Coelenterata : General Characters and Example , Multiple Choice questions: NEET


 🌑Coelenterata : Defination 

These are multi cellular aquatic animal with tissue grade level  of organisation having gastro vascular cavity.

🌑General characters

🔴They are aquatic, mostly marine, sessile or free-swimming animals.

🔴They are Diploblastic, Acoelomate, radially symmetrical animal with tissue grade level of organisation.

🔴They are also called as  Cnidaria.The word cnidarian  has  been taken from the Cnidoblasts or cnidocytes. 

🔴Cnidoblasts contain the stinging capsules called as nematocysts which are  present on the tentacles and the body. 

🔴Cnidoblasts are used for the  anchorage, defense and for the capture of prey.

🔴Cnidarians have a central gastro-vascular cavity or Coelenteron with a single opening called mouth on hypostome.

🔴Digestion is extracellular and intracellular. 

🔴Some of the cnidarians are called as corals  because they have a skeleton composed of calcium carbonate

🔴Cnidarians also have  two basic  stage in their life cycle called polyp and medusa

🔴The polyp Is a sessile and cylindrical form like Hydra, Adamsia whereas, the Medusa is umbrella-shaped and free-swimming like Aurelia or jelly fish.

🔴Metagenesis is alternation of generation between polyp and Medusa in cnidarians.  

🔴Polyps reproduce asexually by budding  and form medusae. 

🔴Medusae form sperm and egg sexually and  form the polyps through the Fertilization externally.


🌑Examples of Coelentrata
🔴It is commonly called as Portuguese man of war.
🔴It is marine neuston animal because it always float in ocean.
🔴During floating, it look like a warship therefore it is called as Portuguese man of war.
🔴It has pneumatophore which can be seen on water surface while floating and rest of body are submerged in water.
🔴Pneumatophores are composed of units called zooids which may be gonozooids and gastrozooids. These zooids may  have tentacles.
🌑 Adamsia
🔴It is commonly called as sea anemone.
🔴Body of Adamsia is divided into oral disc, column and pedal disc.
🔴It is found to be attached with molluscan shell by its Pedal disc.
🔴Oral disc has central mouth which is surrounded by the nematocyst bearing small tentacles.
🔴Adamsia and Hermit crab or clown fish show commensalism. Crab get protection from predator due to its stinging capsule.
🔴It is found in United States at North Carolina to Florida in shallow water.

  🌑Pennatula

🔴It is commonly called as sea Pen or Sea feather.

🔴Body  is divided into distal rachis and peduncle.

🔴Rachis has fleshy branches with a series of 8 to 12 gastrozooids.

🔴It is sedentary and colonial animal and found in deep sea and prefer warm water.  

🔴Gastrozooids are feeding zooids and form gamete also Siphonozooids draw water current

🔴It is found in United States at  St. Lawrence to Carolina and also common in Europe.

🌑Gorgonia 

🔴It is commonly called as sea Fan.

🔴It is a salt water invertebrate and can be identified by its purple color tissue and it's fan shape body.

🔴It's skeleton is made up of Collagen derivative compound called as Gorgonin and Calcite.

🔴It is tube like polyp  and protrude from needle like Spicules. 

🔴Gorgonia is sessile , Immobile and Colonial Animal and found to be attached with the surface.

🔴It is found in sea coast of West indies , Atlantic ocean and Madras Coast.

 🌑Meandrina 

🔴It is commonly called as Brain Coral because it's shape resemble with the human brain.

🔴It is a colonial  coelenterate and look like polyp and secrete hard skeleton of calcium carbonate therefore called as stony coral.

🔴They use their tentacles to catch prey and as a defense organ.

🔴Brain Coral reproduce asexually  through buffing of polyp and sexually by sperm and egg .

🔴It is found in shallow warm water in coral reef through out the world like indo Pacific coast and Gulf of Mexico.

 


1. The Coelenterates are mostly marine, aquatic and 

A. Sessile  with asymmetrical 
B. Sessile with radial symmetrical 
C. Sessile with Bilateral Symmetrical 
D. Sessile only  
Answer:  B 

2. The body cavity of Coelenterates  is 
A. Para gastric cavity
B. Spongocoel
C. Gastrovascular cavity
D. Haemocoel 
Answer : C  

3. The term cnidaria is used for the  Coelenterates due to having  

A. Hypostome 
B. Tentacles
C.  Nematocyst 
D. Cnidoblast
Answer:  D 

4. The cnidoblast or cnidocil has a stinging capsule called nematocyst present on 
A. Tentacles and body
B. Body
C. Gastrovascular cavity
D. Tentacles
Answer : A  

5. The term cnidaria is used for the  Coelenterates due to having  

A. Hypostome 
B. Tentacles
C.  Nematocyst 
D. Cnidoblast
Answer:  D 

6. Which of the following is/ are function  of cnidoblast or cnidocil in cnidaria. 
A. Anchorage 
B. Capturing the prey 
C. Defense organ
D. All of the above 
Answer : D  

7. In  Cnidarian,   gastro vascular cavity is present with 

A. Single opening as mouth  on Hypostome 
B. Two opening as mouth and anus on  Tentacles
C. Single opening as mouth on nematocyst 
D. Two opening as mouth and anus on   Cnidoblast
Answer:  A 

8. Meandrina is a Brain Coral and it's skeleton is made up of   
A. Calcium Carbonate 
B. Calcium Chloride
C. Calcium Nitrate 
D. Calcium oxalate 
Answer : A   

9. Which of the following statement is not correct with respect to the cnidaria n.
A. Digestion is intracellular and extracellular .
B. They include coral which release skeleton of calcium carbonate. 
C. Body cavity is paragastric cavity.
D. Obelia has metagenesis in which polyp make alternation with medusa.
Answer : C  

10.  Consider the following statement and select the correct code:

1. Polyp produce Medusa by asexually   whereas Medusa produce polyp by sexual reproduction.
2. Polyp is sessile whereas Medusa is  like umbrella and free swimming . 
A. Only 1                     
B. Only 2
C. Both 1 and  2
D. Neither 1 nor 2 
Answer:  C 

11 . In which of the following Coelenterates, polyp and Medusa make alternation of generation as Metagenesis. 

A. Physalia 
B. Obelia
C. Aurelia 
D. Adamsia
Answer :  B 

12. Which of the following statement is correct.
A. Digestion in Hydra is extracellular or intracellular.
B. Coral has endoskeleton  of Spicules and spongin fibre.
C.  Digestive system of Hydra has two opening. 
D. Polyp is sessile like Hydra and Adamsia whereas Medusa is  like umbrella and  Aurellia. 
Answer : D  

13. Match the list 
A. Pennatula  1. Sea Pen
B. Gorgonia    2. Sea Fen 
C. Adamsia  3. Sea Anemone
D. Physalia  4. Portuguese                                 man of war                  

             A       B       C      D
A.         1        2        3      4
B.         1        2        4      3
C.         2        1        3      4
D.         3        1       4       2
Answer : A   

14. The Brain Coral  is 
A. Fungia
B. Meandrina
C. Gorgonia
D. Aurelia 
Answer : B  



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