To evaluate the appropriateness of phylogenetic trees in biological evolution, we expanded a
pre-existing baseline data set of randomly selected organisms by incorporating a collection of intentionally
chosen organisms. Using two different clustering algorithms—Ward’s method and neighbor-joining—we
constructed phylogenetic trees based on nucleotide sequences as well as amino acid composition and nucleotide
content of complete mitochondrial genomes and 16S rRNA and NADH dehydrogenase subunit 5 genes. We
compared classifications derived from cluster analyses with data based on mathematical calculations of complete mitochondrial genomes. Analyses of predicted amino acid composition from complete mitochondrial
genomes and of 16S rRNA sequences clearly differentiated terrestrial and aquatic vertebrates. Although no truly
representative phylogenetic tree exists, phylogenetic trees provide scientifically appropriate information about
biological evolution