Phylum Porifera- Sponges

 Among the most ancient animals  Mostly marine but some fresh water  Porifera- literally means “pore bearer”, which is appropriate because they have tiny openings all over their body  Once thought to be plants because they are sessile

What are Sponges?  Multicellular, heterotrophic animals  They are very different from other animals  Scientist believe that the evolutionary line that lead to sponges is a dead end and produced no other animals

Phylum Porifera – Internal Structures Porocytes = pore cells Choanocyte = collar cell Spongocoel = central cavity Mesohyl = jelly-like inner layer

1. Body Symmetry  Asymetrical (no symmetry)

2. Level of body organization  Cellular- assemblage of specialized cells  No tissues  No organs

3. Body Cavities/ Coeloms  Nothing that resembles a mouth or gut

Feeding  Filter feeders – microscopic particles stick to collar cells and engulfed by endocytosis  Then passed on to amebocytes where it is digested and moved on to other parts of the cell

Respiration  Water that flows through the sponge allows it to absorb oxygen and release CO 2 into the water

Internal Transport  Mostly done by the water that is filtered through sponges  Amebocytes

Excretion  Metabolic waste is also carried away by the water that is moved through the sponge

Response  No nerve system  Do not respond to stimuli

Movement  Sessile  Attached to the substrate

Reproduction  Reproduce asexually and sexually  Formation of gemmules

Asexual  Reproduce by budding (really it is fragmentation) - part of the sponge simply falls off the parent and grows into a new sponge

Gemmule Formation  When faced with cold winters gemmules are formed  Sphere shaped collections of amebocytes surrounded by a tough layer of spicules that can survive cold temperatures and drought  Reform into a sponge when conditions are favourable

Sexual  Sperm are released into the water via the osculum  Amebocytes collect the incoming sperm and deliver it to the eggs in the body wall  Creates a zygote  Develops into a larvae that swims and is carried away by water  Later settle down and create a new sponge

Boring Sponges  Clean up the ocean floor

Symbiotic relationships  Blue-green algae  Plant like protists  Provide oxygen to the sponge and clean up waste

Human Use  Cleaned dried sponges can be used for bathing  A compound in a Caribbean sponge may be useful against leukemia and the herpes virus  May be the answer to powerful antibiotics  Can possibly fight against certain forms of arthritis