Question

Ommatidia serve the purpose of photoreception in
A. Cockroach
B. Frog
C. Humans
D. Sunflower

Answer 1

Hint: Arthropods include all the insects’. As it is divided into three segmented bodies; head, thorax, and abdomen. They are found in every type of habitat, even in houses. They have also divided into many species with different scientific names.

Complete Answer:
- The body of arthropods is divided into; head, thorax, and abdomen segments. The cockroaches have a long pair of antennae that involve in the vibrations and smelling things.
- The antennae are connected with the head and also include the mouth part for chewing and scraping of food and compound eyes. Their eyes are light sensitive and have poor vision and the mouth shows side to side movement so it is capable of processing taste and smell at the same time.
- Now, this compound eye consists of a number of ommatidia each forming a separating image that is further combined by the brain to form the complete image, this type of vision is considered as mosaic vision and are found in cockroaches.

Thus the correct option is ‘A’. Cockroach.

Additional information:
- Cockroaches have salivary glands and esophagus that are involved in the digestion process. Then the thorax part includes three pair legs and two pairs of wings.
- The head consists of a plate-like structure behind it that is named as a pronotum, it is important as it is the marking to differentiate between other arthropods. Now comes the abdomen part, it comprises reproductive organs also.
- In the back, there are two short protrusions termed as cerci, they involve in rearing of antennae and also connected to the roach’s legs with the nerve ganglia in the abdomen. This helps their locomotion process to start while there is any sense of vibration.
- Inside the body of a cockroach there is a white substance that is the fat bodies just like the humans have. This helps in the store of energy after the break-down of food.

Note: The cockroaches can be mistaken for other arthropods like, grasshoppers, beetles or crickets. Remember the cockroach has a flattened broad body with long hind legs and a pair of antennae. But beetles and crickets have narrow body structure compared to roaches.