Cnidarian


 * __ Cnidarian __**

__**Basic Structure**__
 * Cnidocytes are specialized cells unique to Cnidarians. They contain stinging structures, mucus-secreting cells and receptor and nerve cells which collect and transmit sensory information. Cnidarias have a sac inside of them for disgestion which is called the gastrovascular cavity. It only has one opening which is a mouth. That is where the animal takes in food and releases waste. Tentacles expand outward from the rim of the mouth. The body of the cnidarian has three layers. The outer layer is called the epidermis, the middle layer is the mesoglea and the inner layer is known as the gastrodermis. The epidermis has a large amount of different types of cells. These include epitheliomuscular cells which shrink and enable movement. Also includes interstitial cells that give and rise to many other cell types like egg and sperm.

__**Unique Facts**__ be alive over 650 million years ago. Cnidarians have nematocysts which are special stinging cells that can kill prey. The nematocysts have paralyzing toxin within them that kills their prey. The nematocyst is a little barbed wire shot from the stinging cell. Not all Cnidarians have nematocyst. All cnidarians are radically symmetric. Although cnidarians are very advanced, they lack many of the features of more advanced animal phyla, such as internal organs and central nervous systems. Cnidaria comes from the Greek word "Cnidos," which means stinging nettle. The biggest jellyfish in the world is the Artic Lion’s Mane and they have tentacles that grow up to100 feet. The Australian box jelly or sea wasp is the most poisonous jellyfish in the world. Jellyfish can have up to 800 tentacles. A coral reef can contain over 1500 types of fish. Cnidaria is an extremely primitive animal phylum. It consists of aquatic organisms such as jellyfish, sea anemones, corals, and hydras. Most cnidarians are of the marine type but, a few such as the hydra, are freshwater species.
 * They were among the first multicellular organisms to

__**﻿ Species Number**__
 * There are over 10000 known species of Cnidarian.

__**Classes of Animals in the Phylum**__
 * Classs Hydrozoa
 * Class Scyphoza
 * Class Cubozoa
 * Class Anthoza

__**Phylogenetic tree of the classes**__


 * __**Feeding Mechanisms**__
 * Cnidarian’s have tentacles that have stinging cells in their tips. These stinging cells are called cnidocytes, and within these cnidocytes are nematocysts which are coiled thread-like stingers.
 * Cnidarians use these tentacles to capture and subdue their prey.
 * In Polypoid Cnidarians such as corals and anemones, their tentacles are upright, and in Medusiod Cnidarians such as Jellyfish, these tentacles are downward.
 * Cnidarians are carnivores, eating a multitude of small organisms, crustations, and small fish, but they don’t pursue their prey like most carnivores.
 * Cnidarian’s lay in wait for their prey to swim into their tentacles rather than chasing them.
 * Jellyfish, for example, float and wait for their prey to swim into them. They can have extremely long tentacles which fish swim through, not seeing the Jellyfish’s body high above, and are stung.
 * When Cnidarian’s attack their prey, the Nematocyst uncoils and becomes almost like a little harpoon. It punctures through the cnidocyte wall and into their prey.
 * Most Cnidarians also have a toxin in their tentacles that can be released through either touching their prey or through a neurological impulse.
 * After the tentacles have captured and killed the Cnidarians prey, they bend, bringing the food to its mouth.
 * They have a internal sac for digestion called the gastrovascular cavity
 * The gastrodermis is the inside part of the organism and has cells to digest and and absorb nutrients
 * When the prey is inside the cavity the Cnidarians releases enzymes to digest it
 * Some special Cnidarians have additional ways of capturing their prey, like coral. Some species of coral expel a mucous from their mouth called cilia. These cilia are sticky and can capture small organisms that swim by.
 * Pink, orange, red, and brown Cnidarians are commonly pigmented by the crustaceans they eat, which contain carotenoids.
 * Some corals, medusae, hydras, and sea anemones contain golden-brown algae, and green algae which they can’t digest, but are able to obtain vital nutrients such as glucose and oxygen from.
 * Cnidarina’s obtain the nutrients and food they need to survive primarily through using their tentacles armed with stingers and toxins, but they also have many unique and interesting ways of feeding as well.

__**Scientific species names of of Phylum**__ > Scyphozoa- (cup animals and jellyfish
 * [[image:scyphozoa.jpeg]]
 * Cubozoa- (sea wasps of box jellyfish)
 * Anthozoa- (anemones and corals)[[image:anthozoa.jpeg]]
 * Hydrozoa- (hydralike animals, hydroids, and hydrozoans)[[image:hydrozoa.jpeg]]
 * Trachylina [[image:trachylina.jpeg]]

__**Geographic Distribution**__
 * Cnidaria live all over the world in mostly the salt water regions. They can live from in the bottom of the ocean to the very shallow waters of any of the oceans in the world. The Cnidarians are usually found in seas and oceans. They live in coral reefs as coral, and as jelly fish throughout the whole ocean. These unique and beautiful creatures can be found almost everywhere.
 * __Reproductive Methods __**
 * Cnidarians have specialized gonads.
 * Cnidarians are both asexual and sexual reproducers.
 * As the eggs and sperm are produced within themselves, asexual reproduction begins to occur.
 * Asexual reproduction is a fast process for cnidarians. They produce of genetically identical clones. Asexual reproduction is often done preferable conditions like during spring and summer.
 * Sexual reproduction is a slow process. They produce different offspring every time. Sexual reproduction usually occurs during poor conditions like in fall.
 * Sexual reproduction is a slow process. They produce different offspring every time. Sexual reproduction usually occurs during poor conditions like in fall.

__Ecological Niche__ (“job” as a member of the environment)  •Cnidarians use their cnidocysts to trap prey items. Many Cnidarains depend on zooxanthellae, or symbiotic dinoflagellates within the tissues, to survive. •Cnidarians have stinging cells like corals and anemone. They capture food as it floats by.

__**References**__

"Anemone." Valdosta State University. Web. 23 Feb. 2011. [|http://www.valdosta.edu/~jlgoble/topic.html].

"Cnidaria" newworldencyclopedia.org Feb 16 2011

[|**http://www.newworldencyclopedia.org/entry/cnidaria**]

"Cnidaria.html." College of Science & Mathematics. Web. 16 Feb. 2011. [|http://science.kennesaw.edu/~jdirnber/InvertZoo/LecCnidaria/Cnidaria.html]. “Cnidarian.” Encyclopedia Britannica. Encyclopedia Britannica Online. Encyclopedia Britannica, 2011. Web. 16 Feburary 2011. [].

“Cnidarians: Simple Animals With A Sting.” Oceanic Reseach. Oceanic Research Group. Web. 16 Feburary 2011. [|www.oceanicresearch.org/education/wonders/cnidarian.html]

"Cnidarians." //Saddleback// //Valley Unified School District//. Web. 16 Feb. 2011. [] "Cnidaria Can Undergo Asexual and Sexual Reproduction." //Christian Brothers University//. Web. 23 Feb. 2011. [|http://www.cbu.edu/~seisen/Cnidaria/sld010.htm].

"Cnidaria.html." College of Science & Mathematics. Web. 16 Feb. 2011. . "Google Images." Google. Web. 16 Feb. 2011. []. Klappenbach, Laura. "Cnidarians - Characteristics of Cnidarians." //Animals Wildlife - Animal Facts, Animal Pictures, Habitat Facts, Evolution and Zoology//. Web. 16 Feb. 2011. []. .   "Www.ScubaPhoto.com Visits Palau in 2002." //Www.ScubaPhoto.com Underwater Photography//. Web. 23 Feb. 2011. [].**By: Lauren Fecura, Amie Skoda, Tyler Brennan, Ian Cutting, Tyler Colvin, Kendyl Lamphere, Allison Barber and Tony Nicchi.**