Parafüleetilisest

Parafüleetilisest refers to a type of phylogenetic classification that includes a common ancestor but excludes one or more of its descendants. In evolutionary biology, a monophyletic group, also known as a clade, consists of a common ancestor and all of its descendants. A paraphyletic group, on the other hand, does not include all of the descendants of the common ancestor. This means that while the group shares a common ancestor, some of its evolutionary relatives are placed outside of it.

An example often cited to illustrate a paraphyletic group is the traditional classification of "reptiles." If one considers the most recent common ancestor of all reptiles (including birds), a paraphyletic group would include lizards, snakes, turtles, and crocodiles, but exclude birds, even though birds evolved from within the reptilian lineage. Modern phylogenetic classification aims to create monophyletic groups. The recognition of paraphyletic groups can arise from historical classification systems that were not based on complete evolutionary relationships. Understanding the distinction between monophyletic and paraphyletic groups is crucial for accurate phylogenetic analysis and constructing evolutionary trees.