Characteristics of Class Aves are given below:
1) The members of class aves are commonly known as birds.
2) They are worm-blooded with an exoskeleton of feathers.
3) Body usually spindle shaped, with four divisions: head, neck, trunk, and tail; neck disproportionately long for balancing and food gathering.
4) Limbs paired; forelimbs usually modified for flying; posterior pair variously adapted for perching, walking, and swimming; foot with four toes.
5) Epidermal covering of feathers and leg scales.
6) Thin integument of epidermis and dermis.
7) No sweat glands.
8) Oil or preen gland at base of tail.
9) Pinna of ear rudimentary.
10) Fully ossified skeleton with air cavities.
11) Skull bones fused with one occipital condyle.
12) Each jaw covered with a keratinized sheath, forming a beak.
13) No teeth; ribs with strengthening, uncinate processes.
14) Posterior caudal vertebrae reduced and fused as the pygostyle.
15) Pelvic girdle a synsacrum.
16) Aerythrocytes sternum usually well developed with keel.
17) Single bone in middle ear.
18) Fused bones in pelvis, feet, hands, and head
19) Lightweight bones (bones that are either hollow or spongy/strutted)
21) Possess a four-chambered heart and in general exhibit high metabolic rates
22) Adept navigational abilities in many species
23) Extraordinary communication and song production
24) Nervous system well developed, with 12 pairs of cranial nerves and brain with large cerebellum and optic lobes. Circulatory system consists of four-chambered heart with two atria and two ventricles.
25) Sexes separate; testes paired, with the vas deferens opening into the cloaca.
26) Females have left ovary and oviduct only.
27) Prental care is well developed.
1. Corvous splenders
2. Passer domestics
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