Taxonomies are continually changing. Labyrinthodontia, which remains a common term in the literature, has nonetheless fallen out of favor with many scientists in recent classifications because it is paraphyletic—that is, the group does not include all the descendants of the most recent common ancestor. Today, biological classification is not so concerned about similar morphological features but rather the ancestral-descendant relationships of taxonomic groups. This not only shows the changing nature of science—what a few years ago may be one taxonomy for amphibians today would be different—but also shows the importance of ascertaining relatedness of organisms. Just as human societies place importance on relatedness and lineage, i.e. family trees, so is the current emphasis in biological classification.