Bio Lab Wksht & HW Questions 97

Bio Lab Wksht & HW Questions 97 - the other. This...

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92 Examine a whole mount of Amphioxis using transmitted light on a dissecting microscope, and/or using the scanning objective on your compound microscope. Note that the animal tapers at both ends, but that the posterior end is more pointed. Label the diagram below as you read through the following description. Figure 1. Amphioxis whole mount, lateral view (Subphylum Cephalochordata) The mouth, which is located at the anterior end of the body, is surrounded by tentacles. The mouth opens into the cavity of the pharynx , which is enclosed by numerous gill bars ; the openings between the gill bars are the pharyngeal gill slits . Dorsal to the pharynx and darkly stained intestine is a rodlike structure that extends from one end of the body to
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Unformatted text preview: the other. This is the supporting notochord . Immediately dorsal to the notochord is the hollow, dorsal nerve cord. Examine a cross section of Amphioxis made in the region of the pharynx, and correlate it with the anatomy you observed in the whole mount. Water enters the mouth, moves into the pharynx, and exits through the gill slits. As it moves across the gill slits, food is trapped and gases are exchanged. The food particles then enter the intestine and water exits through the atriopore (not visible in cross section). Ventro-lateral gonads may or may not be visible in your section. Label the diagram. Which chordate character is missing? Figure 2. Amphioxis cross section (Subphylum Cephalochordata)....
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This note was uploaded on 12/27/2011 for the course BSC 1020 taught by Professor Danmoon during the Fall '11 term at UNF.

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