parafiléticos

Parafileticos is a term used in biology, specifically in cladistics and phylogenetics, to describe a group that contains an ancestor but not all of its descendants. In simpler terms, a parafiletic group is an unnatural grouping because it excludes some members that would logically belong with the shared ancestor. This type of grouping is contrasted with monophyletic groups, which include an ancestor and all of its descendants, and polyphyletic groups, which consist of unrelated organisms that share similar traits due to convergent evolution.

The concept of parafiletic groups is important in understanding evolutionary relationships. Historically, many classification systems were based on parafiletic groups, leading to classifications that did not accurately reflect evolutionary history. For example, traditionally, reptiles were considered a group, but this group is parafiletic because it excludes birds, which evolved from reptilian ancestors. Modern phylogenetic classifications aim to create only monophyletic groups, which are considered to be more evolutionarily accurate. Identifying and rectifying parafiletic groupings is a key objective in constructing modern phylogenetic trees and understanding the branching patterns of life.