Phenetic versus Cladistic classification of Birds

    Given the phylogeny at top left, a phenetic classification scheme (above, middle) will emphasize the perceived dissimilarity of birds from scaly tetrapods, whereas a cladistic scheme (above, right) will emphasize the more recent common ancestry of birds with crocodiles.

    Modern phylogenetic classifications emphasize character analyses, which show that birds evolved from dinosaurs. That is, perceptions of bird distinctiveness from dinosaurs have changed. Popular discussions, as in "Jurassic Park", present this change in perception as showing that "dinosaurs are more similar to birds." That is, perceptions of dinosaur "primitiveness" have changed. This "neo-phenetic" analysis (below) produces the phylogenetic pattern from phenetic criteria.

    A note on terminology: systematists favoring phenetic and cladistic approaches both claim to be doing phylogenetic taxonomy. The latter term is now more closely associated with cladistic taxonomy, whereas phenetics remains associated with 'traditional taxonomy'.