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The Living World - Need for classification

Grade 11CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Biodiversity: The number and types of organisms present on Earth, currently estimated to be between 1.7−1.81.7 - 1.8 million species.

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Nomenclature: The process of providing a standardized name to a living organism so that it is known by the same name all over the world.

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Binomial Nomenclature: A naming system proposed by Carolus Linnaeus where each name has two components: the Generic name (Genus) and the specific epithet (Species). Example: Homo sapiens\textit{Homo sapiens}.

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Taxonomy: The branch of science dealing with the identification, nomenclature, and classification of organisms based on external and internal structures, cell structure, and ecological information.

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Systematics: The study of the diversity of organisms and all their comparative and evolutionary relationships (phylogenyphylogeny).

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Rules of Nomenclature: Scientific names are usually in Latin and written in italics. The first word (Genus) starts with a capital letter, while the specific epithet starts with a small letter. When handwritten, they are separately underlined.

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Taxonomic Hierarchy: The framework of classifying organisms in a definite sequence of categories: Kingdom →\rightarrow Phylum (for animals) / Division (for plants) →\rightarrow Class →\rightarrow Order →\rightarrow Family →\rightarrow Genus →\rightarrow Species.

📐Formulae

Scientific Name=Genus+Specific Epithet+(Author’s Name in abbreviated form)\text{Scientific Name} = \text{Genus} + \text{Specific Epithet} + (\text{Author's Name in abbreviated form})

Diversity Range≈1.7×106 to 1.8×106 species\text{Diversity Range} \approx 1.7 \times 10^6 \text{ to } 1.8 \times 10^6 \text{ species}

💡Examples

Problem 1:

Correctly identify the scientific name for Mango according to Binomial Nomenclature rules and explain its parts.

Solution:

Mangifera indica\textit{Mangifera indica} L.

Explanation:

In the name Mangifera indica\textit{Mangifera indica} L., Mangifera\textit{Mangifera} represents the Genus (Generic name), indica\textit{indica} represents the specific epithet (Species), and 'L.' is the abbreviation for Linnaeus, the author who first described the species.

Problem 2:

Arrange the following taxonomic categories in descending order: Family, Species, Class, Kingdom, Order, Phylum, Genus.

Solution:

Kingdom →\rightarrow Phylum →\rightarrow Class →\rightarrow Order →\rightarrow Family →\rightarrow Genus →\rightarrow Species

Explanation:

This represents the taxonomic hierarchy where 'Kingdom' is the highest (most general) rank and 'Species' is the lowest (most specific) rank.

Need for classification - Revision Notes & Key Diagrams | CBSE Class 11 Biology