Derived characteristic define the major clades of chordates
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Hagfishes and lampreys lack hinged jaws
Jawed vertebrates with gills and paired fins include sharks, ray-finned fishes, and lobe-finned fishes.
New fossils discoveries are filling in the gaps of tetrapod evolution.
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Amphibians are tetrapods- vertebrates with two pairs of limb  |  |
 | Reptiles are amniotes- tetrapods with a terrestrially adapted egg,  |
Mammals are amniotes that have hair and produce milk.  |  |
Birds are feathered reptiles with adaptations for flight
