Lecture 3

Question 1

What are cyclostomes?

Answer 1

Hagfish and Lampreys

cyclostomes means round mouths

Question 2

Give some diagnostic features of hagfish

Answer 2

No elaborate skull
1 or 2 comment external gill pores
1 semicircular canal
No dorsal fin
Adult heart without nervous system 
Atrium and ventricle not closely set 
Blood isotonic with water

Question 3

Give some diagnostic features of lampreys

Answer 3

Slightly elaborate skulls 
Single dorsal nostril atop the head 
7 pairs of separated external gill slits
2 semicircular canals 
Extrinsic eye muscles 
Simple vertebrate 
Anterior and posterior dorsal fins

Question 4

Features lampreys and jawed vertebrates share

Answer 4

Vertebrae
Elaborate skulls
Extrinsic eye muscles 
Closely set atrium and ventricle 
At least 2 semicircular canals 
Neuromasts

Question 5

What are the functions of vertebrae?

Answer 5

Support
Protection
Movement
Mineral storage