VISION IN ARTHROPADA in easy type in biology subject in graduation students zoology paper

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VISION  IN ARTHROPODS
Arthropods eyes are simple as well as compound eyes.
-that means insects are both types of eyes are considered to be most succssful animal an earth.
A. THE COMPUNUD EYES
-A pair of compound eyes for vision that seen in crabs, shrips, barnacles, water fleas etc.
-In compound eyes , 2 eyes is composed of a large number of independent visual unit called ommatida
-Ommatidia are connected to the optic nervs.

-Ommatidia are 2 types,
a.    Dioptrical region: Receiving and focusing light rays.
b.    Inner sensory region: Receiving light and sending the nerve impulse to the brain.
-   Sensory region analyses the impulse as image of the object.
- Compound eye is incapable of giving distance vision but it capable to 3600 view.
- It is a large globular and a movable stalk.
- Each ommatidium is capable of producing image of a small part of the object seen and not the entair object.
- All small image combined in the brain to form a comlete image of the object,this vision is called as mosic vision.
- Hence a single ommatidium can not perecive entair object.
- The compound is its high flicker fusion rate is about 50 fps as compair to 12-15 fps of human eyes.
THE APPOSITE IMAGE : This type of vision occurs in bright light.
THE SUPERPOSITION IMAGE :This type of vision occurs in dim light.

CHARECTERISTING THE COMPOUND EYES
- The compound eyes helps the animal in detecting the movement of the predators and escape before catch on strike.
B. THE SIMPLE EYE
1.        The simple eye is 2 types,
1.The median indirect eyes
- This are large convex and covered with thick cuticle that froms lens.
- The sensory rahabdoms point backwords towords the reflecting layer called Tapetum.
- The rhabdoms are surrounded by many sensory ratinal calls which transmit nerve imples to the optic nervs and then to the brain.
-  This eyes are used for vision in the night or dim light.
2.The lateral direct eyes
-  Lateral eyes are small in size , 3 pairs and located on the lateral sides of prosoma.
- This eyes are covered externaly by a biconvex lens formed from cuticle.
- Tapetum is absent in these eyes.
- The each rhabdome is connected to a sensory retinal cell, that is connected to the nerve.
- The lateral eyes are vision in daytime or in bright light.
THE INSECT OCELLI
- Ocelli are simple eye, more or less similar to the simple eyes of arachnids (8 foot animal).
- It provide the eye with distant vission .
- Ocelli are also give night vision to night flying insect.
Hence the insects enjoy both type of vision , namely detection of movement with compound eyes and distant vision with simple eye or ocelli.

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 Prof.- Dr ramakant pradhan 
best of luck for your exam , you study and ask u doubt or other wise dout in other long question in biology ask me in comment box .ok  student by . 

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