6-HOF2 - History of Fishes 2: Jaws Click to edit Master...

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Click to edit Master subtitle style9/14/10History of Fishes 2: JawsLecture 6: Ch. 8; 11 DOF
9/14/10Few surviving jawlessfishes
9/14/10Origin of Jaws:Modification of gill
9/14/10Evolution ofGill arches expand with the lossof first two or three anteriorarchesFirst arch moved forward andbecame the upper and lower jawsSecond gill arch becamehyomandibular providing supportfor jaws
9/14/10Cranialinnervation(trigeminal) isidenticalbetween jawsand visceralarchesEvidence fromgeneexpressionpatterns andontogenysupporthomology of
9/14/10gutcraniummouthEvolution of the jawPrimitive jawless stagegill slitsvisceral cartilages 8-9 arches
9/14/10Stylized GnathostomejawPalatoquadrateMeckel’s cartilageMandibularArch
9/14/10PalatoquadrateMeckel’s cartilageMandibularArchHyomandibularCeratohyalHyoidArchspiracleStylized Gnathostome
9/14/10Diversity of Prey Items;Limitless
9/14/10Diversity of Jaws
9/14/10Jaws, good“perhaps the greatestof all advances invertebrate history wasthe development ofjaws and theconsequent revolutionin the mode of life ofearly fishes” - Romer
9/14/10Why are they good?Gnathostomes versus Jawless Fishes
9/14/10What would theadvantage be to havingThink about it, write it down, share with aneighbor…
9/14/10
9/14/10Greater Feeding Efficiencywith Jaws?Greater bite force?

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Term
Fall
Professor
Chakrabarty
Tags
Evolution, Ichthyology, Jaws, Agnatha, Gnathostomata, Jawless Fishes

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