A brief introduction to chordates

1. Unit I: Introduction to Chordates
Topic: General Characteristics
B.Sc Zoology 3rd semester

2. What are Chordates?
• Chordates are those animals which have a
stiff, supporting rod like structure or chord
along the back, the notochord which is found
in all members of the phylum at some stage of
their lives.

3. Three Fundamental Chordate
Characters:
1. Notochord
2. Dorsal tubular nerve chord
3. Pharyngeal gill slits

5. General characters of phylum
chordata:
1. Chordates are aquatic, aerial or terrestrial. All are free living with
no fully parasitic forms.
2. Body small to large, bilaterally symetrical and metamerically
segmented.
3. A postanal tail usually projects beyond the anus at some stage of
life and may or may not persist in the adult.
4. Exoskeleton often present, well developed in most vertebrates.
5. Body wall triplobalstic.
6. Coelomate animals.

6. 7. Notochord is always essentially present at some stage of life
cycle.
8. A cartilaginous or bony, living and jointed endoskeleton
present in the majority of members.
9. Paired pharyngeal gill-slits are present.
10. Digestive system is complete with digestive glands.
11. Blood vascular system is closed.
12. Excretory system comprising proto-meso-metanephric
kidneys.
13. Nerve cord is dorsal and tubular. Anterior end usually
enlagged to form brain.
14. Sexes are separate.

8. • Tornaria larva