Classification of Living Organisms

Classification is the process of organising living organisms into groups based on shared characteristics. It helps biologists make sense of the enormous diversity of life on Earth. In this lesson we cover the Linnaean system, taxonomic levels and the five kingdoms.

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Why Classify?

With an estimated 8.7 million species on Earth, classification allows scientists to:

• Organise the vast diversity of life into manageable groups
• Identify organisms accurately and consistently worldwide
• Understand evolutionary relationships between organisms
• Predict characteristics of organisms based on their group
• Communicate about organisms without confusion (using scientific names)

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Carl Linnaeus (1707–1778)

The modern classification system was developed by the Swedish botanist Carl Linnaeus (also known as Carolus Linnaeus). His system has two key features:

1. Hierarchical Classification

Organisms are placed into a series of groups within groups (a hierarchy). Each level in the hierarchy is called a taxon (plural: taxa).

2. Binomial Nomenclature