Biology · Animal Kingdom · NEET
Three. Amphibians have a 3-chambered heart: two auricles (atria) and one ventricle. Because the single ventricle mixes some oxygenated and deoxygenated blood, this is less efficient than the 4-chambered heart of birds and mammals. NEET tip: Fishes = 2, Amphibia and most Reptilia = 3, Crocodile + Birds + Mammals = 4.
No. The amphibian skin is moist and WITHOUT scales. This is a very common NEET trap. Scales belong to Reptilia (dry, keratinised scales), Osteichthyes and Chondrichthyes. The moist scaleless skin of amphibians helps them breathe through the skin, which is why they must stay in damp places.
An amphibian can respire in three ways: by gills, by lungs, and through its moist skin (cutaneous respiration). Tadpoles in water mainly use gills. Adult frogs on land use lungs and their moist skin. This 'triple breathing' is why the moist, scaleless skin matters so much.
Yes. Amphibians are cold-blooded (poikilotherms). Their body temperature changes with the surrounding environment; it is not constant. In extreme summer they do aestivation (summer sleep) and in extreme winter they do hibernation (winter sleep) inside burrows to survive.
The cloaca is a single common chamber where the alimentary canal (digestive tract), the urinary tract, and the reproductive tract all open. From the cloaca, waste and gametes leave the body through one common opening. This shared opening is a standard NEET one-liner for amphibians.
External. Amphibians are oviparous (they lay eggs) and fertilisation is external, meaning the sperm meets the egg outside the body, usually in water. Development is indirect (egg to tadpole larva to adult, with metamorphosis). Reptiles differ: they have internal fertilisation.
Amphibia: moist scaleless skin, 3-chambered heart, external fertilisation, indirect development, breathe by gills/lungs/skin. Reptilia: dry skin with scales, mostly 3-chambered heart (crocodile is 4), internal fertilisation, direct development, breathe by lungs only. The skin and fertilisation type are the fastest ways to tell them apart.
Identify the vertebrate group of animals characterized by crop and gizzard in its digestive system.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It comes from Greek: amphi = double/dual and bios = life. So amphibians can live a dual life, in water and on land.
Bufo (toad), Rana (frog), Hyla (tree frog), Salamandra (salamander), and Ichthyophis (a limbless amphibian). Rana tigrina is the common Indian frog.
Yes. Their eyes have eyelids, and a tympanum (ear drum) represents the ear. The body is divided into head and trunk, and a tail may be present in some.
Yes, sexes are separate (they are not hermaphrodites). Fertilisation is external and they are oviparous with indirect development.
The moist, scaleless skin allows cutaneous respiration (breathing through the skin). It must stay moist, which is why amphibians live in damp habitats and near water.
