Porifera : General Characters and Examples, Multiple Choice questions: NEET

 

Porifera : Defination 

These are invertebrate primitive multi cellular animal with cellular grade of organisation. 

🌑General characters

🔴Members of this phylum are commonly known as sponges. They are generally marine and mostly asymmetrical animals.

🔴These are primitive multicellular animals and have cellular level of organisation. 

🔴Sponges have a water transport or canal system. 

🔴In canal system Water enters through minute pores called ostia in the body cavity named spongocoel, from where it goes out through the osculum. 

🔴This pathway of water transport is helpful in food gathering, respiratory exchange and removal of waste. 

🔴Choanocytes or collar cells line the spongocoel and the canals. Digestion is intracellular. 

🔴The body is supported by a skeleton made up of spicules or spongin fibres. 

🔴Sexes are not separate i.e. eggs and sperms are produced by the same individual. 

🔴Sponges reproduce asexually by fragmentation   and sexually by formation of gametes. 

🔴Fertilisation is internal and development  is indirect having a larval stage which is morphologically distinct from the adult.

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🔵Extra Shot of Poriferan Character

Archeocytes are totipotent cells in sponges and also called amoebeocytes. Thesocytes are cells in sponge which store food. Parenchymula is larval stage of sponges.

🟡Examples of Porifera 
🟡Sycon
🔴Sycon is  marine and also known as Scypha.
🔴It is found to attach with rock, coral and molluscan shell.
🔴Sycon has exoskeleton made up of spicules therefore it belong to  class calcarea.
🔴Sycon has ascon type of canal system. The path of water current is - Ostia - incurrent canal - Prosopyles - radial canal - apopyles - Spongocoel - osculum.
🔴The length of Sycon varies from 2.5 to 7.6 cm.  They have capability to regenerate their lost body part .


🟡Euspongia 
🔴It is commonly called as Bath sponge because used in clearing tool.
🔴It has exoskeleton made up of sponging fibre therefore it belong to  class Demospongia. Spicules are absent in Euspongia.
🔴It is found in Mediterranean sea as well as American. Sea coast.
🔴Euspongia can reproduce sexually by internal Fertilization with indirect development.
🔴It also reproduce asexually by fragmentation , budding and  regeneration.
🔴 It is globular in shape with numerous osculum mounted as well marked projection in canal.

🟡Spongilla 
🔴It is commonly called as fresh water sponge and atteched with submerged plant, stick etc.
🔴The body colour of spongilla depends on Zoo chlorella which is present as symbiotic partner with spongilla.
🔴The body of spongilla is supported by both Spicules and sponging fibers.
🔴It has a complex leucon type of canal system.The path of water current is - Ostia - incurrent canal - flagellated chamber- Excurrent canal - Spongocoel - osculum.
🔴Spongilla can reproduce sexually by internal Fertilization with indirect development.
🔴It also reproduce asexually by budding and  gemmule formation.
 

1. Consider the following sentences and select the number of  correct statements
1. Poriferan are called as Sponges.
2.  All sponges are  found in marine water.
3. Digestion in sponges are intracellular.
4. Sponges are asymmetrical and primitive multicellular animals.
5. Porifera are Diploblastic with cellular level of organisation.
A. Two           B. Three
C. Four           D. Five
Answer : C  

2. Canal system is unique feature of Porifera that facilitate the path of water
A. Ostia - osculum - spongocoel
B. Ostia - Spongocoel - Osculum
C. Spongocoel - ostia - osculum
D. Spongocoel - osculum - ostia
Answer - B 

3. The minute pore on body of sponge through which water enters from outside called as
A. Choanocytes 
B. Osculum
C. Spongocoel
D. Ostia 
Answer: D 

4. The body cavity of Sponges is 
A. Para gastric cavity
B. Spongocoel
C. Gastrovascular cavity
D. Para gastric cavity and spongocoel
Answer : D 

5. Consider the following function of canal system and select the correct code:
1. Food gathering 
2  Respiratory Exchange
3. Removal of water 
A. 1 and 2
B. 2 and 3
C. 1 and 3
D. 1 ,2 and 3
Answer : D 

6. Which one of the following body parts in sponges are lined by the choanocytes.
A. Spongocoel and osculum 
B. Canals and ostia
C. Osculum and ostia
D. Spongocoel and Canals
Answer : D 

7. Which one the following pairs is not correctly matched.
A. Spongocoel : Para gastric cavity
B. Canal system : Water transport
C. Choanocytes : Collar cells
D. Osculum :  Water Enters
Answer : D 

8. Body of sponges are supported by the exoskeleton  made up of 
A. Spicules  
B . Spongin fibre
C. Both Spicules and spongin fiber
D. Neither Spicules nor spongin fiber
Answer : D 

9. Which one of following features is not associated with members of Sponges.
A. Extracellular and intracellular Digestion
B.  Fertilization takes place inside the body 
C. Sperms and Eggs are produced by the same individual  
D.  Asexual Reproduction by the fragmentation
Answer : A 

10. Which of the following statement is not correct.
A. Larva of Porifera is morphological distinct from the adult.
B. Saxes are Separate.
C. Sexual reproduction takes place by fusion of gamete.
D. Development is indirect.
Answer : B 

11. Match the list 
A. Sycon          1. Scypha
B. Euspongia 2. Bath Sponge
C. Spongilla  3. Fresh water                                sponge

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