Chordata Practical

Chordata Practical - Chordata 1. 3 Subphyla of Chordata: 1)...

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Chordata 1. 3 Subphyla of Chordata: 1) Vertebrata 2) Urochordata 3) Cephalochordata 2. Characteristics of Chordata: 1) name of this phylum is derived from the dorsal stiff, yet flexible rod called the notochord 2) also has a dorsal, hollow nerve chord 3) presence of outpocketings of the pharynx called pharyngeal pouches; in primitive organisms they function in feeding; in other chordates the pouches close and eventually develop into structures seen in the adult (ex: Eustachian tube) 4) muscular, postanal tail 3. Earliest chordates were most likely filter feeders 4 . Urochordata and cephalochordata are exclusively marine Urochordata 1. majority are sessile and covered by a fibrous tunic that surrounds the organism and gives the phylum its common name (tunicates) 2. Aka sea squirt because they expel water forcibly from the excurrent siphon 3. Most found in shallow waters 4. Adults are sessile and only show the defining chordate characteristic of pharyngeal basket used for feeding 5. Water enters the incurrent siphon then the pharyngeal slits and out the excurrent siphon Cephalochordata: 1. aka lancelets 2. scaleless, fishlike chordates that are very small 3. all characteristics are apparent in this subphylum 4. shaped blocks of muscle called myomeres enable lancelets to swim Vertebrata: 1. most diverse chordates 2. notochord is usually replaced by a vertebral column of cartilage or bone in the adult
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This test prep was uploaded on 02/12/2008 for the course BIOL 210B taught by Professor Flower during the Spring '07 term at San Diego.

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Chordata Practical - Chordata 1. 3 Subphyla of Chordata: 1)...

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