How Are Organisms Classified?

In terms of biological classification, organisms are classified, or grouped, with other organisms that they are most closely related to. These small groups are then classified together into larger groups and so on, until we reach the top level of classification which places organisms in one of three biological domains - Archaea, Bacteria and Eukarya. When each organism is classified in this way it allows scientists to see the relationships between different species, and make sense of the hugely diverse array of life.