CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search For other uses, see Clade (disambiguation) . Cladogram (family tree) of a "large" biological group, showing the last common ancestor of the composite tree, which is the vertical line 'trunk' at the bottom. The blue and red subgroups (at left and right) represent clades, or monophyletic (that is, complete) taxonomic groups; each shows its common ancestor 'branch', or 'stem', and all descendant branches. The green subgroup is not a clade; it represents a paraphyletic group, which is incomplete because here the blue branch, although descended with it from a common ancestor stem, is excluded from the green subgroup. A clade (from Ancient Greek : κλάδος , klados , "branch") is a group of organisms that consists of a common ancestor and all its lineal descendants , and represents a single ...