1. 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

2. 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

3. 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

4. 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

5. 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

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

8. 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

9. 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!