EEB267H1 Midterm: Lab exam
9 Apr 2018
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Lab one: basal chordata: cephalochordata: (lancelets, amphioxus, elongated cirri, dorsal nerve cord, pharyngeal slits, post anal tail, urochordata: (tunicates) Ascidiacea- free swimming, non-feeding larvae, metamorphosis into sessile filter feeding adults. Use mucous lined pharyngeal slits to trap food (filter feeding: notochord and tail absorbed, dorsal hollow nerve cord reduced to 2 small clusters, increased number of paired pharyngeal slits, syphon twists to prevent sucking up sand. Cyclostomata: jawless, round mouth fish with keratinized tooth plates. 12 gill pores on each side of the head. 7 gill pores on each side of the head. No true fins, but do have a dorsal fin. No paired fins, 2 dorsal fins, symmetric caudal fin. 2 pectoral fins, long and skinny dorsal and ventral fin that connects to caudal fin. Single olfactory organ, tentacles around mouth, simple eyespots. True eel vs. dipnoi: lungfish always has anal fins (may be reduced), also more apparent, large scales. True eel: gymnophiona has costal grooves, lacks obvious tentacles.
