on decreasing from Species to Kingdom.
when all the Taxonomic categories are arranged in a proper systematic manner then we say we have arranged taxonomic categories in a Hierarchy. Thus Taxonomic Hierarchy is defined as the systematic orderly arrangement of different categories.
Normally we arrange them into largest/biggest to smallest or smallest to largest/biggest.
Ascending order starts from Species, Genus, Family, Order, Phylum/Division, and Kingdom.
Descending order starts from Kingdom, Phylum/Division, Order, Family, Genus, Species.
Note: Carl Linnaeus gave certain categories such as Species, Genus, Order, and Variety. Later on, some new categories were given such as Kingdom, Phylum, and Family. when we systematically arrange them in taxonomic Hierarchy Variety was dropped.
Taxon: It means a cluster of individuals grouped based on the sharing of features in common.