In biology, a clade is a group of organisms that includes a common ancestor and all its descendants. Clades are a key concept in cladistics, a modern taxonomy approach used across biological fields. They can represent an individual, population, or species (extinct or extant) and are nested within one another, reflecting evolutionary history as populations diverge.
Recently, cladistics has transformed biological classification and uncovered unexpected evolutionary relationships, such as fungi being more closely related to animals than to plants, and archaea being distinct from bacteria. Taxonomists increasingly strive to name only monophyletic groups, or true clades.
