1. WARM UP
List three adaptations that have developed over time in the chordate phylum that have made members of this group effective predators.

2. Hemichordates Notes
Phylum Chordata

3. Origin of Chordates Hypothesis 1: Marine Worms
Embryonic development switches from protostome to deuterostome
Chordate characteristics develop

4. Origin of Chordates Hypothesis 2: Tadpole Larva
Echinoderm larva develops reproductive ability
Larva shape becomes chordate body plan

5. Characteristics of Chordates
Notochord
Solid, rod-like
Movement
Postanal tail
Propulsion
Dorsal nerve cord
Hollow
Pharynx
Gill slits
Feeding and respiration

6. Acorn Worms Deuterostome worms Similar to chordates
“Notochord”
“Gills”
Proboscis, collar, and trunk

7. Tunicates Sessile filter feeders Siphon water Tadpole larva Gill slits
Chordate
Siphon water
Gill slits

8. Lancelets
Chordate features as adults
Filter feeders

9. WRAP UP
How do acorn worms support the hypothesis that chordates developed from marine worms?
How do tunicates and especially lancelets, support the hypothesis that chordates developed from a invertebrate larva with reproductive capabilities?