Question

The tympanum (ear drum) is absent in
A) Rays
B) Cartilaginous fishes
C) Bony fishes
D) All of the above

Answer 1

Hint: Tympanum is the ear cavity of some animals. It is a thin membrane sheet that separates the outer ear and middle ear in humans. TMP stands for tympanic membrane perforation, it is a condition of rupture or perforation of eardrum. It is oval in shape and semitransparent. It is a pearly grey trilaminar membrane and separates the middle ear from outer ear..

Complete answer:
Ear is an organ of hearing. There are three parts of ear: external ear, middle ear, internal ear for humans. Middle ear is known as a tympanic cavity. External ear has an auricle, external auditory canal. Middle ear has a tympanic membrane, middle ear cavity, auditory ossicles, and an Eustachian tube. Inner ear has an oval window, round window, cochlea, and semicircular canals.

Tympanic membrane has three layers
>Outer cuticular layer (keratinised, hairless, devoid of dermal papillae)
>Intermediate fibrous layer (outer radiating, inner circular fibers)
>Inner mucous layer (simple columnar or squamous)

Tympanum is responsible for passing sound from the air to the ossicles inside the middle ear. It is seen as vertebrates except Pisces. Fishes can hear, but ears are inside of fishes. Bony fishes detect any vibration through their ears tones, that is known as otoliths.

Thus, the correct answer is option (D).

Note:Vertebrates are the animals with backbone or vertebral column. There are five groups of vertebrate animals: mammals, birds, reptiles, amphibians, fish. Pisces fishes is that whole body of fish is covered with a tough, scaly, skin, which extends over the eye and contains pigments and sometimes slime glands.