How organisms in the Animal Kingdom are classified?
Zoologists, who study animals, estimate that there are over four million animal species live on earth. All these animals are divided into 35 or more phyla according to their body plan, similarities and evolutionary relationships. Zoologists divide all these animals into two major subphyla. Subphylum Invertebrata (invertebrates) animals with no bones. All invertebrates make up more than 95% of all animal species. The vast majority of invertebrates are insects, snails, jellyfish, and worms. Subphylum Vertebrata (vertebrates) animals with back bones. Vertebrates such as fish, frogs, snakes, birds, and mammals make up less than 5% of all animals on earth. The classification hierarchy today is recognized from the least inclusive to the most inclusive or vise versa as the following: species grouped into genera (genus – singular), genera into families, families into orders, orders into classes, classes into phyla (phylum – singular), phyla into kingdoms, kingdoms into domains (domain = a taxo
