Structure of Peripatus and affinity long question for +3 zoology students

STRUCTURE  OF PERIPATUS  AND  AFFINITY

- Peripatus is a soft bodied worm like , bilaterally symetrical animal.

- It shows tracheal mode of respiration.

- It is grouped in phylum arthropoda and class onychophora.

- Class onychophora inclodes primitive (old) worm like arthropods.

- Peripatus connecting like bewteen arhropoda and annelids.

- Peripatus seen in neotropical regions like west indies, america, congo and australia etc.

- It is the terrestrial animal.

- It lives under stones and back ( tree outer layer) of tree and in shady place.

- It is nocturnal in habit. ( night standing animal)

- During day time it remains in the dark place.

- In night time it come out and collect food.

- In feeds on small insects , worms etc. 

EXTERNAL CHARECTER

-It is a soft bodies , worm like animal.

- It grows up to 1 to 2 inc length.

- The soft body shows deep black colour on the dorsal  side.

- The light red colour on the ventral side.

-The skin is soft and bears many minute papillae along the mid dorsal line.

- This papillae produce slime .(mud like) secretion which is protective and help in capturing the food organisms.

Body is divided into two parts,

1. HEAD

 - Head is composed of three segment .

 - It has a pair of antennae.

- Each antennae composed a large number of segments.

- The ventral side of the head mouth is seen.

- The mouth surrounded by a lip.

- A pair of jaws is seen.

- A tongue is also seen in the mouth.

- In head a pair of simple eyes will be seen.

- A pair of oral papillae will be present.

2.TRUNK

- It contains 14-42 segments arragned serially.

- All the segment are alike.

- Anus is present at the posterior end of the body and on the ventral side below genital pore is present.

                            Peripatus is a unipue organism is  connecting like between annelids , arthropods & mollusca.

a.

AFFINITY   WITH  ANNELIDA

- Pressesnce of worm like body with bilateral symmetry.

- Presence of thin flexible cuticle.

- Parapodia like legs.

- Presence of a pair of simple eyes.

- Reproductive tract are ciliated.

- paired nephridia are present.

b. AFFINITY  WITH  ARTHROPODAN

- Presence of a chitinous cuticle.

- Brain is of arthropodan type.

- Salivary gland are modified nephridia.

- Trachial systemof respiration.

- Presence of haemoceal.

- Presence of colour less blood.

- development is like of arthropoda.

c. AFFINITY  WITH  MOLLUSCA

- Slag like appearance.

- Ladder like nervous system.

CONCLUSION

- The onygophora is connecting like between annellid and arthropoda.

- It is not an evolution like between  annellida and arthropoda.

- It is beleved that the present day arthropoda and anygophora originate separetly for a common ansector.

      Prof.- Dr ramakant pradhan 

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