The Great Barrier Reef Library

A comprehensive guide to The Great Barrier Reef

Tree of Life

Tree of Life

By on November 10, 2017

Tree of Life

Use The Tree of Life  to find any animal or group of animals that you would like to know more about.  Simply work your way through the links until you find what you are looking for.  If you already know what you are looking for, then try our search function in the menu bar.  Note that we are consistently adding information to this page and its links.


The definition of life on Earth follows a simple set of rules. A living organism needs to have a way to maintain its internal environment and contain its molecules within a cell/s. They must also metabolise and grow, respond to their environment, reproduce and evolve. The system below (Linnaeus System) groups together living entities with others that share similar characteristics:

Domain – Kingdom – Phylum – Class – Order – Family – Genus – Species

Further sub-groups are often used to break down this system further, however we will stick to the above for simplicity.  There is also another entirely different way of grouping organisms, called The Phylogenetics System, which uses DNA and evolution to group organisms.  Whilst this system may be referenced at times, we will stick to the Linnaeus System, grouping animals by characteristics. All organisms are given one or more common names to identify them, however it is important to note that these can vary depending on where you are in the world. Therefore, we will refer to genus and species names to correctly identify each species. When using a scientific name, that standard way of writing it is in italics, with a capital letter for the genus name and a small letter for the species name E.g. Amphiprion percula (True Clown Fish).


This is the highest level of organism classification and has three distinct groups: