About the PhylumPorifera, a phylum within the Kingdom Animalia, consists of all species of sponges, about 5,000 total. Sponges are among the simplest animals on the planet, and it is believed that they evolved from the first multi-cellular organisms which eventually evolved into animals. The phylum Porifera represents the only phylum of the Parazoa branch of Kingdom Animalia--those without true tissues, that diverged from the lineage shortly after the evolution of multicellularism from colonial protists
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Characteristics1)No definite symmetry.
2)Body multicellular, few tissues, no organs. 3)Cells and tissues surround a water filled space but there is no true body cavity. 4)All are sessile, (live attached to something as an adult). 5)Reproduce sexually or asexually, sexual reproduction can be either gonochoristic or hermaphroditic. 6)Has no nervous system. 7)Has a distinct larval stage which is planktonic. 8)Lives in aquatic environments, mostly marine. 9)All are filter feeders. 10)Often have a skeleton of spicules |