HHMI on "500 million year old brain" from cephalochordate, which is probably a 100 million year old brain from cephalochordate.
https://youtu.be/bN-8oYVilps
TED Ed video on sense of smell
https://youtu.be/snJnO6OpjCs
TED Ed video on eye
https://youtu.be/OGqAM2Mykng
Video on neurulation
https://youtu.be/vvBBFOu9h1w
Linda Holland video 1
https://youtu.be/K2iLCHZptz4
Linda Holland video 2
https://youtu.be/oGAtylErrLQ
Vertebrate diversity video: Fish
https://youtu.be/fNlQzE5QVoo
Debate on vertebrate origins
https://youtu.be/XrHrjTDn-tY