Question

Characteristics of chorades and Mammals ?

Answer 1

Characteristics of Chorades

in the animal phylum Chordates have four main characteristics-

1. A Notochord
2. A dorsal hollow nerve cord
3. Pharyngeal slits
4. Post-anal tail

Notochord

In the chordates notochord is a flexible, rod-shaped structure that is found in the chordates embryonic stage and also in the adult stage of some species.

Dorsal Hollow Nerve Cord

The dorsal hollow nerve cord originates from ectoderm which rolls into a hollow tube at the time of development. In it, it is located dorsally to the notochord. The nerve cord found in most chordate embryo improves into the brain and spinal cord, which contain the central nervous system.

Pharyngeal Slits

Pharyngeal slit is open in the pharynx which extend to the outside environment. In aquatic organism pharyngeal slits allow for the exit of water which enters the mouth during feeding.

Post-anal Tail

The post-anal tail is following elongation of the body which extending further than anus. The tail contains skeletal element and muscle, that deliver a source of locomotion in aquatic species.

Characteristics of mammals

1- Hair and Fur

All mammals have hairs from some parts of their bodies through at least specific stages of their life cycles. Mammalian hair could take on some different forms, including thick fur, defensive quills, long whiskers, and even horns. Hair serves many functions like protection for delicate skin, insulation against the cold, camouflage against predators, and sensory feedback.

2- Mammary Glands                                         

mammals care for their young with milk produced by the mammary glands.

3- Single-Boned Lower Jaws

The mammals lower jawbone is composed of a single piece which attach directly to the skull. This bone is known as the dentary, it hold the teeth of the lower jaw.

4- Three Bones in the Middle Ear

Mammals have three inner ear bones—the incus, the malleus and the stapes, they are commonly stated to as the hammer, anvil and the stirrup—which makes unique to mammals.

5- Diaphragm

the mammals diaphragms are more advanced than birds, and reptiles. this means is that mammals can breathe and utilize oxygen more efficiently than other vertebrates .

6- Four-Chambered Hearts

only mammals and birds have four-chambered hearts, which are more effective than the two-chambered hearts of fish and the three-chambered hearts of reptiles and amphibians.