Classification is defined as grouping organisms based on observable similarities and differences
The practice of classifying organisms is referred to as taxonomy. Classification is usually a hierarchical process. One begins with general and broad differences, and then one systematically introduces more and more detailed and specific criteria.
There are two methods of classifying organisms:
Artificial classification systems, such as the grouping of vehicles into those that provide transport on land, water or air, are based on arbitrary groupings of similar features and have little meaning.
The Natural / Biological classification system, however, is based on research in anatomy, physiology, chemistry, genetics and many other branches of science. It is a scientific method of classification that groups organisms that share common features.
This classification is not random, but rather it describes evolutionary relationships. As a consequence, it is always necessarily hierarchical, where the important features inherited from a common ancestor determine the group in which the organisms are placed. For example, humans and whales both feed their young on milk, which is a characteristic inherited from a common ancestor. This similarity places them under the same class, mammals, even though their habitats are completely different.
Each organism is grouped into one of five large groups or kingdoms, which are subdivided into smaller groups called phyla (singular: phylum) and then smaller and smaller groups with other names.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Carolus Linnaeus (Carl Von Linne) (1707–1778) was an 18th century Swedish botanist and physician. He classified plants and animals according to similarities in form and divided living things into two main kingdoms namely — plant and animal kingdoms. He named the plants and animals in Latin or used latinised names in his books Species Plantarum (1753) and Systema Naturae (1758). The two-kingdom classification system devised by Linnaeus is not used today. As scientists discovered more and more about different organisms, they expanded the system to include many more kingdoms and groupings. However, one of Linnaeus more enduring systems was the system of naming organisms- called binomial nomenclature. We will learn more about binomial nomenclature in the next section.
One of Linnaeus' greatest contributions was that he designed a scientific system of naming organisms called binomial nomenclature (bi - 'two', nomial - 'names'). He gave each organism a two part scientific name - genus (plural - 'genera') and species (plural - 'species') names. The genus and species names would be similar to your first name and surname. Genus name is always written with a capital letter whereas species name is written with a small letter. The scientific name must always be either written underlined or printed in italics.Since Latin was once the universal language of science among western scholars in medieval Europe, these names were typically in Latin.
For example the scientific name of the African elephant is Loxodonta africana.
Genus: Loxodonta Species: africana