The chordate groups consists of two invertebrate

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The chordate groups consists of two invertebrate subphyla x Urochordata tunicates x Cephalochordata lancelets (amphioxous, Branchiostoma ) And one vertebrate subphyla Vertebrata , broken into two superclasses x Agnatha lampreys, hagfishes x Gnathostomata six classes o Chondrichthyes sharks, skates, rays o Osteichthyes bony fish o Amphibia frogs, toads, salamander, sirens o Reptilia snakes, lizards, turtles, tortoises o Aves birds o Mammalia mammals, including monotremes (platypus), marsupials (opossum), and placental mammals (marine mammals, humans, dogs) Procedure 1. Examine representative chordates 2. Examine the model of amphioxus ( Branchiostoma ). Identify the rostrum , tentacles , oral hood , mouth , dorsal , ventral and caudal fins , notochord , nerve cord , gill slit , atrium , stomach , atriopore , and anus What part of their body structure indicates these animals are filter feeders?
Exercise 7 Animals Lake-Sumter State College, Leesburg Laboratory Manual for BSC 1011C 80 Are there indications of cephalization? If so, what are they? 3. Under the direction of your instructor, dissect and examine a bullfrog (Appendix IV) What is the function of the frog’s tympanum? The glottis? What purpose do the nares serve? Contrast the way a frog moves on land with the way it moves in water. Trace the path of food in the digestive tract from the mouth to the cloca. What does the word cloaca mean and what three body systems empty into it? Explain the term urogenital system. 4. Under the direction of your instructor, dissect and examine a dogfish (Appendix V) What is the purpose of the ampullae of Lorezini? How do they work? How is their location in the body of the shark a reflection of what they do?
Exercise 7 Animals Lake-Sumter State College, Leesburg Laboratory Manual for BSC 1011C 81 How does the spiral valve aid in nutrient absorption? What is the purpose of the rectal gland? How does this organ allow for some species of chondrichthyians to survive in a variety of salinities? How many external gill slits does a dogfish have? Is this common among sharks? What is the purpose of the spiracles and what does their presence in this species say about its lifestyle? Trace the path of blood flow through the circulatory system staring with the heart.
Exercise 7 Animals Lake-Sumter State College, Leesburg Laboratory Manual for BSC 1011C 82 Review Questions 1. List two advantages organisms with a coelom possess. 2. Compare and contrast prostomes and deuterstomes. 3. What are the general characteristics of all molluscs? 4. Externally, arthropods have specialized parts or segments (tagmata). Explain how this is different when compared to annelids.
Exercise 7 Animals Lake-Sumter State College, Leesburg Laboratory Manual for BSC 1011C 83 5. For each, give examples of animals with the following characteristics: a. closed circulatory system b. cephalization c. respiratory organ d. brain and nerve cord e. jointed appendages f. exoskeleton 6. Compare echinoderms and chordates as it pertains to symmetry and segmentation.

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