Traditional taxonomy uses a hierarchical classification
where organisms are placed into progressively more restricted groups (taxa).
Starting from the most comprehensive taxon, Linnaeus classified organisms into kingdom, phylum, class, order, family, genus, and species.
Leopards and humans belong to kingdom Animalia, phylum Chordata, class Mammalia.
While leopards are in order Carnivora, humans are in order Primates.
A taxon above kingdom called domain was added after Linnaeus proposed these 7 levels.