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Chapter 34
Four Critical Innovations of Chordata Body Design
Notochord
Dorsal, hollow nerve cord
Pharyngeal gill pouches
Post-anal tail
These four features are exhibited at some point of life history/development
Only some Fishes exhibit all four
Notochord
Cartilagenous supporting rod along the dorsal axis
Replaced by jointed "backbone"
Vertebral column of hardened cartilage or bone
Dorsal, hollow nerve cord
Expanded at the anterior end
Enclosed/supported/protected by the Notocord
Pharyngeal gill pouches
Post-anal Tail
Tail extends posterior of the anus
Humans