The arrangement of various taxa in hierarchical order is called taxonomic hierarchy. The hierarchy indicates the various levels of kinship. The number of similar characters of categories decreases from lowest rank to highest rank. The hierarchical system of classification was introduced by Linnaeus.
The hierarchy of major categories is:
Species —Genus►Family —► Order—► Class
Kingdom -4— Phylum or Division
Increasing specificity – ► Decreasing specificity

Classification of a plant (Wheat):
Kingdom  –  Plantae
Division   –  Angiospermae
Class         –  Monocotyledonae
Order        –  Poales
Family      –  Poaceae
Genus       – Triticum
Species     –  Aestivum
Classification of an animal (Housefly):
Kingdom  –   Animalia
Phylum    –   Chordata
Class        –   Insecta
Order       –   Diptera
Family     –  Muscidae
Genus      –   Musca
Species    –   Domestica