article: Evolutionary grade
links: Labyrinthodont Synapsid Phylogenetics Paraphyly Coleoidea Vascular tissue Ammonoidea Bryophyte Poikilotherm Fish Nautiloid Dinosaurs Agnatha Polyphyly Julian Huxley Marchantiophyta Physiology Cladistics Vascular plant Chondrichthyes Osteichthyes Ernst Mayr Wastebasket taxon