Chordates and fish!

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.