We compared 753 genomes of bacteria, archaea, and mitochondria (more than 540 M data) and found four unique ultraconserved sequences in 352 vertebrate mitochondrial genomes which are the longest or second longest or third longest ultraconserved subsequences in the vertebrate mitochondrial genomes, their lengths are approximate to those of small RNA. Surprisingly, the classification and evolution relationship among some high-level categories of animals can be clearly reflected by their regularity of occurrence; moreover, these findings gave rise to some new ideas of evolution of mitochondria and living beings. For instance, the variations in mitochondrial genomes of animals may help clarify the evolution relationship between Aves and Reptile, and understand the fact that the origin of mitochondrion is at least not a simple copy of genomes of lower living things such as bacteria and archaea.