Scientific classification refers to the way biologists separate both extinct and living species into categories. Modern classification is connected to the system of Carolus Linnaeus. Linnaeus grouped organisms depending on shared physical characteristics. However, organisms were not always classified using the system of Carolus Linnaeus. Discovered by Aristotle (384-322 BC), a system was used that classified organisms by the way that they transported, which was either by air, land, or water. This was the earliest known system of classification. The Carolus Linnaeus system would come later on. It began with Ibn Rushd, a judge. He translated and shortened Aristotle’s book "de Anima” . After this, came the recognition of cells in organisms recognized by Jan Swammerdam, a Dutch naturalist and microscopist. Then, John Ray, an English naturalist, created classification of plants in “Historia Plantarum” , which was a big, major step towards modern classification. All of these events lead up to the discovery of modern classification, discovered by Carolus Linnaeus.There are seven groups that organisms are placed into using the Carolus Linnaeus system. The seven groups are Kingdom, Phylum, Class, Order, Family, Genus, and Species.