Reptile Characteristics & Poikilothermy — NEET Biology
✅ Asked in NEET 2018Which one of these animals is not a homeotherm? NEET Year: NEET 2018
Which one of these animals is not a homeotherm? NEET Year: NEET 2018
Answer & NCERT explanation
Correct answer: B — Chelone
Chelone (turtle) is a reptile and therefore cold-blooded (poikilothermic), not a homeotherm. Homeotherms maintain constant body temperature internally. Macropus (kangaroo), Camelus (camel), and Psittacula (parrot) are all warm-blooded animals that regulate their body temperature, making them homeotherms.
Read more NCERT concept on the PYQ
The class name refers to their creeping or crawling mode of locomotion (Latin, repere or reptum, to creep or crawl). They are mostly terrestrial animals and their body is covered by dry and cornified skin, epidermal scales or scutes. They do not have external ear openings. Tympanum represents ear. Limbs, when present, are two pairs. Heart is usually three-chambered, but four-chambered in crocodiles. Reptiles are poikilotherms. Snakes and lizards shed their scales as skin cast. Sexes are separate. Fertilisation is internal. They are oviparous and development is direct.
NTA focuses on identifying reptile features, especially that reptiles are poikilotherms (cold-blooded animals with variable body temperature). Students often confuse poikilotherms with homeotherms or ectotherms/endotherms terminology. Remember: reptiles are ectothermic poikilotherms—they regulate body temperature through environmental means, not internal metabolic control. Key NEET trap: questions may ask whether reptiles maintain constant body temperature (they don't) or show external ear openings (they lack external openings; only tympanum). Quick recall: three-chambered heart in most reptiles but four in crocodiles, dry cornified skin with scales, internal fertilization, and direct development distinguish the entire class.
What does NCERT say about class name refers to?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.