How many kingdoms are traditionally recognized in biological classification?

Traditionally, biological classification recognizes six kingdoms. This system divides life into the categories of Archaea, Bacteria, Protista, Fungi, Plantae, and Animalia. Each kingdom represents a fundamental way in which organisms are organized based on characteristics such as cell type, complexity, and modes of nutrition.

The five-kingdom system, which includes Monera (encompassing bacteria and archaea), is simpler and more outdated since it combines two distinct groups into one, despite their significant differences. As scientific knowledge has evolved, so has the classification system, leading to the more comprehensive six-kingdom model.

More recently, an even more granular classification has emerged, with a push toward using domains alongside kingdoms, which can lead to discussions of more than six classifications, but traditionally, six kingdoms remain the widely accepted approach within the context of standard biological classification.