The word taxonomy is derived from the Greek words taxis meaning arrangement and nomos meaning law. The branch of botany that deals with the basis, purpose and principles of classification of plants is called taxonomy. According to scientist E. Mayer (1969), Taxonomy is the theory and practice of classification. French botanist A. P. de Candolle first used the term taxonomy. The Swedish scientist Carolus Linnaeus contributed the most to the taxonomy of plants. That is why he is called Father of Taxonomy.
Basic principles of taxonomy
1. Taxonomic character: The characteristics by which one taxon is distinguished from another taxon are called taxonomic characters. The characteristics of each plant are carefully observed and recorded to make the taxonomy. Taxonomic characteristics of plants are reproductive characteristics, genetic characteristics, chemical characteristics, morphological characteristics, physiological characteristics, behavioral characteristics, ecological characteristics etc. These features are properly mentioned during classification. Dr. Siddiq Publications
2. Identification: Each plant is accurately identified for taxonomic purposes. Similarities and differences between them are determined on the basis of taxonomic characteristics. Identification may be – genetically unbalanced samples, members grown in unfavorable conditions, hybrids, recently published articles, new species etc. The collected specimens are then compared with the descriptions of other plants. A comprehensive understanding of subspecies, species, synopsis, reviews, catalogs, revisions, monographs, taxonomy, ethnography, field guides and checklists is required for accurate identification.
3. Categorization: According to the course of evolution, plants with similar characteristics are placed in a specific category. The hierarchy has a total of 7 categories or ranks. These are – Kingdom, Phylum, Class, Order, Family, Genus and Species. Among them, Kingdom is the largest and Species is the smallest.
4. Nomenclature: Making, explaining and applying principles related to the scientific name of any plant or animal is called nomenclature. Siddique Publications
(i) Binomial nomenclature: Binomial nomenclature is the giving of a specific scientific name to a particular species by two terms or words adding the species name to the end of the generic name as per ICBN or ICZN principles. In 1753, the Swedish naturalist Carolus Linnaeus introduced the system of binomial naming of organisms.
(ii) Tripad nomenclature: According to the International Principles of Nomenclature of Organisms, the name given to an organism by three terms or words genus, species and subspecies is called tripad nomenclature. German scientist Hermann Schlegel (1884) introduced tripartite nomenclature. Like- Naja naja naja.
5. Conservation: Plant samples collected in different ways should be properly preserved. Leaves, flowers, fruits, seeds, stems, roots etc. of plants are collected as samples. All these samples can be stored in dry or liquid medium. Formalin and alcohol are the best liquid preservation mediums. Various museums, conservatories, colleges and universities of the country store plant specimens in public and private ways.
Units of classification
The steps or levels into which animals are placed are called taxonomic units. Each level or unit of animal classification is called a taxon. The International Code of Zoological Nomenclature (ICZN) uses 7 recognized units or taxa of animals. During taxonomy, taxa are arranged in a specific structure. This is called the taxonomic hierarchy.
1. Species: Species is the smallest unit of taxonomy. This is called the basic unit. A group of organisms with the most physical similarities, capable of producing fertile offspring by sexual intercourse among themselves but unable to produce fertile offspring by sexual intercourse with other groups, is called a species. Behavioral and ecological characteristics of species are called niches. Species can be subdivided into subspecies, varieties etc. if necessary.
According to taxonomist E. Mayer (1969), a species is an interbreeding group of organisms that are reproductively isolated from the nearest similar group. John Ray first used the term species in 1686. Each species has a scientific name. The scientific name of all rice in the world is Oryza sativa.
2. Genus: Genus is the second unit of classification or taxon. A genus consists of several closely related species. Artocarpus genus consists of closely related species such as Jackfruit (Artocarpus heterophyllus), Chaplasha (Artocarpus chaplasha), Dewa (Artocarpus lacucha).
3. Family: Family is the third unit of taxonomy or taxon. A clan is made up of several closely related clans. aceae is added at the end of the plant family name. The family Moraceae is formed by the closely related genera Artocarpus, Ficus, Morus etc.
4. Order: Class is the fourth unit of taxonomy or taxon. Classes are made up of several closely related tribes. Ales are added to the end of plant class names. Sapindales, Morales, Malvales etc. are classes.
5. Class: A class is a higher unit of taxonomy or taxon. Classes are made up of several closely related classes. opsida is added to the end of plant class names. Magnoliopsida, Liliopsida etc. are classes.
6. Division: A division is a higher unit or taxon of taxonomy. Sections are made up of several closely related categories. Phyta is added at the end of the plant division.
7. Kingdom: All the plants of the world belong to the Plantae kingdom.
Necessity of classification
1. Theoretical necessity
(i) Gaining the identity of the living world: If you can get an idea about an animal of a group through taxonomy, you can get an idea about all the animals of that group. That is, taxonomy helps to know all the animals in a simple way.
(ii) Know about fauna: There are millions of species of animals in the world. Through taxonomy one learns about the fauna in less time and with less effort.
(iii) Identification of animals: Any branch of zoology requires accurate identification of animals for research, education, human welfare etc. Animals can be easily identified through taxonomy.
(iv) Knowledge of Animals: Our knowledge of animals can be summed up through taxonomy.
(v) Concise knowledge of animals: Taxonomy helps to summarize knowledge related to animals.
(vi) Identification of new species: Taxonomic knowledge is essential for identification of new species and their placement at various stages. New species cannot be identified without taxonomy.
(vii) Public recognition: Knowledge of taxonomy is essential in providing international public recognition of animals.
(viii) Determining the origin of animals: Modern taxonomy helps in determining the origin of animals and indicates the course of evolution.
(ix) Determination of ethnic relationship: The ethnic relationship of animals can be determined through taxonomy.
(x) International identification: Knowledge of taxonomy plays an important role in providing easy international identification of all the animals of the world.
(xi) Identification of herbivores: Identification of herbivores requires knowledge of taxonomy.
(xii) Development of improved breeds: Improved and disease resistant breeds of animals and plants are developed through artificial breeding. In this case knowledge of taxonomy is a must.
(xiii) Conservation of wild animals: Knowledge of taxonomy is necessary for control and conservation of wild animals.
(xiv) Selection of economic animals: Economic animals can be selected through classification.
(xv) Artificial Breeding: Genetic characteristics are taken into account in the classification of organisms. Knowledge of taxonomy facilitates creation of new and improved breeds of animals and birds through artificial breeding.
(xvi) Agricultural Development: Knowledge of taxonomy is essential for agricultural education, animal health improvement, pest control and crop improvement.
(xvii) Animal Husbandry: Taxonomy is required for rearing and care of poultry and cattle.
(xviii) Food chain: By means of taxonomy one can get an idea about the extinction of animals. Therefore, classification of animals is necessary to preserve animals and maintain the food chain. (xix) Position of animals: Classification is necessary to know the position of any animal in the animal kingdom.
(xx) Identification of Extinct Animals: Animals that have become extinct in the past are found as fossils. Their correct identification can be obtained by observing fossils and classifying them.
(xxi) Conservation of environment: Selection of plants suitable for the environment of any region can be done using the knowledge of taxonomy.
(xxii) Concept of Evolution: Through taxonomy, an idea of the course of evolution of organisms is obtained.
(xxiii) Development of new branches of science: Knowledge of taxonomy is essential for development of new branches of science especially biotechnology, biogeography, biomaterials etc.
2. Applied necessity
(i) Conservation of wild animals: Knowledge of taxonomy is necessary for control and conservation of wild animals.
(ii) Artificial Breeding: Genetic characteristics are taken into account in the classification of organisms. Knowledge of taxonomy facilitates creation of new and improved breeds of animals and birds through artificial breeding.
(iii) Agricultural Development: Knowledge of taxonomy is essential for agricultural education, animal health promotion, pest control and crop development.
(iv) Animal Husbandry: Taxonomy is required for rearing and care of poultry and cattle.
(v) Utilization of animals: By knowing the behavior and nature of animals and classifying them, the beneficial and harmful roles of animals can be known and they can be used accordingly.
(vi) Food chain: Taxonomy can provide an advance understanding of animal extinction. So animal taxonomy is necessary to maintain animal conservation and food chain.
(vii) Sorting of animals: Through classification it is known which are beneficial and which are harmful.