AP Biology Classification Project
Porifera,Cnidarians,Rotifera
By: Amin Syed and Marwa Saleh
Structure:
PORIFERA- THE SPONGES
Sponges lack symmetry but very few small
sponges are radially symmetrical
Poriferas are multicellular which means that
their cells are specialized for different
functions of the body
Sponges are sessile (they do not move)and
they attach themselves to something solid, but
larval sponges are free-swimming.
Sharon. (2011). The porifera (sponges). Retrieved from
http://sharon-taxonomy2010p2.wikispaces.com/Porifera
The outer layer of a sponge is called
the epidermis layer. They are made up
of epithelial cells. Porocytes regulate
water flow and they are located around
pores. Some portions of the layers
contract (some pores close) when they
are touched or exposed to chemical
stimuli. The Internal cavity
(spongocoel) has specialized
flagellated cells called Choanocytes
(collar cells). The lining of the
choanocytes creates an inner layer
(gastrodermis). These cells line the
entire body cavity.
Sponges also consist of mesohyl
between body cavity and the outer wall
Mesohyl are gelatinous, protein-rich
matrix. That’s where amoeboid cells
are located. Amoebocytes secrete hard
mineral needles called spicules and
tough protein fibers called spongin.
Both of these structures strengthen
and protect the sponge, provide the
support to keep the pores open.
Osculum which is a large pore where
water and chemicals leave.
Diversity:
PORIFERA- THE SPONGES
Sponges are classified in the kingdom
animalia.
The only phyla is Porifera but there are
four different classes. They are
Calcarea (chalky sponges with
calcium carbonate), Demospongiae
(they include glass sponges & Venus
flower basket with spicules),
Hexactinellida (they include horny &
bath sponges with only spongin or
spongin/silica spicules) ,and
Sclerospongiae (they are coral
sponges. They have spongin, silica,
and calcium carbonate spicules).
The subkingdom is Parazoa which
means that they lack tissue and
organs. They also lack nervous
system.
There are approximately 5150 species
Mode of nutrition:
Sponges are filter feeders. They remove
food (plankton) from water which is
brought through the pores (Ostia)
Then the flagella pulls in bacteria or
algae which then stick to the collars of
choanocyte. They are then passed to
archaeocytes who digest food.
The amoebocytes travel in the
mesohyl and pick up the food from
choanocytes and distribute to other
parts of the sponge. Because of the
amoebocytes, then finally water and
food that are not needed leave through
the osculum which is like a large hole
on top of the sponge.
They are heterotrophic consumers, they
ingest food meaning they digest
internally.
Reproduction:
PORIFERA- THE SPONGES
Sponges can produce asexually and sexually.
They produce asexually by external buds. They either break off to form new
sponges or they stay attached to form sponge colonies.
They also have specialized internal buds called Gemmules. Gemmules consists
of food-filled amoebocytes by a coat with spicules, they break their coat when
there are no harsh conditions and form new sponges. Sponges are
hermaphrodites (they produce both eggs and sperm) but they exchange sperm.
Mesohyl Is the location where sexual reproduction occurs. Male gametes are
released into water by the sponge and then it goes through the pores of the
neighboring sponges. Spermatozoa sticks to the collar of choanocytes, the
choanocytes then lose their collar and the collar turns into a specialized cell
similar to amoebocytes cells that carry spermatozoa to the egg. The fertilized
egg becomes the blastula (free-swimming larvae) and is released into water.
They settle and then are transformed into adult sponges.
Sponges can also reproduce by regeneration, where missing body parts are
regrown. No genetic modification techniques used because sponges are not
commonly used organisms.
Sharon. (2011). The porifera (sponges). Retrieved from http://sharon-taxonomy2010-p2.wikispaces.com/Porifera
PORIFERA- THE SPONGES
Ecological significance:
Some sponges may be used to find out new pharmaceutical compounds that can be
used on humans.
Because they are natural filters, sponges can remove pollutants and carbon dioxide.
They serve as protective houses for mollusks and small fishes. Small fishes who live
inside the sponge can take advantage of the food supply that is circulating in the water.
They have commensal relationship with shrimps because shrimp live inside them and
grow so large that its hard for them to leave through the osculum.
Sponges are pathological towards human like bacteria or fungi can be. So they are
harmless towards humans.
They can be used as products for cleaning
Several sponge species produce compounds that show great potential to be used as a
drug to cure malaria, tuberculosis and other infectious diseases.
Also, you can get a skin rash from sponges. Due to their defense mechanism of
releasing toxins.
Uniqueness:
They have a natural filter feeding
system.
Simplest mutlicellular organism.
They possess choanocytes and special
flagellated cells whose beating drives
water through the body cavity.
Examples:
PORIFERA- THE SPONGES
Tube Sponge: are very common and can be found in the coral
reefs. they are different because of they are long tube-shaped
and range in color from purple to blue, gray, and gray-green.
They are one of the few reef invertebrates that are blue In color.
Vase Sponge: common species found in the Caribbean. They have
a large bell shape with deep central cavity. grow up to 2 feet
wide and 3 feet high. ranges in color from purple to red and
brown, and most of them are attached to sandy bottoms.
Yellow Sponge: are commonly found through out the Pacific
coastal waters. Are found growing in small colonies, and ranges
in color from orange to bright yellow. They encrust rocks on
reefs.
Red Tree Sponge: are common throughout the Caribbean Sea.
They grow up to height of about 8 inches. They are very easy to
keep and can live easily in home aquarium environment. Also,
they require moderate water flow and dim light.
Structure:
Rotifera- Wheel bearer
The foot ends in a toe which contains cement gland- useful because it attaches itself to
objects in water and obtain food when it wants to.
They are transparent and are covered with a cuticle covering. This tells us that they are
closely related to roundworms and arthropods.
The food is chopped by trophi (jaws) which is located in the behind the mouth in the
pharynx (throat).
Head is the corona or crown of cilia which draws water into mouth and sifts for food.
They also use cilia to move themselves – some of them can walk with head and foot.
They are bilaterally symmetrical. There are four basic regions: head, neck, body, and
foot.
They have a body cavity which is lined by mesoderm.
They have specialized organ systems and a complete digestive tract which includes
mouth and anus.
For their nervous system, their nerves extend through out their body. They have five
eyes with one or many photoreceptors.
They have small brains and contain one ore two antennae.
Rotifera- Wheel bearer
Diversity:
They are very tiny- 200 to
500 micrometers long
Microscopic organisms.
They are the most common
microorganisms collected
from ponds and small lakes.
Their habitats are
freshwater, marine, or damp
soil.
They are divided into three
classes: Monogononta,
Bdelloidea, and Seisonidea.
Mode of nutrition:
The food particles are very
small so it can pass through
their mouths. Examples include
unicellular algae and
phytoplankton.
They complete their digestive
tract through gastrovascular
cavity. They use the alimentary
canal (a digestive tube with a
separate mouth and anus).
The crown of cilia draws water
into the mouth and pharynx
contains trophi or (jaws) that
grind up food, mostly
microorganisms suspended in
water.
For circulation, movement of
the rotifer body distributes the
fluid through out the body
which then circulates the
nutrients. It has an open
circulatory system.
There is no specific organ for
gas exchange so the only way
is through diffusion.
Rotifera- Wheel bearer
Reproduction:
reproduce asexuallly by parthenogensis, in which females
produce more females from unfertilized eggs
other species might produce two types of eggs that develope
by parthenogenesis. One type forms females,other type
develops when conditions deteriorate and become simplified
males that can not even feed themselves
males only survive long enough to fertilize eggs, which form
resistant zygotes that can survive when a pond dries up
zygotes break dormancy and develop into a new female
generation
Rotifera- Wheel bearer
Ecological Significance:
Important ecolofical
role as suspension
feeders on
phytoplankton and
bacteria
Trophic Link-food
source for larval
fishes
Sewage treatment
Ephemeral WatersAbility to survive
dessication
Uniqueness:
Only reproduce
asexually
seudocoelomates
fluid in their
pseducoelom serves
as a hydrostatic
skeleton
smaller than
protists, but more
anatomically
complex than
flatworms
Rotifera- Wheel bearer
Examples:
Philodina roseola–This class of rotiferas do not have a cuticular covering, males have never been
observed, and the females appear to be obligatorally parthenogenic. They can survive extremes
of temperature and desiccation for years. As these were the first rotifers to be described, they
were given the common name of "Wheeled animacules". Class Bdelloidea.
Rotifer neptunis-is 1 mm long when fully extended, but can retract its body like pushing in a
telescope until it is a third of this length. The females produce live young. Class Bdelloidea.
Hydratina senta- This is the marine Class; they are relatively large and live in the gills of
crustaceans. Class Seisonidea.
Keratella quadrata-This class of rotifera contains the largest number of species. There are both
freshwater and marine species. Sexual reproduction has been observed, although males are
absent for most of the year, and much smaller than females. Class Monogonata
Cnidarians-Jellyfish,Hydra,Corals and
Sea Anemones
Structure:
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Cnidarians have two body forms, Polyp and
Medusa. These two phases alternate in the
life cycles of the cnidarians. But a number of
the cnidarian species exist only as polyps for
example the Corals and Sea anemones.
Both forms have two layers, the epidermis
(the outer layer) and the gastrodermis ( the
inner layer that has the digestive tissues.
These two layers are separated by the
mesoglea, a geleatinous material that holds
the muscles for most cnidarians.
Polyps are cylindrical and are usually found
attached to a substrate on the floor of ocean.
The mouth faces away from the substrate the
polyp is attached to, therefore often faces
upward with its tentacles pointing upward.
Polyps build up a chitinous or calcareous
external or internal skeleton or polyp or both.
Medusae are free-floating and umbrella
shaped. Their mouths point downwards
surrounded by their venomous tentacles.
The tentacles and sometimes the body
surface bear cnidocyte cells, which secrete
Nematocyst, which is a barbed or venomous
coiled thread that can be projected in selfdefense or to capture prey.
Cnidarians-Jellyfish,Hydra,Corals
and Sea Anemones
Diversity:
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Cnidarians are classified in the
animialia kingdom.
Cnidarians have three main
classes: Anthozoa (corals)
,Hydrozoa (hydras) and
Scyphozoa (jelly fish).
Anthozoa-can be either solitary
or colonial. Common forms
include corals and seaanemones. They differ from
other Cnidarians in that they
have no medusoid stage.
Hydrozoa-have calcified
skeletons of aragonite and
calcite.
Scyphozoa-only occur in marine
environments. And the majority
of species in this class are
jellyfish.
There are approximately 10,000
specimens of cnidarians
Mode of Nutrition:
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Cnidarians vary in diet due to the
variety of different species.
Their diet ranges from,
phytoplankton to small fish.
For specifically jellyfish,
Nematocysts fire on contact;
after paralyzing its prey, it pushes
the food into its mouth with its
tentacles
Food is pushed into the central
cavity where gland cells release
enzymes in order to digest food.
Other cells of the endoderm will
then absorb the digested
nutrients. Indigestible material
will then be eliminated out of the
mouth.
Cnidarians-Jellyfish,Hydra,Corals
Reproduction: and Sea Anemones
• Both the polyp and medusae forms
consist of diploid individual.
• Polyps reproduce asexually, by simply
budding with the neighboring polyps.
When doing this they can either produce
another polyp or a medusae.
• Cnidarians exhibit open-water
fertilization
• Medusae reproduce sexually. The male
organisms release sperm into the water
and it is collected by the female, who
then releases the fertilized eggs that
become free swimming larvae called
planulae.
Cnidarians-Jellyfish,Hydra,Corals
and Sea Anemones
Ecological Significance:
Coral reefs are a shelter for
many marine animals.
Coral reefs provide habitat for
many fish and food for many
other animals that produce
valuable shells, pearls, and
jewelry.
Medical research of chemicals
produced by many Cnidarians,
contributed in the creation of
new antibiotics and anticancer
chemicals
Uniqueness:
They were among the first
multicellular life to evolve
on earth.
They have been here for
at least 650 million years.
Their most obvious unique
feature is their highly
specialized stinging cells.
Cnidarians-Jellyfish,Hydra,Corals
and
Sea
Anemones
Examples:
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CLASS HYDROZOA-Members of this class include the Hydra, Obelia, and Gonionemus.
Most members of this class have both the polyp and medusa stages yet, Hydra exists
only in the polyp form.
CLASS SCYPHOZOA -Animals in this class are entirely marine. The polyp stage is reduced
or absent. This class mainly includes jellyfish species.
CLASS ANTHOZOA - the term anthozoa means "flowering animals“. They exist in the
sessile polyp stage only; no medusa stage is present. This class includes the sea
anemone and sea coral.
CLASS CUBOZOA-have a square shape when viewed from above. They also have four
evenly spaced out tentacles or bunches of tentacles.
References
 Fautin, Daphne G. and Sandra L. Romano. 1997. Cnidaria. Sea anemones, corals, jellyfish, sea pens, hydra.
Version 24 April 1997. http://tolweb.org/Cnidaria/2461/1997.04.24 in The Tree of Life Web Project,
http://tolweb.org/
 Morris, Matthew May 15 2003. Phylum Cnidaria.
http://www.angelfire.com/mo2/animals1/phylum/jellyfish.html
 Ward, Paul. 2005-2012. Cnidaria – Cnidarians.
http://www.darwinsgalapagos.com/animals/cnidaria_jellyfish_coral_sea_anemone.htm/.http://www.darwinsg
alapagos.com
 McGraw-Hill companies.(2002). The Noncoelomate Animals. In Raven/Johnson, Biology(pp.884-889). New York:
McGraw-Hill Publisher.
 McDarby Michael. (2001-2011). An online introduction to the biology of animals and plants [Web
log message]. Retrieved from
http://faculty.fmcc.suny.edu/mcdarby/animals&plantsbook/animals/02-Sponges&Cnidaria.htm
 bumblebee.org. (1997-2012). Retrieved from
http://www.bumblebee.org/invertebrates/Porifera.htm
 Myers, P. 2001. "Porifera" (On-line), Animal Diversity Web. Accessed February 20, 2012 at
http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html
 Sea sponges. (2012). Retrieved from http://www.allthesea.com/Sea-Sponge.html
 Baqai , A. (2000, June 08). Retrieved from
http://www.ucmp.berkeley.edu/phyla/rotifera/rotifera.html
 Sharon. (2011). The porifera (sponges). Retrieved from http://sharon-taxonomy2010p2.wikispaces.com/Porifera
 bumblebee.org. (1997-2012). Retrieved from
http://www.bumblebee.org/invertebrates/ROTIFERA.htm
 Integr. Comp. Biol. (2002) 42 (3): 660-667. doi: 10.1093/icb/42.3.660 .
http://icb.oxfordjournals.org/content/42/3/660.full