In Biology, what is a Phylum?
In biology, a phylum is a division of organism (taxonomic rank) below kingdom (such as Animalia) and above class (such as Mammalia). There are 38 animal phyla, with nine phyla — Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata — making up the vast majority of all animals. The phyla Arthropoda (arthropods) and Nematoda (nematodes) are the most successful, with the former containing between 1 and 10 million species, and the latter containing between 80,000 and 1 million species. Animal phyla are broadly classified into two groups: deuterostomes and protostomes, distinguished from differences in embryonic development. Only three new animal phyla have been discovered in the last century, although over ten animals formerly put under other phyla have been recognized as their own phyla. Different phyla have fundamental differences in their body plans, and each make up a monophyletic group, meaning the phylum consists of all the descend
