Swedish naturalist Carolus Linnaeus divided the animal world into 3 groups. Primates, Secundates and Tertiates Tertiates are divided into 5 classes. Vermis, Insecta, Pisces, Amphibia and Avis.
Hickman et al. (2017) in the book Integrated Principles of Zoology divides the animal kingdom into two phases. Main phase and secondary phase.Dr. Siddique Publications
1. Major phyla: Those groups with more than 5000 species are called major phyla. There are 9 main episodes in total. Among the major episodes, 8 are non-chordata and 1 is chordata. The main groups are Porifera, Cnidaria, Platyhelminthes, Nematoda, Mollusca, Annelida, Arthropoda, Echinodermata and Chordata.
2. Minor phyla: The number of species in the group is less than 5000 is called minor phyla. If secondary phase- Placozoa, Ctenophora