[BIOL 3114] - Final Exam Guide - Everything you need to know! (67 pages long)
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OSU
BIOL 3114
FINAL EXAM
STUDY GUIDE
Vertebrate Morphology
Chapter 3
Earliest fossils
Early chordates ~520 mya form China
Hailouella – sister group to vertebrates?
o Notochord, myomeres, pharynx
Derived traits – brain, eyes muscular pharynx, but no evidence of cranium
Myllokunmingia and Hailouichthys – small (3 cm)
o ~520 mya in China
o Cranium, W-shaped myomeres
o Dorsal fin
Primitive Vertebrates
Earliest vertebrates lacked:
o Jaws
o Paired fins
o Mineralized tissues
Primitive living verts share plesiomorphies
Class Agnatha – paraphyletic
o Hagfish – class Myxinoidea
o Lamprey – class Petromyzontoidea
Hagfish
~40 species
50 cm long
Soft, pinkish/purplish skin, no scales
Mouth with no jaws, 6 tentacles
Keratin tooth plates and protusible tongue
1-15 external gill openings
Notochord, no vertebrae
Degenerate eyes covered by skin
Single, terminal nostril
Accessory hearts near liver and tail
Single, semi-circular canal
No bone
Food travels through digestive tract in mucus sac
Simple kidney, isosmotic body fluids
Numerous mucus glands – defense
Ties self in knot to feed and sneezes to clean off mucus
Scavengers
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