Aves are a class of endothermic vertebrates, commonly known as birds. These animals fall under the phylum Chordata carrying specific features such as toothless jaws with beak, lying of eggs with a hard shell, etc.
Estimated 9000 species of Aves are present in the terrestrial animal kingdom. The capability of flying is the most dominant feature of this species. Their lightweight skeleton structure with strong but hollow bones helps them to fly.
Along with these salient features of Aves, the most visually attractive and remarkable characteristic is their colourful feather. A wide range of feather with its unique pattern can be seen in the class of animals.
Aves are also called social animals as they can build nests, show territorial behaviour, and engage in courtship.
Some of the Aves examples are Pigeon, Parrot, Sparrow, Owls, Penguins, Hummingbird, Crow, etc.
Some general characteristics of Aves are the following-
One of the most visible class Aves characteristics is they are bipedal feathered animals. The fore-limbs of birds have developed into wings that help them to fly.
Their back-limbs have become legs that help them for swimming, walking, etc. Mostly, birds have four toes on their leg. However, two or three toes are also rarely visible.
Aves are homoiothermic or warm-blooded creatures. Because of this, birds can keep a stable body temperature even when flying at high altitudes.
Birds don’t have any skin glands other than the uropygium gland or oil gland. This gland is situated near the tail.
Their jaws are transformed into beaks and don’t have any tooth. With the help of beak, birds can feed in different ways like tearing flesh, crushing seeds, sipping nectar, etc.
Additional chambers called gizzard and crop are found in their alimentary canal. The crop chamber helps to soften the stored food, whereas the gizzard crushes the food. Few seed-eating birds like pigeons lack gall bladder in their system.
Lungs act as the primary respiratory organ in birds. Their lungs are inelastic and spongy. Lungs have air sacs to supplement respiration.
In birds, an organ called syrinx helps to produce voice.
Birds have a four-chambered heart and a reduced renal portal system. Also, their cardio-vascular system lacks sinus venosus.
The kidneys in birds are metanephric that help to filter the nitrogenous fluid waste via the ureters, into the cloaca. Their renal system lacks a urinary bladder.
Aves have a more developed brain then reptiles. Their brain consists of the cerebrum, cerebellum, and large optic lobes. Furthermore, 24 cranial nerves are present in their nervous system.
Birds have highly developed sight, but their smelling sense is poor. They have pecten in eyes and visible ear openings. Their ears are divided into three parts – internal, middle, and external.
Their endoskeleton is bony, and the bones are hollow. For this reason, the bones in birds are lighter than most animals. The bones lack bone marrow. The skull consists of a single occipital condyle.
The female birds have one ovary on the left side of the body and one oviduct. However, non-functional right ovary and oviduct can be found in some cases.
Sexual dimorphism can be found in Aves, and they are oviparous. Bird eggs consist of four embryonic membranes – yolk, allantois, amnion, chorion.
Some other class Aves facts – they are spindle-shaped, and their shape helps to reduce the wind resistance while flying. Also, their feather passes the air to minimise air friction.
The fight muscles of Aves are highly developed.
Classification of Aves
Aves can be categorised into two classes. Here is the Aves classification up to order-
This class of Aves is extinct. Their beaked jaw had teeth and tail was long like a lizard.
Example - Archaeopteryx
This class of Aves is both extant and extinct. They have toothless beaked-jaw and a short tail.
Example: Duck, Penguin, etc.
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1. What kingdom does birds belong to?
Birds belong to the phylum Chordata of the kingdom Animalia.
2. What is the class name for birds?
Aves is the class name of birds. It’s clade is Ornithurine.
3. What are some characteristics of Aves?
Some important Aves characteristics are – Aves have a beaked jaw with no tooth, most members of this species can fly, lay eggs, and has colourful feathers.