Test analysis: the classification of organisms from big to small is: boundary, phylum, class, order, family, genus and species. The smaller the classification, the closer the genetic relationship of organisms, the more the same * * * features, the greater the classification, the farther the genetic relationship, and the less the same * * * features. Frogs belong to amphibians, locusts belong to arthropods, sharks belong to fish and sheep belong to mammals.