Chordata

= Phylum: Chordata =

What is Phylum Chordata/ What are Chordates?
Most organisms under the Chordata phylum, or chordates, have a vertebrate, but not all. Characteristics all chordates have, or had at some time in their life span, include pharyngeal slits, dorsal nerve cord, notochord, post-anal tail. Pharyngeal slits are "holes" that connect the inside of the throat to the outside of the neck, more commonly known as gills. A dorsal nerve cord is many nerves down the back connecting the organisms brain to the muscles in its body. The notochord is a structure consisting of cartilage that supports the nerve chord that leads to the brain. A post-anal tail is where an organism has an opening where the tail would have gone, for example on a human there's a tailbone because we used to once have tails, but we don't anymore. Chordates produce sexually, not through pollination or asexually. Chordates have bilateral symmetry. Which means that they can be cut down the middle one way and are equal on both sides, externally. For example If you were to cut a frog in half, from head to toe, then it'd be equal on both sides. A coelomate is an organism with a body cavity, much like a human. A pseudoceolomate is an organism that has a fake body cavity, much like a worm. Acoelomates are organisms that have no body cavity much like a sea jelly. Our phyla, Chordate, are classified as Coelomates because there are organisms with a body cavity.

What are the Subclasses of Chordata?
 A **Tunicate ** is a subphylum of the Chordate phylum. It is a group of underwater filter feeders. They are sac-like creatures. Most of these Tunicates live on the ocean floor, while others live free-floating. There are about 3000 species of tunicates and these species are broken up into different classes. Another subphylum of the chordate phylum is a** Cephalochordata **. A Cephalochordata is a subphylum that is represented by the attendance of a notochord. A notochord is a rod-shaped body that is flexible that is found in embryos of all chordates. This species. There is also a **Craniata **. It is a subphylum of chordate that have a hard bone or skull. They include hagfish, lampreys and jawed vertebrates.

What Organisms are in Phylum Chordata?
Organisms in Phylum Chordata include fishes, amphibians, reptiles, birds, mammals. An example would be a clown fish. They have pharyngeal slits, gills, so that they can breathe in the water. Although not all chordates have their pharyngeal slits through out their life span, most only have pharyngeal slits during the embryonic stage. For example a cat doesn't have pharyngeal slits after leaving the womb because it had nostrils to bring in oxygen. While in the womb there isn't oxygen so the embryo needs to be able to breathe, so it has pharyngeal slits. Another example of a chordate would be an American Robin. Robins have a notochord, vertebrae or structure similar to a vertebrae, and a dorsal nerve cord. All chordates either have a vertebrae like structure made of cartilage or an actual vertebrae made of bone. The notochord is something that stays though out all chordates lives and isn't "temporary" for some chordates like the pharyngeal slits. The one difference between a human and a robin is that the robin still has a tail. Humans and some other chordates don't have a tail, they just have a post-anal tail. Another example of a chordate would be a Gorilla. They have a post-anal tail, dorsal nerve cord, and a notochord. They also had pharyngeal slits while in the embryonic state, but like birds they lose them after leaving the womb.

Why are Chordates Evolutionarily successful?
The phylum chordata is successful as a species because it has lived for so long and learned to adapt to the changes in the world. The ability to adapt is one of the most important abilities in nature, because the natural world has three choices. M.A.D. Move, Adapt, or Die. Most wouldn't want to die so they would have to move or adapt. Adaptation is the best choice because once you learn to adapt you can adapt to any and all changes over a certain period of time.

Quiz Time!
Now that you've learned about Phylum Chordata, here's a quiz that you can take to test your knowledge! http://www.mcwdn.org/Animals/ChordateQuiz.html = = =Sources Cited= "American Robin, Identification, All About Birds - Cornell Lab of Ornithology." //Your Online Guide to Birds and Bird Watching, All About Birds, Cornell Lab of Ornithology //. Cornell University. Web. 24 May 2011. . "Chordates." //Monroe County Women's Disability Network //. Web. 24 May 2011. . "Clownfish." //AC Tropical Fish & Aquarium //. Aquatic Community, 2004. Web. 24 May 2011. . Lundberg, John G. 1995. Chordata. Version 01 January 1995 (under construction). http://tolweb.org/Chordata/2499/1995.01.01 //in // The Tree of Life Web Project, http://tolweb.org/ http://www.ucmp.berkeley.edu/chordata/chordata.html http://www.britannica.com/EBchecked/topic/124179/coelomate

Phylum Chordata By: <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Matthew Wickens <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Theodore CoralloTitus <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;"> || <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;"> Bolded items are components of all chordates at some <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;"> point in their lifetime, and distinguish them from other phyla. || <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; text-decoration: none; vertical-align: baseline;">Chordata is a phylum in the animal kingdom, which holds 44,000 species of animals. Common examples of these would be humans, sharks, and dogs. These are all, despite their differences, Chordates, due to their similar characteristics. All of these are described under the following characteristics.
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">1 = bulge in __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|spinal cord] __ ("brain") ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">2 = **<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|notochord] __ ** ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">3 = **<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|dorsal nerve cord] __ ** ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">4 = **<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">post-anal tail ** ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">5 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|anus] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">6 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|digestive canal] __ ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">7 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|circulatory system] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">8 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|atriopore] __ ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">9 = space above __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|pharynx] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">10 = **<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|pharyngeal slit] __ ** (__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|gill] __) ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">11 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|pharynx] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">12 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|vestibule] __ ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">13 = oral __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|cirri] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">14 = mouth opening ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">15 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|gonads] __ (__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|ovary] __ / __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|testicle] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">16 = light sensor
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">17 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|nerves] __ ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">18 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|metapleural fold] __ ||
 * = <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">19 = __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|hepatic caecum] __ (__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[|liver] __-like sack) ||= <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 11.2px; text-align: start; text-decoration: none; vertical-align: baseline;">Anatomy of the __<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 14.6667px; text-align: start; vertical-align: baseline;">[|cephalochordate] __ //<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 14.6667px; text-align: start; vertical-align: baseline;">[|Amphioxus] __ //.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Characteristics of Chordata **

<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- A spine or some other variation of a notochord, which is a pole like structure going down part of the <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">line of bi-lateral symmetry of the body. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">-A follow nerve end at the beginning of the notochord. For us this is our skull. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- A central nervous system, going down this notochord. This explains why animals are paralyzed by the breaking of their spines. The central nervous system attached to it is then broken along with the spine. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- Segmented bodies, and muscles which explain why there are limbs like arms and legs. Furthermore this then shows why we are able to move and control our appendages. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- Have at some point in their life had gills or gill like structures. We had these in the womb but as time passed they developed into our ears. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- Have at some point in their life had a post anal tail. This again was more prominent in the womb. But it remains as our tailbone. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">- A body cavity known a coelom. This is the area between the organs and the body wall. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Common Classes of Chordata ** <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; text-decoration: none; vertical-align: baseline;">Chordata is labeled under the following six classes. First is Class Osteichthyes which makes up fish with bones such as trout. Class Chondrichthyes makes up fish with cartilage bones such sharks. Class Amphibia which makes up amphibians such as frogs. Class Reptilia makes up reptiles like snakes and lizards. Class Avia which makes up birds such as hawks and vultures. Finally Class Mammalia which makes up mammals such as humans.

<span style="background-color: #ffffff; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Chordate line of symmetry ** <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 34.6667px; text-align: center; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; text-decoration: none; vertical-align: baseline;">Chordates are a large verity of animals and have many different aspects. One of the main aspects of the Chordata Phylum is there symmetry. Chordates, and also vertebrates (which all are Chordates) have **<span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; vertical-align: baseline;">__<span style="background-color: transparent; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: center; text-decoration: none; vertical-align: baseline;">Bilateral Symmetry. __ __ **Bilateral symmetry is a unique type of symmetry; it means to be split in two. This means any animal that has Bilateral symmetry will have to identical sides. Look at humans, we have bilateral symmetry, we have an arm, a leg, an eye and many other parts on either side of our line of symmetry. This runs down from our head to crotch. In Chordates, the line of symmetry runs down their spines, because all chordates are vertebrates, (have spines) and that means it also has an internal support structure. Like humans, we have a skeleton which is made up of bones. <span style="background-color: #ffffff; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">What made this phylum evolutionarily successful? **

<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: #ffffff; color: #000000; font-family: 'Cambria','serif'; font-size: 14.6667px; text-align: start; text-decoration: none; vertical-align: baseline;">Chordates are one of the largest, and most successful animal phylum there is. And that is for one reason, advanced vertebrates. Vertebrates, or animals with spines, are all in the Chordata phylum, which means humans, are chordates. And humans are some of the most evolved animals in the entire animalia kingdom. Spines act as protection for the nervous system, and give us a strong support structure. Over millions of years, animals have evolved into complex beings, and the most successful bone structure, is vertebrates. Chordates are all part of the Earth’s most successful species, such as Humans, Apes, Fish, and any vertebrates. Chordates make up the majority of the carnivores and omnivores, and have proved that they are consistently, evolutionarily successful. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Cambria','serif'; font-size: 32px; text-align: center; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">Work Cited ** <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[] __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Lundburg, John G. "Chordata." //<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Tree of Life Web Project //. 1 Jan. 95. Web. 24 May 2011. <http://www.tolweb.org/Chordata/2499>. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[] __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Carter, J. Stein. "Phylum Chordata." //<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Biology at Clermont College - University of Cincinnati //. 04 Nov. 2004. Web. 24 May 2011. <http://biology.clc.uc.edu/courses/bio106/chordate.tm> <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Lundberg, John G. 1995. Chordata. Version 01 January 1995 (under construction). <span class="url" style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">http://tolweb.org/Chordata/2499/1995.01.01 //<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">in // The Tree of Life Web Project, <span class="url" style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="background-color: transparent; color: #0000ff; font-family: serif; font-size: 16px; text-align: start; vertical-align: baseline;">[] __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Bartlet, Graeme. "Chordate." //<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">Wikipedia, the Free Encyclopedia //. Wikimedia, 20 May 2011. Web. 24 May 2011. <http://en.wikipedia.org/wiki/Chordate>.