Characteristics of living organisms
* Living organisms display certain characteristics.
* Growth and reproduction are the non-definitive characteristics of living organisms.
* Metabolism and cellular organisation are considered to be the definitive characteristics of living organisms.
* Living organisms, whether unicellular or multi-cellular, grow due to cell division.
* Both unicellular and multi-cellular organisms reproduce.
* Reproduction, however, is not a definitive criterion for distinguishing the living, because some organisms like mules and sterile worker cannot produce offspring.
* All living organisms sense and respond to environmental stimuli such as light, water and temperature.
* Consciousness is therefore, another definitive characteristic of living beings.
Classification of Living Organisms
* The earth abounds with millions of different types of fungi, plants, microorganisms and animals.
* Species is a group of similar individuals, sharing a common gene pool, and interbreeding freely, producing fertile progeny.
* The number and type of organisms on the earth is referred to as biodiversity.
* Scientific names have two components, the generic name and the specific epithet.
* The system of representing a name with two components is called Binomial nomenclature, and was devised by Carolus Linnaeus.
* The scientific term given for different categories of organisms is called taxa.
* The process of classifying living organisms into different taxa based on their characteristics is called taxonomy.
* The study of the different types of organisms and the relationships among them is known as systematic.
Taxonomic Categories
* Taxonomists have classified living organisms in a hierarchical structure, which consists of ranks or categories.
* Organisms are classified using common categories such as kingdom, phylum or division, class, order, family, genus and species.
* The taxonomic categories from species to kingdom are known as the broad categories.
* As we go higher from species to kingdom, the number of common characteristic features goes on decreasing.
Taxonomic Aids
* The classification of living organisms into different categories based on their characteristics is called taxonomy.
* Taxonomic studies help in disciplines such as forestry, industry, agriculture, and in knowing the biodiversity.
* Herbarium, botanical gardens, biological museums, zoological parks, key, flora, manuals and monographs are examples of taxonomical aids.
* Taxonomical aids play a crucial role in studying the important facets of living organisms and saving important information about them for future reference.
