parifüleetilised

Parifüleetilised refers to a concept in cladistics, the study of evolutionary relationships among biological entities. Specifically, it describes a group of organisms that are related by having a common ancestor, but the group does not include *all* of the descendants of that ancestor. This means that a parifüleetiline group is not a true clade, which by definition must be monophyletic and therefore include the common ancestor and all of its descendants.

In simpler terms, a parifüleetiline group is like a family tree where you include your grandparents and parents, but exclude some of your aunts, uncles, or cousins who also descend from those grandparents. The excluded relatives are the reason the group is parifüleetiline, rather than monophyletic.

An example often cited is the traditional classification of reptiles. While dinosaurs and birds share a common ancestor, birds are typically classified separately. If reptiles were considered a parifüleetiline group, it would include the common ancestor of all reptiles and some of its descendants, but not all of them (specifically excluding birds). This contrasts with a monophyletic group, which would include the common ancestor and every single lineage that descended from it. Understanding the distinction between monophyletic and parifüleetiline groups is crucial for accurate phylogenetic reconstruction and understanding the evolutionary history of life.