On what bases are vertebrates further classifed
Answers
Answer:
Explanation:Vertebrates are further classified according to several criteria like exoskeleton, respiratory organs, method of giving birth, number of chambers in heart, mode of living etc. They are further classified into classes Pisces, Amphibia, Reptilia, Aves and Mammals.
Pisces include the fishes. They are aquatic, cold-blooded animals having 2 chambers of heart. Their skin is covered with scales/plates. They lay eggs and respire through gills. They excrete urea. Endoskeleton may be bony or cartilagenous.
Amphibians on the other hand live partly in water and partly on land. Their skin is smooth without scales. Respiration is through gills, lungs, skin or buccal lining. They possess 3 chambered heart and are oviparous. They are cold-blooded.
Reptiles are the creeping vertebrates possessing dry scaly exoskeleton. They are cold-blooded, breathe through lungs and possess 3 chambered heart. They are oviparous and excrete uric acid.
Aves include the birds. They are warm-blooded, oviparous vertebrates with a covering of feathers. Their fore-limbs are modified into wings for flight. Respiration is through lungs and 4 chambered heart is present.
Mammals possess mammary glands for feeding the young. They are warm-blooded with 4 chambered heart. They are viviparous. They possess external pinna and hair on skin. Parental care is highly developed. They excrete urea.
Answer:
Vertebrates include amphibians, reptiles, mammals, and birds, as well as the jawless fishes, bony fishes, sharks, and rays. More than 64,000 species of vertebrates have been described, but the extant vertebrate species represent only a small portion of all the vertebrates that have existed.