Characters of Living Organisms

Characteristic Features of Living Organisms

Nutrition: Living organisms take in materials from their environment for growth and other biological activities. They may be autotrophic (self-nourishing) or heterotrophic (depend on other organisms for nutrition).
Respiration: Organisms break down substances to provide energy for life functions. This involves an intricate physiological process in cells called respiration.
Growth: This indicates an increase in size or mass and involves cell division, cell enlargement or both.
Excretion: Living entities get rid of waste products from the body during metabolism. This vital physiological function helps to maintain homeostasis.
Sensitivity: Organisms detect changes in their surroundings and respond appropriately. This change in reaction or response is called sensitivity or responsiveness.
Reproduction: Organisms produce offspring of the same kind. This feature is crucial for species continuity. There are two types, asexual and sexual reproduction.
Movement: Organisms move either entirely or possessing parts that move. This action can be voluntary or involuntary.

Classification of Living Organisms

Kingdom: Organisms are broadly classified into five kingdoms - Monera, Protista, Fungi, Plantae, and Animalia.
Phylum: Each kingdom is divided into smaller groups called phyla (plural of phylum). There are different phyla within each kingdom.
Class: Each phylum is divided into classes. For instance, the phylum Chordata is divided into classes such as Mammalia, Aves, and Reptilia.
Order: Each class is further subdivided into orders.
Family: Orders are divided into families.
Genus: Each family holds several related genera (plural of genus). Genus represents closely related species.
Species: The most specific level of classification. Species are organisms that share common attributes and are capable of interbreeding to produce fertile offspring.

Binomial Nomenclature

The scientific naming of organisms uses a bi-nominal system - Genus and Species. It is the formal system of naming species whereby each species is indicated by two words in Latin.
The genus name is always capitalized, while the species designation is not and both are italicised.
This method of naming was developed by Carolus Linnaeus and is known as binomial nomenclature.