Nomenclature is the system of naming organisms scientifically to ensure uniformity and avoid confusion.

1.1. Principles of Nomenclature

  • Governed by International Codes:

    • ICN (International Code of Nomenclature for algae, fungi, and plants)

    • ICZN (International Code of Zoological Nomenclature)

  • Each organism has a binomial name (Genus + Species).

  • The scientific name is italicized or underlined when handwritten.

  • The first letter of the Genus is capitalized, while the species name is lowercase.

  • Example: Mangifera indica (Mango).

1.2. Binomial Nomenclature (Carl Linnaeus, 1753)

  • Introduced by Carl Linnaeus in Species Plantarum (1753).

  • Rules of Binomial Nomenclature:

    • Latinized names.

    • Priority of names (earliest valid name is used).

    • Name should be unique and universally accepted.

    • Author citation (e.g., Solanum tuberosum L., where "L." denotes Linnaeus).

1.3. Botanical Name vs. Common Name

  • Common Name: Varies by region and language. (e.g., Mango, Aam, Mangue).

  • Botanical Name: Universal and scientific (e.g., Mangifera indica).

2. Classification

Classification is the systematic arrangement of organisms based on similarities, differences, and evolutionary relationships.

2.1. Types of Classification Systems

  1. Artificial System (Based on a few morphological traits)

    • Proposed by Linnaeus (Sexual system of classification).

    • Based on number, arrangement of stamens and pistils.

    • Example: Linnaeus’ classification of plants into 24 classes based on stamens.

  2. Natural System (Based on multiple characteristics)

    • Proposed by Bentham and Hooker (Genera Plantarum, 1862–1883).

    • Considered morphology, anatomy, and physiology.

  3. Phylogenetic System (Based on evolutionary relationships)

    • Proposed by Engler and Prantl (1892).

    • Used evolutionary history, genetics, and fossil records.

2.2. Modern Classification Systems

  • APG System (Angiosperm Phylogeny Group): Based on molecular phylogenetics.

  • Cladistics: Uses shared derived characteristics (cladograms).

  • Molecular Taxonomy: Uses DNA sequencing to classify organisms.

2.3. Major Taxonomic Ranks (Hierarchy of Classification)

  1. Kingdom

  2. Division/Phylum

  3. Class

  4. Order

  5. Family

  6. Genus

  7. Species

Example: Classification of Mango (Mangifera indica):

  • Kingdom: Plantae

  • Division: Angiosperms

  • Class: Dicotyledonae

  • Order: Sapindales

  • Family: Anacardiaceae

  • Genus: Mangifera

  • Species: indica

2.4. Five Kingdom Classification (R.H. Whittaker, 1969)

  1. Monera (Bacteria, Cyanobacteria)

  2. Protista (Algae, Protozoa)

  3. Fungi (Mushrooms, Yeasts)

  4. Plantae (All plants)

  5. Animalia (All animals)

2.5. Three Domain System (Carl Woese, 1990)

  • Archaea (Primitive prokaryotes)

  • Bacteria (Modern prokaryotes)

  • Eukarya (All eukaryotic organisms)


  • .



    • Conclusion

    • Nomenclature follows universal rules to avoid confusion.

    • Classification systems have evolved from artificial to phylogenetic and molecular approaches.

    • Modern classification is based on evolutionary relationships and genetic data