Chapter 32 & 33 - Continued
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
- Brian
- Enclosed/supported/protected by the Notocord
Pharyngeal gill pouches
- Gill slits
- pharynx
- back of mouth cavity
Post-anal Tail
- Tail extends posterior of the anus