1 - Lecture 33 Notes

Remains postanal tail regresses remnant seen as tail

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Unformatted text preview: otochord postanal tail Chordate features Notochord Dorsal hollow nerve cord Postanal tail Pharyngeal slits •  openings between the pharynx and the exterior •  associated with filter feeding or respira*on dorsal hollow nerve notochord pharyngeal slits postanal tail Chordate features In adult humans: Notochord – part of the vertebral column Dorsal hollow nerve cord  ­ remains Postanal tail – regresses, remnant seen as tail bone (coccyx) Pharyngeal slits – only one pair remains and forms the Eustachian tube dorsal hollow nerve notochord pharyngeal slits postanal tail Chordate features Three synapomorphies dorsal hollow nerve notochord pharyngeal slits postanal tail Clicker ques*on... Why are pharyngeal slits not considered a synapomorphy of chordates? a. Because they do not occur in all chordates. b. Because they evolved convergently in hemichordates and cephalochordates. c. Because they have been further modified within the chordates. d. Because they occur in other deuterostomes. = pharyngeal slits pharyngeal slits Chordates include two no...
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This document was uploaded on 06/25/2013.

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