The three domains system is a modernized version of the Carl Linnaeus system. This system divides all living organisms into three groups: Archaea, Bacteria, and Eukaryote. Discovered by Carl Woese in 1977, this system can also be used to demonstrate the similarities between the six kingdoms. Animals, Plants and Fungi all fit in the Eukaryota group, since they share similarities, while Bacteria and Archaea make up their own separate groups. Other groups are also classified within the three domains. The diagram below illustrates how the three domain system splits up.