Porifera: Sponges
Kingdom: Animal
Phylum: Porifera (pore bearer)
Class: Calcispongiae
Class: Hexdtactinellida
Class: Demospongiae
General Characteristics
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Simplest animal, has organized cells
Put sponge through a sieve, cells would reform the sponge (few weeks)
No head or anterior end, no mouth or gut cavity
5000 species, some in water 8500 ft deep
Habitat
Most live in ocean, very few freshwater
Adults sessile (do not move on own), larvae are freeswimming
______________________: filters small particles of food from water as it passes by or
through some part of the organism
Digestion
Water comes in through pores (flagella beat the water in) and out through top
Small organisms trapped in spaces and digested
Body Structure
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All have central cavity (spongocoele)
All have pores that open from the outside, pass through body wall and open in to
the spongocoele
All have a larger opening on the top (osculum)
Body wall consists of two layers of cells with a jelly-like middle layer (mesoglia)
o Skeleton is in the mesoglia and consists of spicules
o Spiculues are calcium carbonate, silicon oxide fibers, and/or a skeleton of
organic spongin fibers
o “Sponges” are the spongin net after the living tissue has decomposed and
washed away
Gas Exchange
Circulation of water through spongocoele provides gas exchange & waste removal
Three Body Types
Ascon: simple urn shape, pores open directly into the spongocoeole
Sycon: pores open radial canalsspongocoele
Leucon: pores  incurrent canals flagellated chambers  radial canals 
spongocoele (one or several)
Porifera Classes
Class: Calcispongiae
Ascon shape
Spiculues: calcium carbonate (basically bone)
Class: Hexdtactinellida
Sycon shape
Spiculues: silicon oxide based (basically glass)
Class: Demospongiae (commercial sponges)
Leucon shape
Spicules: sponging fibers
Reproduction
Sexual Reproduction
Hermaphrodites (contain sperm & eggs)
Internal fertilization
release sperm carried by water to another sperm  fertilization
External fertilization
release sperm & eggs into water  fertilization
Asexual Reproduction
Fragments break off and make a new sponge (budding)
Osculum
Typical Sponge Features
Large opening at the top, water & wastes expelled
Sponges no bigger than a pen can move 20L of water through its body per day
Pore Cell
Surrounds each pore, bring water carrying food and oxygen into sponge’s body
Epithelial cell
“skin” cells, thin and flat, contract to touch or chemicals, close up pores, protect pores
Collar Cell
Line interior of sponges, has flagellum, draws water through the pores
Amoebocytes
Located between two cell layers
Spicules
Small, needlelike structures, located between layers, provide structure & protection