classification of invertebrates on basis of major and minor phyla

These phylum were later classified as Major and Minor Phyla on the basis of their number of species and their ecological importance. According to first condition there are only 11 phyla. They are Porifera, coelenterata, Platyhelminthes, Rotifera, Nematoda, Mollusca, Annelida, Arthropoda, Ectoprocta and Echinodermata. These are called Major phyla and remaining 19 are called Minor phyla. Again according to the second condition among these 11 phyla only among 9 are included in new classification. The nine phyla which are included are Porifera, coelenterata, Platyhelminthes, Nematoda, Mollusca, Annelida, Arthropoda, Echinodermata. The two phyla are removed because they do not play any role in ecological communities.