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Introduction to Biological Classification

Author(s): Deanne Erdmann, MS

Hierarchical Classification

Carolus von Linnaeus created a hierarchical classification system using seven taxonomic categories, or taxa (Kingdom, Phylum, Class, Order, Family, Genus, Species). These categories are based on shared physical characteristics, or phenotypes, within each group. Beginning with kingdom, each successive level of classification becomes more and more specific. Organisms within the same order have more in common with one another than organisms within the same class. For example, all species of bears are mammals, but not all mammals are bears. A useful pneumonic tool to help students remember the hierarchical classification system is: King Phillip Came Over For Green Soup, with the first letter of each word representing each category, beginning with kingdom and ending with species.