Porifera, meaning pore bearer, is a phylum which is largely made up from sponges. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them. Sponges have unspecialized cells that can transform into other types. Sponges do not have digestive system. Instead, they rely on maintaining a constant water flow through their bodies to obtain food and to remove wastes. This applies to all sponges. The four classes of this phylum are:
- Calcarea
- Hexactinellida
- Demospongiae
- Homoscleromorpha