Porifera, Cnidaria Sponges of phylum Porifera and jellyfish of phylum Cnidaria are multicellular heterotrophs and members of kingdom Animalia. Their bodies and body cavities are simple and they lack the complex behavior and sensory capabilities of most higher animals. However, their diversity and persistence through time demonstrate the elegance and efficiency of their simple design. Phylum Porifera Sponges are the simplest of the major animal phyla and comprise 10,000 species. Most sponges live in the ocean, but a few encrust rocks and sticks in freshwater.
Sponges lack tissues and organs and are typically asymmetrical assemblages of cells.
Bodies of asymmetrical organisms have no symmetry or pattern such as left and right halves or anterior and posterior regions. Sponge cells are so loosely assembled that if a sponge is forced through a fine mesh, the disassociated cells will survive. Even more remarkably, the disassociated cells will survive. Even more remarkably, the disassociated cells can reassemble as a functioning organism. Structure of Sponges Sponge walls filter seawater and remove food particles.