nonmonofülogeneetiline

Nonmonofülogeneetiline refers to a taxonomic group that does not include all of the descendants of a single common ancestor. In evolutionary biology, a monophyletic group, also known as a clade, is defined as a group that consists of a common ancestor and all of its descendants. If a group excludes one or more descendants of that common ancestor, it is considered nonmonophyletic.

There are two types of nonmonophyletic groups. A paraphyletic group includes a common ancestor and some, but not all, of its descendants. A polyphyletic group is a group whose members' last common ancestor is not a member of the group. This often arises from convergent evolution where organisms share similar traits due to similar environmental pressures rather than shared ancestry.

Taxonomic classifications aim to reflect evolutionary history, and therefore, ideally, all recognized taxa should be monophyletic. The identification of nonmonophyletic groups can be a result of historical classification based on superficial similarities or incomplete knowledge of evolutionary relationships. Modern phylogenetic methods, such as molecular data analysis, are crucial for identifying and correcting nonmonophyletic groupings, leading to a more accurate representation of the tree of life. Recognizing and revising nonmonophyletic groups is a continuous process in the field of systematics.