Question

Describe the fate and function of the bones/cartilages of the mandibular and hyoid arches for each of the following Vertebrate taxa:

Agnatha

Chondrichthyes

Osteichthyes

Lissamphibia

Mammalia

Be sure to mention which bones are found each arch and where these bones and there derivatives are found the body of each clade.

Please, please be as descriptive as possible.

Answer 1

In skeletal elements, two primary components provides very important function. They are cartilage and bone with fibrous materials (ligaments and tendons) for support.

These structural materials functions are

• To support the mass of the body and all of the muscles and organs that are part of the body
• To remain strong under the stresses of locomotion
• To be strong at the junction where two bones meet.
• To protect against impact to soft tissues, such as the skull protects the brain

Firstly, see what is Cartilages, bone, Hyoid bone and Mandibular bone.

Cartilage:

It is defined as a firm but elastic skeletal tissue whose matrix contains chondroitin sulfate and elastic protein (fibers) molecules that bind with water.

There are different types of Cartilages. They are

• Hyaline cartilage-found primarily on the ends of ribs and on the trachea
• Elastic cartilage - found primarily on external ear and epiglottis
• Fibrocartilage - found in the intervertebral disks and pubic symphysis
• Calcified cartilage - found in the vertebrae of cartilaginous fish

Bone:

Bone is a composite tissue similar to cartilage, but have mineral component, It primarily consisting of calcium

According to Encyclopaedia Britannica,

Hiayoid bone are

• U-shaped bone situated at the root of the tongue in the front of the neck ,
• between the lower jaw and the largest cartilage of the larynx, or voice box.
• The primary function of the hyoid bone is to serve as an anchoring structure for the tongue. It has no articulation with other bone Mandibular bone is the jaw in vertebrates that is hinged to open the mouth

The Bones/Cartilages of the madibular and hyoid arches of the each vertibrates are follows:

1.In First Agnatha

There is no internal bony skeleton instead it have thick bony plates and scales that cover the body.

These scales provide three advantages

• phosphate reserves
• to stiffen and allow the body two maintain its shape as size increases.
• protection against predation and abrasion as moved along the substrate.

1.1 Later Agnatha,

As the jawless fish evolved, they became

• More streamlined with dorsoventrally flattened heads, and could probably move rapidly under the surface of the water.
• To aid in balance while moving rapidly in this way, these fish had a dorsal bony spine and the tail was longer on its ventral surface than on its dorsal surface
• Headshields became elborate and sometimes hydrodynamically wing shaped.

2. Chonodrichthyes:

Sharks, skates, and rays comes under this class. These are cartilaginous fishes.

Members of the Chondrichthyes all lack true bone and have a skeleton made of cartilage. Only their teeth, and sometimes their vertebrae, are calcified.

Body covered with placoid scales in mouth and used as teeth.

3. Osteichthyes:

There are more species of bony fish than any other group of vertebrates.

These fish have a bony skeleton and an operculum or flap covering the gill opening.

The jaws become more complex and capable of extensible movement.

4.The Lissamphibia:

Lissamphibians consist of three living groups: the Salientia (frogs), the Caudata (salamanders), and the Gymnophiona.

pedicellate teeth, bicuspid or multicuspid, with basal uncalcified zones; spool-shaped vertebrae

5.Mammalia:

In many mammals Hyoid bones are present. It allows a wider range of tongue, pharyngeal and laryngeal movements by bracing these structures alongside each other in order to produce variation.

The hyoid bone is important to a number of physiological functions, including breathing, swallowing and speech. It is also thought to play a key role in keeping the upper airway open during sleep.