1. The Living World

Characteristics of living organisms

 Growth

 Reproduction

 Metabolism

 Cellular organization

 Consciousness

 

Diversity

 The number and types of living organisms present on earth is known as biodiversity.

 Total known and described species are between 1.7-1.8 million.

 

Nomenclature

 The process to standardise the naming of a living organism is known as nomenclature.

 The process of assigning a pre-existing individual or class name to an individual organism is identification.

 The system of providing a name with two components (Generic name and specific epithet) is known as Binomial nomenclature.

 

(An epithet is a word in the scientific name of an organism, following the name of the genus)

 Binomial nomenclature was given by Carolus Linnaeus.

 The biological names are generally in Latin and written in italics (underlined when written by hand). Example: The biological name of mango is Mangifera indica.

 The first word in a biological name (e.g. Mangifera) represents generic name, which always starts with capital letter while the second component (e.g. indica) represents the specific epithet that starts with a small letter.

 IUBN – International Code of Botanical Nomenclature and IUZN – International Code of Zoological Nomenclature are responsible for approving a name and ensuring that the name has not been given to any other plant or animal respectively.

 

Classification

 It is the scientific ordering of organisms in a hierarchical series on the basis of its relationships.

 

 

 It is done after finding the correct name and proper position of an organism in a hierarchy.

 Taxon is the scientific term for these categories. It is referred to as the unit of classification. This process of classification is known as taxonomy.

 Taxonomy is the branch of biology that deals with identification, naming, and classification of organisms.

 The hierarchical arrangement of various taxonomical categories in descending order is: Kingdom → Phylum (Division)  Class  Order  Family → Genus →Species. All these categories together form a taxonomic hierarchy.

 

Aid to memory - You can learn this hierarchy using the following mnemonic: Kids Prefer Cheese Over Fried Green Spinach

Ø Kingdom - It is the highest level of classification. Example: Kingdom Plantae includes all plants and kingdom Animalia includes all animals.

Ø Phylum - It is the second highest level of classification. It is comprised of group of related classes. Example: Kingdom Animalia includes phylum Porifera, Coelenterata, Chordata, etc. Term division is used in case of plants.

Ø Class - A phylum/division is divided into many classes. Class is a lower taxonomical category than phylum comprising related orders. Example: Phylum Arthropoda includes class Insecta.

Ø Order - A class is divided into many orders. It is a taxonomical category comprised of related families. For example: Class Insecta includes order Diptera.

Ø Family - Family includes many genera with less number of similarities. An order divides to form many families. For example, the family Felidae includes individuals of genus Panthera and Felis.

Ø Genus - Genus comprises a group of related species having many similar characters. For example, lion and tiger are placed under the genus Panthera.

Ø Species - It is the basic level of classification. It is defined as a group of organisms that is capable of inter-breeding to produce fertile offspring.

 

Taxonomical aids

 These are the procedures and techniques used to store and preserve information as well as specimens of various plants and animals.

 These help in identification, naming, and classification of organisms.

 Herbarium

 

 

Ø It is the storehouse of collected plant specimens.

Ø Collected plant specimens are dried, pressed, and preserved on sheets and then arranged systematically according to the universally accepted system of classification.

Ø Herbarium sheet contains label regarding date, place of the collection, scientific name, family, collector’s name, etc. of the specimen.

 Botanical gardens

Ø It has the collection of living plant species that are grown for identification and reference.

Ø Each plant contains labels indicating their scientific name and family.

Ø Some famous botanical gardens are Indian Botanical Garden, Calcutta (largest in India), Royal Botanical Garden, Kew (largest in world till date), and National Botanical Research Institute.

 Museum

Ø It is the repository that has a collection of various plant and animal specimens that are preserved for study and reference.

Ø The organisms are preserved either in preservative solution or in the form of dry specimens.

Ø It often has a collection of skeletons of animals also.

 Zoological parks

Ø Wild animals are kept in protected environments.

Ø Provides opportunity for studying the behaviour and food habits of the animals

 Key

Ø Keys are used for identification of plants and animals based on similarities and dissimilarities.

Ø Manuals, monographs, and catalogues are other means of recording descriptions.

Ø Manuals help in the identification of names of various species of organisms in a given area.

Ø Monograph is a detailed and well-documented work on any particular taxon.