Phylum: Aschelminthes : General features and Example , Multiple Choice questions: NEET

🌑Defination of Aschelminthes

Aschelminthes are  Pseudocoelomate , Triploblastic, bilateral symmetrical roud worms with  organ level of organisation . 

🌑General features 

🔴The body of the aschelminthes is circular in cross-section, hence, the name roundworm. 

🔴They may be freeliving, aquatic and terrestrial or parasitic in plants and animals. 

🔴Roundworms have organ-system level of body organisation. 

🔴They are bilaterally symmetrical, triploblastic and pseudocoelomate animals. 

🔴Alimentary canal is complete with a well- developed muscular pharynx. 

🔴An excretory tube removes body wastes from the body cavity through the excretory pore. 

🔴Sexes are separate (dioecious), i.e., males and females are distinct. Often females are longer than males.

🔴Fertilisation is internal and development may be direct or indirect. the young ones resemble the adult. 

🔴Body of Round worms are covered by the syncytial cuticle to protect the body from digestive enzyme in body of host.

🔴They have  nervous system including nerve ring around the Oesophagus and branches nerves through out the body.

🔴Respiratory system is absent . They Respire through their body surface.

🌑Examples of Platyhelminthes  

🟡 Ascaris 

🔴Ascaris is long round worm which can be up to more than 30 cm but female is always longer than male. 

🔴 Ascaris show sexual dimorphism. Male is usually shorter with folded end at one side.

🔴Ascaris has non cellular cuticle covering on body to get protection from digestive enzyme of host.

🔴Digestive system is well developed in with various digestive organs.

🔴Nervous system include nerve ring with numerous nerve cords.

🔴 Embryonated egg is infective stage of Ascaris. These eggs are passed out with the stool of infective person and make contaminated the soil.

🔴Egg is ingested by host when it comes contact with contaminated soil into host body. 

🔴Egg is developed into Rhabditiform larva and than into adult Ascaris.

🟡Wuchereria 

🔴It is commonly called as Filaria worm.

🔴It show sexual dimorphism. Adult female is usually longer  with rounded  ends and male is shorter than female. The tail of male is centrally curved.

🔴Wuchereria has 15 pairs of sensory organs.

🔴It resides in lymphatic system of Human but may also found in blood.

🔴Alimentary canal include Muscular pharynx oesophagus intestine and anus. The mouth is present without oral lips.

🔴Female genital pore is present as vulva whereas male has cloaca.

🔴Penial setae or copulatory Spicules are present in male.

🔴Microfilareae is larval stage of wuchereria found in blood of human.

🟡Ancylostoma

🔴It is commonly called as Hook worm.

🔴Adult female is usually longer  with rounded  ends and male is shorter than female.

🔴Hook worm is small cylinder and white or pinkish in color.

🟡It has sharp teeth or cutting plate in their buccal capsule.

🔴Male Hook worm has bursa with two Spicules.

🔴Female Hook worm has vulva. It lay 10000 to 30000 eggs per day.

🔴It create various health complex like anemia , Malnutrition and protein loss.

 

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

1.  Members of Aschelminthes have dorso flattened body.  

2. Members of Platyhelminthes have round body in cross section area. fl

A. Only 1   

B. Only 2

C. Neither 1 nor 2 

D. Both 1 and 2 

Answer : C  

2. Which of the following pairs of feature are present in members of Aschelminthes.

A. Organ system level of organisation and Pseudocoelom.

B. Acoelomate condition and Radial symmetry

C. Flame cells and Protonephredia. 

D. Diploblastic condition and Coelomate

Answer : A  

3. Alimentary canal of round worm is complete with well developed 

A. Radula  

B. Muscular Pharynx 

C. Gastric Caecae 

D. Syrinx 

Answer : B  

4. Which one of following is Excretory organ in members of Aschelminthes.

A. Malpighian tubules  

B. Flame cells

C. Protonepheredia 

D. Excretory pore 

Answer : D 

5. Which of the following statement is not correct with respect to Aschelminthes.

A. Development is direct or indirect  

B. Larva resemble with the adult.

C. Fertilization is external.

D. Saxes are Separate. 

Answer : C  

6. Which of the following statement is correct for the round worms.

A. Alimentary canal is incomplete.

B. They remove their nitrogenous waste through body surface.

C. Fertilization is external.

D. Saxes are Separate 

Answer : B  

7. Match the list 

A. Enterobius  1. Pin worm

B. Ascaris       2.Round worm 

C.Wucheteria 3.Filaria worm                     

D.Ancyclostoma 4.Hook                                          worm                                              

             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  

8. Which of the following statement is correct with respect to round worm.

A. Development is indirect without larval stage.

B. Female individual is often longer than male.

C. Fertilization is external.

D. They are mostly hermaphrodite. 

Answer : B  

9. Consider the following characteristics of Aschelminthes and select the correct code:

1. Aquatic 

2. Terrestrial 

3. Free living

4. Parasite in animals 

5. Parasite in Plants

A. 1, 2, 3 and 4

B. 1, 2, 3 and 5

C. 2, 3, 4 and 5

D. 1,2,3,4 and 5

Answer : D 

10. In which of the following animals, mesoderm is present as scattered pouches In between the ectoderm and endoderm.

A. Round worm

B. Flat worm

C. Earth worm

D. All of the above.

Answer : A