Portal:Animals/Theme
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Phylum
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In biology, a phylum is a taxonomic rank below Kingdom and above Class. "Phylum" is equivalent to the botanical term division. The kingdom Animalia contains approximately forty phyla; the kingdom Plantae contains twelve divisions. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta. The best known animal phyla are the Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata, the phylum to which humans belong, along with all other vertebrate species. Although there are 36 animal phyla, these nine include over 96% of animal species. Many phyla are exclusively marine, and only one phylum, the Onychophora (velvet worms) is entirely absent from the world's oceans—although ancestral onycophorans were marine.