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 cellsChoanocyte = collar cellSpongocoel = central cavityMesohyl = 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 CO2 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