In phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but doesn't contain all the descendants of that ancestor. Relation to monophyletic groups Groups that do include all the descendants of the most recent common ancestor are said to be monophyletic. A paraphyletic group is a monophyletic group from which one or more of the clades is excluded to form a separate group (as in the paradigmatic example of reptiles and birds, shown… (More on Paraphyly)