Phylum Porifera Sponges are the simplest of all animals; best described as aggregations of specialized cells Sponges do not have true tissues or organs; cells are largely independent of one another All are sessile (non-mobile) Porifera means “pore bearer” NO body symmetry

Phylum Porifera Tiny pores, or ostia allow water to enter and circulate through a series of canals where plankton and other organic debris are filtered out and eaten Sponges are suspension feeders, animals that eat food particles suspended in the water column Filter feeders; they actively filter out food particles

Phylum Porifera Water is pumped into a feeding chamber lined with collar cells, or choanocytes Choanocytes have a flagella that generates a current, and a thin collar that traps food particles Food is then ingested within the cell

Phylum Porifera As sponges get larger, they need structural support Most have spicules, supporting structures of different shapes and sizes, made of silica or calcium carbonate Many also have a ‘skeleton’ of tough, elastic fibers made of a protein called spongin

Phylum Porifera Wandering cells, or amebocytes secrete the spicules and spongin Amebocytes also transport and store excess food particles, and can change into other cell types, quickly ‘repairing’ any damage to the sponge ~80% of food particles are engulfed and ingested by choanocytes; smaller particles, inc. bacteria and dinoflagellates are eaten by amebocytes

You are what you eat… The silica frustules of diatoms and other phytoplankton help make the glass spicules of sponges! Diatoms Sponge

Sponges are boring! A family of sponges known as boring sponges bore into shells by use of an enzyme produced by the amebocytes Sponge larvae settle onto wood and/or shells and create burrows where they will grow

Sponge worthy? Unlike most animals, many sponges reproduce asexually Branches or buds break off to form separate, but identical, sponges Like all animals, however, sponges also reproduce sexually Specialized coanocytes or amebocytes produce eggs and sperm Sponge larvae is planktonic!