General Characters, Examples of Phylum Cyclostomata , Multiple Choice questions: NEET

 


🌑Defination 

🔴Cyclostomata are primitive vertebrates and having circular mouth 👄 but absence of jaws.

🌑General Characters 

🔴All members of cyclostomes are ectoparasite on some fish 🐟.

🔴They have elongated body with six to fifteen pairs of gills slits for  respiration 🫁.

🔴They have circular and sucking mouth  👄 without jaw.

🔴Body is not covered by the scales ♎ and paired fins are absent.

🔴Notochord is replaced by the cartilaginous vertebral column. Cranium is also cartilaginous.

🔴Heart has two chambers and circulatory  system is closed type.



🔴Animals are marine but migrated into fresh water for spawning. After spawning they die after few days and their larva return to ocean after metamorphosis.

🔵Extra shot of general character 

🔴Mouth bear teeth and moved by protractor and retractor muscles.

🔴Digestive system has no stomach and oesophagus is directly open into intestine.

🔴Brain is well developed with 10 pair of cranial nerve.

🔴A pair of mesonephric kidney are present for the Excretion.

🔴Life cycle of cyclostomes have Ammocoeate larva which is transformed in to adult after metamorphosis.

🌑Example of Cyclostomata 

🔵Petromyzon

🔴It is commonly called as lamprey.

🔴Body is elongated. Mouth is circular and sucking with large and sharp teeth.

🔴Skin is soft, smooth without scales but  has with unicellular mucus gland on skin.


🔴It has no paired fin but a median fin is present.

🔴It has six to fifteen pairs of gills slits for respiration.

🔴Lamprey are ectoparasite on some large fish.

🔴It is migrated into fresh water for spawning. After spawning they die after few days .

🔴Vertebral column and  Cranium is cartilaginous.

🔴Circulatory system is closed.

🔴It is commonly called as Hag fish and exclusively marine.

🔴Body is elongated. Mouth  terminal , circular and sucking without eyes and jaws.

🔴Hagfish release slime which affect respiratory system of their predator.

🔴It has no dorsal  fin or reduced dorsal fin.

🔴It has six to fifteen pairs of gills slits for respiration on both side of body.

🔴Hag fish has primitive brain and reduced pineal body.

🔴It is migrated into fresh water for spawning. After spawning they die after few days .

🔴Vertebral column and  Cranium is cartilaginous.

🔴Circulatory system is closed.


1. Cyclostomes are:  
A. Endoparasites on most of fish
B. Ectoparasites on most of fish
C.Endoparasites on some  fish 
D.Ectoparasites on some fish  
Answer: D  

2. Which one of the following is not a character of Cyclostomata.
A. Upper and lower jaw.
B. Elongated body.
C. Scale less body
D. Circular and sucking mouth
Answer: A   

3. How many pairs  of gill slits are present on Cyclostomata for respiration.
A. 8 to 10 pairs 
B. 6 to 15 pairs
C. 10 to 20 pairs
D. 12 to 24 pairs
Answer: B 

4. Which one of the following statement is incorrect for the Cyclostomata
A. They have eel like elongated body.
B. They have circular and sucking mouth.
C. Scales and paired fins are absent.
D. Cranium and vertebral column is cartilaginous.
Answer : C 

5. Which one of the following pair is incorrect for the Cyclostomata.
A. Mouth : Circular and sucking 
B. Vertebral column : Bony
C.Skin : Smooth without scales
D. Circulatory system: closed type.
Answer: B 

6.Cyclostomes are Agnatha , signifies
A. Elongated body
B. Sucking mouth 
C. Absence of jaw
D. Scale less body
Answer: C 

7. Myxine is
A. Cuttle fish. B. Jelly fish
C. Dog fish.   D. Hag fish
Answer: D 

8. Which of the following statement is not correct for the Cyclostomata.
A. They are marine but migrated into fresh water for spawning.
B. After few days of spawning they die.
C.Their larva are remain survive   into fresh water without metamorphosis .
D. Their larva after metamorphosis return to ocean.
Answer: C 

9. Petromyzon is
A. Cuttle fish. B. Jelly fish
C. Dog fish.   D. Hag fish
Answer: D 

10. Given below is a Diagram of petromyzon. Identify the organ denoted by letter A 



A. Tympanum.   B. Nostril
C. Gills slits.       D. Eye spot
Answer: C 



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