Delyan KaragerovIordan Milenkov

Radoslav Kokinov10/4

What are Cnidarians and Sponges Cnidarians are a group of aquatic animals

that include hydras, corals, jellyfish and sea anemones(1).

Sponges are the simplest multi-cellular animals. They come in a variety of colors, shapes and structures(3). Sponges don’t have internal organs and lack true tissues.

Do they have any symmetry? Cnidarians have radial

symmetry (2)

Sponges are asymmetrical (4)

Where do they belong in the Evolutionary Tree?Cnidarians Domain: Eukaryota Kingdom: Animalia Phylum: CnidariaSponges Domain: Eukaryota Kingdom: Animalia Phylum: Porifera

Relationships and ancestry Nowdays, scientists think that cnidarians

are very closely related to calcareous sponges(5).

Sponges appeared about 600 mya and are the oldest animal phylum extant today(5)

Cnidrians appeared about 580 mya. It is believed that the movement of all animals has started with cnidarians.

Cnidarians Gastrovascular Cavity – Internal sack for

digestion; it has only one opening (called “mouth”) through which pass both food and waste; round the mouth there are tenticles

3 layers: Epidermis; Mesoglea; Gastrodermis; Epidermis: outer layer; includes cells that provide

movement, cells that create eggs and sperm, and some unique for the cnidarians cells (cnidocytes); nematocysts(inject toxins to other organisms)(12); (13)

Sponges No organs or body systems (they are the

simplest multicellular animals) The digestion of food happens in the cells

only Don’t move (filter feeders) Can reproduce both sexually and asexually Their skeleton is composed of two parts: Soft part – sponging

Hard Part – Spicules(13)

Filter-feeders /very efficient/ (7)

Have large inside volume; cells that have a sticky collar and flagella /Choanocytes/ on the walls (7)

The flagella force water in and out of the sponges’ inside volume, bringing in food and oxygen and excreting waste. (7)

The food particles get caught by the collar cells and are transported within the sponge by Amebocyte cells (7)

Most of the Sponges are hermaphroditic Male and female roles are obtained >>>May switch next time (6)

The ‘male’ sponges releases sperm/gametes/ >> ‘female’ sponge fertilized internally

>> larvae is produced. (7)

The larvae floats in the water >> settles down and starts growing. (7)

Asexual reproduction (7) -by internal/external budding or a piece of the sponge may break off

Sponges don’t move (7)

They settle in a place, start growing and are anchored/stuck to a rock or etc. (7)

Encrusting sponges- cover rocks like moss does(6)

Free-standing sponges- grow bid in size; large inner volume; look like big funnels/chimneys (6)

Most are carnivorous /eat crustaceans ,etc./ (8)

Corals – filter water- absorb dissolved nutrients OR depend on endosymbiosis /e.g. algae/

Medusas – uses tentacles/+nematocyts/ + oral arms to catch the pray and paralyze it. Bring it to the mouth /gastro vascular cavity/ where enzymes are secreted and break down the food. Flagella mix the enzymes and food until it’s fully digested. Waste excreted (8)

Sea anemones/hydras – Same but don’t catch - wait for pray to pass by.

Diffusion or mesoglea cells (9)

Sexually:1.A small larva is produced /planula/ (8)

2.it settles to the seafloor -develops into a polyp (8)

3.the polyp divides into a colony (8)

– medusas are ‘shed off’ and mature– corals and sea anemones stay as polyps (8)

Asexually: (8)

By budding or splitting down the middle

Corals- stay anchored to a spot without moving (9)

Medusas –swim freely or get dragged by currents or- ‘jet propulsion’: force water out their inside cavity by contracting muscles (9)

Hydras and sea anemones-mostly stay put and anchoredbut can detach and glide slowly using their tentacles / if the conditions require it/ (9)

Hydra Vulgaris

Around 12mm in size Live in most unpolluted sources of fresh water Food: They eat small aquatic invertebrates like Daphnia

and Cyclops When eating Hydra stretches its body and tentacles and

uses the tentacles to catch the prey, and to enclose it into its body cavity. (Nematocysts very important)

Locomotion: When attacked hydras most often retracts its tentacles and body column to small sphere. (no matter where the attack came from); Although hydras usually don’t move (sessile) they do occasionally move a little… especially when hunting: Hydra vulgaris releases its grip (applied by its base called foot) of the object that it had been clung to, and lets the water flow move it. (16)

Life cycle: When conditions are good reproduce asexually (producing buds, that grow and break away from its body); In winter – they reproduce sexually

Sexually: They form miniature ovary or testes in the body wall; the testes release free-swimming gametes into water, and they fertilize the eggs of the ovary of another individual;

http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Hydrozoa/Hydra_vulgaris_polyp.jpg/medium.jpg

Scleractina (Stone Corals)

Most are between 1 and 3 millimeters Can be found in clear, shallow tropical waters; it is the

main creator of the coral reefs Feed on many small organisms such as zooplankton and

even some really small fish or vertebras. Like all Cnidarians, it uses the nematocysts in the

tentacles to immobilize or kill its prey(if it is bigger); then the tentacles bring the prey in to the body cavity

However, like many other planktons it may undergo a process called zooxanthellae in order to obtain food; it basically uses some elements of photosynthesis on a cellular level.

Just like all other corals, it doesn’t move.(16)

Reproduction Sexual There are 2 methods of sexual reproduction in

corals that differ in whether or not the female gamete is released:

About 75% of the cases corals form organism called Broadcasters, majority of which are reef-building.

In the other 25% of the cases they form brooders that are not reef-building. In both cases the result is a primary polyp. Then it uses asexual reproduction to form a mature colony.(16)

http://www.hausriff.ch/media/DIR_141851/ima4.jpg

Gelliodes Fibrosa Aka:Gray encrusting sponge Varies in size between 15mm and 180mm Live in shallow waters around the Hawaiian islands Food: filter water and the microscopic food particles

in the water are captured by specialized collar cells. The particles then are digested intracellular.

Reproduces both sexually and asexually Can live up to 200 years or more. Sessile animal (Don’t move; although some

sponges move when they are really young)(15)

Some jellyfish are eaten in orient cousin (10)

Many are harmless

BUT some jellyfish and corals are extremely toxic to humans- lethal “Sea wasp" Chironex fleckeri (10)

Coral riffs create the best beaches (10)

Fun Fact The Great Barrier reef is the biggest single

structure made by living organisms. The only living thing on Earth that can be

seen from outer space. Approximately 25 million years old Built by billions of coral polyps.

http://cdn.sheknows.com/articles/great%20barrier%20reef%20google%201%281%29.jpg

http://www.animalport.com/img/Cnidarians.jpghttp://www.brandoncole.com/profile%20photos/INVERTEBRATES/cnidarians/ha834-purple_jellyfish_brandon_cole.jpghttp://genome.jgi-psf.org/Nemve1/Nematostellapolyp.jpghttp://batiburrillo.redliberal.com/imagenes/El%20caso%20de%20las%20Medusas.jpghttp://www.afrmc.org/images/jellyfish.jpghttp://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Avispa_marina.jpg/337px-Avispa_marina.jpg http://www.arcodiv.org/watercolumn/cnidarian/images/Chrysaora_melanaster_400x300.jpghttp://www.lvp.com/data/mso2003/SCUBA%20SPONGES.jpg1. "Cnidaria." About.com: Animals/Wildlife. New York Times Company. Web. <http://animals.about.com/cs/cnidaria/g/cnidaria.htm>. 2. "Radial Symmetry." About.com: Animals/Wildlife. New York Times Company. Web.

<http://animals.about.com/od/cnidarians/ss/cnidarians_2.htm>. 3. "Sponges - Porifera." About.com: Animals/Wildlife. New York Times Company. Web.

<http://animals.about.com/od/sponge1/p/porifera.htm>.4. "All About Sponges." Tree of Life Web Project. Tree of Life. Web. <http://tolweb.org/treehouses/?treehouse_id=3431>. 5. "Cnidaria." Wikipedia. Wikimedia Foundation Inc. Web. <http://en.wikipedia.org/wiki/Cnidaria>. 6. "Sponges". 2002 Missouri Botanical Garden. 30.03.2010 <http://www.mbgnet.net/salt/coral/animals/sponges.htm>. 7. Bird, Jonathan. "SPONGES: They are Nothing Like Sponge Bob! ". Oceanic Research Group. 30.03.2010

<http://www.oceanicresearch.org/education/wonders/sponges.html>. 8. Morris, Matthew . "Phylum Cnidaria". AAA Matilda Canada . 30.03.2010

<http://www.angelfire.com/mo2/animals1/phylum/jellyfish.html>. 9. Klappenbach, Laura . "Cnidarian Characteristics". About.com. 30.03.2010 <http://animals.about.com/od/cnidarians/ss/cnidarians.htm>. 10. Klappenbach, Laura . "Interaction with humans". Wikipedia: The Free Encyclopedia. 30.03.2010

<http://en.wikipedia.org/wiki/Cnidaria#Interaction_with_humans>.

12. Klappenbach, Laura. "Characteristics of cnidarians". 29.03.10 <http://animals.about.com/od/cnidarians/ss/cnidarians.htm>.

13. "Sponges&Cnidarians". 29.03.10 <http://www.biologycorner.com/bio1/notes-sponges_cnidarians.html>.

14. "Coral Reef Fact". 29.03.10 <http://www.barrierreefaustralia.com/the-great-barrier-reef/coralfacts.htm>.

15. "Gelliodes fibrosa". 29.03.10 <http://www2.bishopmuseum.org/HBS/invertguide/species/gelliodes_fibrosa.htm>.

16. “Cnidarians”.29.03.10www.wikipedia.org

17.”Sponges”.29.03.10.<www.wikipedia.org>