PORIFERA
http://www.insidesocal.com/tv/612~SpongeBob-SquarePants-Posters.jpg
The best Porifera of all! 
Period six
By: Matt Figueroa and Paige Cornwell
 What
stays in one place, lives in the water,
and eats minuscule organisms?
No,
it's not a Venus's fly-trap with a scuba
tank, it's the carnivorous sponge!
PORIFERA
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Porifera are also known as Sponges.
Sponges are among the oldest known animal
fossils, dating from the late Precambrian.
About 5,000 species worldwide
About 25 species in freshwater
They have no organs or tissues; cells are
somewhat independent.
composed of three distinct groups, the
Hexactinellida (glass sponges), the
Demospongiae, the Calcarea (calcareous
sponges), and Sclerospongiae
Class Calcarea
1. These are calcareous
sponges with spicules of
calcium carbonate.
2. The spicules are straight or
have three or four rays.
3. Most are small sponges
with tubular or vase shapes.
Spicules - A small needlelike structure or part, such as one of
the silicate or calcium carbonate processes supporting the
soft tissue of certain invertebrates, especially sponges.
http://seanet.stanford.edu/Porifera/leucandr_hea580.jpg
Class Hexactinellida
1. These are glass
sponges with six-rayed
spicules of silica.
2. Most are radially
symmetrical.
3. There are about 500
species. They occur
mainly in deep, cold
waters between 200 2000 m, although some http://tolweb.org/tree/ToLimages/staurocalyptus1.200a.jpg
can be found below 6000.
Class Demospongiae
1. This class contains 95%
of living sponge species.
2. Spicules are siliceous
but not six rayed; they
may be absent or bound
together by spongin.
3. Demospongiae are
often brightly coloured.
4. All are marine except
for Spongillidae, the
freshwater sponges.
http://www.lvp.com/data/mso2007/SCUBA%20SPONGES.jpg
Class Sclerospongiae
1. Small group of sponges
that resemble corals.
2. Found in dark tunnels in
coral reefs.
3. The skeleton consists of
siliceous spicules and
spongin on a thick
basal layer of calcium
carbonate.
4. a soft body that covers a
hard, often massive
skeleton
Body Plan
• No definite symmetry.
• Body multicellular, few tissues, no organs.
• Cells and tissues surround a water filled
space but there is no true body cavity.
• Often have a skeleton of spicules.
Feeding
• Water flowing through sponges provides food and
oxygen
• In general, sponges feed by filtering bacteria from the
water that passes through them.
– Some sponges trap roughly 90 percent of all bacteria in the
water they filter.
• Harbor symbionts such as green algae, dinoflagellates,
or cyanobacteria to derive nutrients.
• Capture small crustaceans with their spicules which act
like Velcro when they come in contact with the
crustacean exoskeletons.
– Cells then migrate around the helpless prey and digestion takes
place extracellularly.
Respiration
• Takes in water through its pores
– in more advanced forms, with canals that
move the water to all throughout the sponge
• Oxygen from the water is diffused into the
cells of the organism
– Rates of respiration depend on the
concentration of oxygen in the water
• Respiration takes place extracellularly
– Sponges have no respiratory organs
Circulation
• Water is drawn into the sponge through a
series of incurrent pores, or dermal ostia
– Enters central cavity
– Exits the sponge through a large opening at
the top called the osculum
• Rate of circulation depends on current of
water
– Oxygen and other nutrients diffuse into the
cells as it passes through the body cavity
Excretion
• Just as in respiration and circulation,
excretion depends on the movement of
water
– Wastes such as ammonia and carbon dioxide
are diffused into surrounding water
– The water is then carried away due to current
Response
• Sponges have no nervous or sense
organs
– Simplest contractile elements
• Protects itself by producing toxins that
make themselves poisonous to
predators.
– Interestingly, one of these is being tested to
treat cancer (a Caribbean sponge)
Movement
• Sponges are generally sessile
– Meaning they do not physically move
– The only movement observed in a sponge is
the opening and closing of pores
• Some observed to move up to 4mm per day within
aquaria
– May attach to organisms such as hermit crabs
to use as transportation
• Larvae of the sponges are free moving
Reproduction
• Asexually
– fragments that break off from the parent animal may
become new sponges
– gemmules: collections of amoebocytes within a hard,
protective outer layer
• Sexual reproduction in sponges is highly specialized
– External: the sperm and egg cells shed into the water
– Internal: sperm cells are carried by the water currents
out of the osculum of one sponge and into the interior
cavity of another sponge
• Most kinds of sponges are hermaphrodites
Works Cited
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"Phylum Porifera: Sponges ." infusion.allconet.org. N.p., n.d. Web.
19 Apr 2010.
<http://www.infusion.allconet.org/webquest/PhylumPorifera.html>.
"Porifera: Life History and Ecology ." ucmp.berkeley.edu. Berkeley,
n.d. Web. 19 Apr 2010.
<http://www.ucmp.berkeley.edu/porifera/poriferalh.html>.
Myers, P. 2001. "Porifera" (On-line), Animal Diversity Web.
Accessed April 20, 2010 at
http://animaldiversity.ummz.umich.edu/site/accounts/information/Por
ifera.html.
Johnson, Raven. Biology. 6th. New York: McGraw Hill, 2002. 884885. Print.