Invertebrates Sponges Invertebrates Sponges phylum porifera Sponges are

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