Phylum Chordata (backbones?)
1. hollow nerve cord
2. notochord
3. pharyngeal pouches – paired structures in the thought that become gills in fish or ear bones in humans (among other things)
4. tail
Chordates without backbones
1. lancelets + tunicates
– 550 mya and they have all four characteristics at one time in their lives
Fish
1. first vertebrate – 510 mya
2. first were armored and jawless
– eventually developed jaws for eating and defense
3. characteristics
– scales, paried fins for control, lateral line to sense water pressure
4. reproduction
– external or internal
– eggs outside the mother, eggs inside the mother, live developing young in the mother
There is an assignment in google classroom for you to finish.
I think that in class you explain things better and it has better quality.
The Video i mean