Video:What Is Phylum Chordata?with Holly Deambrosi
Phylum chordata is a classification in the animal kingdom that groups together species with common traits. Watch this video from About.com to learn more about how these animals are all related in the phylum chordata.See Transcript
Transcript:What Is Phylum Chordata?
Hi, I'm Holly Deambrosi for About.com. What do fish, amphibians, reptiles, birds and mammals have in common? They all belong in the phylum chordata, members of which are also known as chordates.
Chordates Have a Notochord
All chordates are characterized by the presence of a notochord, or internal, supporting skeletal rod, in some stage of their development. In some cases the notochord is present only in the embryonic stage. Most chordates are vertebrates, but there are also two categories of invertebrate chordates.
Common Features Characterize Chordates
Some of these features include the presence of bilateral symmetry, an endoskeleton, body segmentation, a complete digestive system and a tail. All chordates have bilateral symmetry. For example, if a line is drawn directly down the middle of this frog, you will notice that it is essentially divided in half with each side being symmetrical, or a mirror image of the other.
Chordates Have an Endoskeleton
This internal, supporting framework may be bony or cartilaginous, such as in sharks or young vertebrates. Body segmentation is simply the division of the body into regions, such as the head, trunk, legs and feet. The presence of a complete digestive system in chordates indicates two openings for the digestive tube so that food and waste do not mix. The tail may be present only in embryonic form, as in tadpoles, otherwise this feature is present through the adult stage.
Animals in Phylum Chordata
So now you know some of the basics about chordates, can you think of more examples of phylum chordata? Which of these examples is a chordate? (sea turtle, sea star, jellyfish) This one should be pretty easy. Look at the sea star and the jellyfish. Both of these animals have radial, not bilateral, symmetry. Neither has a tail or formal body segmentation. So we know right away that neither of these is a chordate. The sea turtle is a vertebrate, has a tail, a complete digestive system, body segmentation, is bilaterally symmetrical, and is classed as a reptile. The sea turtle is a chordate.
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