1. Phylum Chordata
A.K.A. Chordates

2. Chordate Cladogram

3. Four Distinguishing Features
Single, hollow, dorsal nerve cord
Gill or pharyngeal slits (or pouches)--small openings along anterior part of body or pharynx
Notochord: flexible rod for support that lies between the nerve cord and gut
Post-anal tail: tail that extends beyond the anus

4. Nerve Cord Runs along the dorsal or back side of a chordate
Connects nerves to internal organs, muscles and sense organs

5. Notochord
A long supporting rod located just below the nerve cord (ventral to the nerve cord)
All chordates begin life with the notochord, but do not always retain it when they reach adulthood (like the human post-anal tail)
Notochord is usually replaced with backbone in most vertebrates

6. Pharyngeal Pouch
Series of paired structures that develop into gills in some vertebrates like lancelets and tunicates (and fish too)
In humans they develop into the internal ear organs and some throat organs like the parathyroid

7. Chordate characteristics

8. Subphylum Urochordata A.K.A. tunicates
SEA SQUIRTS
3,000 species; all marine
Invertebrates
Sessile
Filter feeders
Larval form has all four characteristics of chordates; adults do not

9. Subphylum Urochordata A.K.A. tunicates
SALPS
Planktonic
Filter feeders
Warm water
Invertebrates

10. Subphylum Cephalochordata A.K.A. Lancelets (amphioxis)
23 species
7 cm long, similar in shape to a fish
Retains chordate characteristics entire life
Invertebrate (lack a backbone)
Filter feeders using its pharynx with pharyngeal slits; inhabit soft bottoms

11. Subphylum Vertebrata A.K.A. Vertebrates
Have a backbone; usually made of bony segments called vertebrae
Bilateral symmetry
Endoskeleton
Complete digestive system
Closed circulatory system
96% of all chordates are in this phylum
Include: fish, reptiles, birds and mammals