1. Phylum Porifera

2. Kingdom Animalia (animals)
Phylum Porifera (sponges)
Classes: Calcarea (calcerous sponges - having spicules),
Demospongiae (horn sponges, like the bath sponge),
Scleropongiae (coralline or tropical reef sponges), and
Hexactinellida (glass sponges).

3. Sponges
A. Most primitive of all multicellular animals
B. Adults are sessile
C. Porifera
1. means “pore-bearing”
2. tiny pores used to food from the
water
2. Why classified as animals and not plants?
A. 2 reasons
1. sponge cells lack cell walls
2. sponges are heterotrophic

4. B. Differences between sponges and other animals
1. sponge cells are not organized into
recognizable organs
2. believed to have evolved separately from
other animals
3. Sponge structure
A. Sponges use different types of cells for different purposes
1. collar cells
a. whip like flagella that beat water
through the body wall into the
central cavity

5. b. also snag food particles from water
2. amebocytes
a. wandering cells
b. digest and distribute food
c. produce components of the sponge
skeleton
3. spicules
a. crystal like spikes support its body
b. made of CaCO3 or SiO2
c. can interlock for rigid network
4. spongin
a. protein which also supports the body
b. soft, flexible, elastic = “spongy”

7. 4. Reproduction
A. Sexual
1. produce sperm and eggs
2. released into the water and hope it finds
its way to another sponge
3. if sperm and egg meet it is free
swimming until it lands then becomes
sessile
B. Asexual
1. budding – piece of sponge falls off and
grows into a new sponge