1. Phyla Hemicordata and Chordata
BIO 2215
Oklahoma City Community College
Dennis Anderson

2. Fig. 23.2b

3. Phylum Hemichordata Three body regions Deuterostome Gill slits
Proboscis
Collar
Trunk
Deuterostome
Gill slits
Open circulatory system
Dorsal and ventral nerve cord

4. Fig a

5. Fig b

6. Chordates
Fig. 23.2a

7. Phylum Chordata
Fig. 23.1

8. Phylum Chordata Notochord Gill slits or pharyngeal pouches
Dorsal hollow nerve cord
Postanal tail
Segmented muscles
Deuterostome

9. Fig. 23.p469a

10. Fig. 23.p469b

11. Fig. 23.p472a

12. Fig. 23.p472c

13. Evolutionary Adaptations of Chordates
From filter feeding ancestors to active predators
Mobility
Oxygen capture
Digestion
Circulation
Nervous system

14. Skeletal Changes Skeleton becomes stronger to work with bigger muscles
Allows more rapid movement
Fig. 23.p477

15. Oxygen Capture
Gill slit and muscular pharynx will move more water over gills
More oxygen is extracted from water
Fig. 23.p478a

16. Circulation
Stronger heart to circulate blood faster
Fig. 23.p478a

17. Digestion Digest more food Muscularized gut Digestive glands Liver
Pancreas
Fig. 23.p478a

18. Nervous System More complex for better
Motor control of body to capture food
Sensory detection of the animals environment
Integration centers (brain)
Fig. 23.p478b

19. Brain With Three Parts
Hindbrain
Midbrain
Forebrain
Fig

20. Chordate Subphyla Subphylum. Urochordata Subphylum. Cephalochordata
Phylum. Chordata
Subphylum. Urochordata
Subphylum. Cephalochordata
Subphylum. Vertebrata

21. Sea Squirts

22. Subphylum Urochordata
Sea squirts
Gill slits (pharyngeal slits)
Notochord
Only in larva
Adult has tunic

23. Fig. 23.5

25. Fig. 23.7

26. Amphioxus
Fig. 23.CO

27. Subphylum Cephalochordata
Amphioxus
Notochord length of body
Dorsal hollow nerve cord
Gill slits
Segmented muscles

28. Amphioxus

29. The End