Invertebrates: Sponges

Invertebrates: Sponges phylum porifera Sponges are best described as aggregations of specialized cells Do not form true tissues Simplest multicellular animals Nearly all are marine All are sessile (permanently attached to substrate)

Invertebrates: Sponges Sponges are suspension feeders (filter feeder) As sponges get larger, they need structural support. Most have spicules, transparent siliceous or calcareous supporting structures of different shapes and sizes. ( Mercedes Benz shape …) Many also have tough elastic fibers made of a protein called spongin

Giant Sponges!!!

Anatomy of a Sponge Outer surface is covered with flat cells called pinacocytes and occasional tube-like pore cells (porocytes) through which a microscopic canal allows water to enter. Water is pumped into a larger feeding chamber line with collar cells (choanocytes) Each choanocyte has a flagellum the creates currents and traps food particles. Water then exits through a large opening on top of the sponge – osculum. Sponges are sexual and asexual reproducers and some are hermaphrodites some are not.

Anatomy of a Sponge

Invertebrates: Sponges Sponges benefit some marine animals by providing a habitat Some sponges are green because they have photosynthetic organisms in their tissues Many sponges protect themselves from predators by producing toxins Some biologists believe sponges evolved independently from all other animals Some sponges live on the seafloor and some on lake bottoms