Classification

• Classification is the organising of all living organisms into groups based on their common attributes and relations.

• It was Carl Linnaeus who first introduced the current system of classification, believed to be more systematic and easy to understand.

• The Hierarchy of classification includes - Kingdom, Phylum, Class, Order, Family, Genus and Species. Mnemonic to remember is “King Phillip Came Over For Good Soup”.

• The five kingdoms used in classification are – Monera, Protista, Fungi, Plantae and Animalia.

• Monera includes all unicellular organisms which do not have a well-delineated nucleus, like bacteria.

• Protista comprises unicellular plants and animals which have a well-delineated nucleus.

• Fungi include both unicellular and multicellular organisms and mostly feed on dead remains of plants and animals.

• Plantae consists of all green plants that can synthesise food through photosynthesis.

• Animalia includes beings that are multicellular, and they cannot make their own food.

• Binomial Nomenclature is the system for naming species. The first part of the name denotes the genus, and the second part refers to the species.

• Binomial names are often derived from Latin and are written in italics.

• Some organisms are difficult to classify and have characteristics that belong to more than one group. These organisms are often referred to as ‘problematic organisms’.

• Evolution often results in changes in classification because new evidence may show that some organisms are related in ways that were not previously realised.

• The process of natural selection is a crucial factor influencing classification, as species with similar traits and characteristics indicate common ancestry and thus belong to the same group.

• Classification is not fixed and evolves as new discoveries and technologies become available, further helping in the understanding of relationships between different organisms.

• Molecular biology, in particular DNA and protein analysis, is increasingly used to help determine evolutionary relationships and thus aid the process of classification.

• Natural selection and the resulting evolution have an ongoing influence on classification as new species evolve and others become extinct.