Biology · Structural Organisation in Animals · NEET
A frog is cold-blooded. It does not keep a constant body temperature. Its body temperature changes with the temperature of the environment. Animals like this are called poikilotherms or cold-blooded animals. NEET often gives 'poikilotherm' as one option, so remember the word.
The most common species of frog found in India is Rana tigrina (the Indian bullfrog). It belongs to class Amphibia of phylum Chordata. NCERT names this exact species, so it is safe to quote in NEET.
'Poikilo' means variable and 'therm' means heat. Because the frog's body temperature varies with the outside temperature instead of staying fixed, it is called a poikilotherm. This is the same as saying cold-blooded.
No. NCERT clearly states the frog never drinks water. It absorbs water through its skin. The skin stays moist and slippery because of mucus, which also helps in skin respiration (cutaneous respiration).
No. A frog can live both on land and in freshwater. That is why it belongs to class Amphibia ('amphi' means both). This double habitat is a key general feature tested in NEET.
Frog's heart when taken out of the body continues to beat for some time. Select the best option from the following statements: (a) Frog is a poikilotherm (b) Frog does not have any coronary circulation (c) Heart is 'myogenic' in nature (d) Heart is autoexcitable
Try the real previous-year questions from this chapter — each with the answer and a full solution.
The frog belongs to phylum Chordata and class Amphibia. Amphibians can live both on land and in freshwater.
A frog can change its body colour to hide from enemies while sitting on grass or dry land. This protective colouration (camouflage) is called mimicry in NCERT.
The dorsal (upper) side is generally olive green with dark irregular spots, and the ventral (lower) side is uniformly pale yellow. Bulging eyes and this spotted skin are common to both males and females.
During peak summer and winter the frog hides in deep burrows. Summer sleep is called aestivation and winter sleep is called hibernation. This is covered in detail in the next concept.
The skin has mucous glands that keep it moist and slippery. Moist, highly vascular skin lets the frog absorb water and exchange gases (skin respiration) both in water and on land.
