Q.Which one of the following is a non-poisonous snake?
🔒You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Classes Of Vertebrata
From Fish to Birds to Humans — The Big Picture
Think of vertebrates as animals with a backbone. That's the club you belong to — humans, dogs, frogs, fish, snakes, birds. But inside that club, there's an enormous range of body plans. Some have scales, some have feathers. Some live only in water, some on land. Some lay eggs, some give birth to live young.
The classification of vertebrates is simply a way of grouping them by shared structural features — things you can see and feel, like skin covering, heart chambers, or how they breathe. It's not random. Each group represents a major evolutionary step in how animals solved the problems of living on Earth.
The Seven Classes — What Makes Each One Distinct
1. Cyclostomata — The Jawless Vertebrates
These are the most primitive living vertebrates. They look like eels but have a round, sucker-like mouth with no jaws. Their skeleton is made of cartilage (not bone), and they have no paired fins.
Cyclostomes are parasitic or scavenging. The lamprey attaches to fish with its sucker mouth and rasps a hole to feed on blood.
Examples: Lamprey, Hagfish.
2. Chondrichthyes — The Cartilaginous Fish
Sharks, rays, and skates. Their skeleton is entirely cartilage — the same flexible stuff in your ears and nose. They have jaws and paired fins, and their skin is covered with tiny, tooth-like scales called placoid scales.
Do not confuse Chondrichthyes with bony fish. The key difference: cartilage skeleton vs bony skeleton. Also, most cartilaginous fish have gill slits (no operculum covering the gills).
Examples: Shark, Stingray.
3. Osteichthyes — The Bony Fish
This is the largest group of vertebrates. Their skeleton is made of bone. They have a swim bladder (a gas-filled sac that controls buoyancy) and an operculum (a bony flap covering the gills). Their scales are flat, overlapping plates called cycloid or ctenoid scales.
If you see a fish with a bony skeleton and a flap covering its gills, it's Osteichthyes. If it has a cartilage skeleton and open gill slits, it's Chondrichthyes.
Examples: Rohu, Salmon, Goldfish.
4. Amphibia — The Double-Life Vertebrates
Amphibians live part of their life in water and part on land. Their skin is moist and glandular (no scales). They lay eggs without a shell in water, and the young (tadpoles) breathe through gills. Adults develop lungs and can breathe air.
| Feature | Amphibia |
|---------|----------|
| Skin | Moist, glandular, no scales |
| Eggs | Laid in water, no shell |
| Respiration | Gills (larva), lungs + skin (adult) |
| Heart | 3-chambered |
Examples: Frog, Salamander, Toad.
5. Reptilia — The First True Land Vertebrates
Reptiles were the first vertebrates to fully break free from water. Their skin is dry, thick, and covered with scales (made of keratin). They lay shelled eggs on land — the amniotic egg that protects the embryo from drying out. They breathe only through lungs.
| Feature | Amphibia | Reptilia |
|---------|----------|----------|
| Skin | Moist, no scales | Dry, scales |
| Eggs | No shell, in water | Shelled, on land |
| Heart | 3-chambered | 3-chambered (except crocodiles — 4) |
Examples: Lizard, Snake, Turtle, Crocodile.
6. Aves — The Feathered Vertebrates
Birds are the only animals with feathers. Their forelimbs are modified into wings (even flightless birds like ostriches have wings). They have a beak with no teeth, and their bones are hollow (pneumatic) to reduce weight for flight. They lay hard-shelled eggs and are warm-blooded (endothermic).
Birds have a 4-chambered heart — the same as mammals. This allows complete separation of oxygenated and deoxygenated blood, supporting high metabolic rates needed for flight.
Examples: Pigeon, Eagle, Sparrow.
7. Mammalia — The Milk-Giving Vertebrates
You are here. Mammals have mammary glands that produce milk to feed their young. Their skin has hair (at least at some stage). They are warm-blooded, have a 4-chambered heart, and most give birth to live young (except monotremes like the platypus, which lay eggs).
Key mammalian features: …
The correct option is (C) Python.
- Cobra (Naja), krait (Bangarus) and viper (Vipera) are all explicitly named as poisonous snakes.
- Python is not included among the poisonous snakes and, unlike them, is a constrictor that overpowers prey physically rather than by venom. …
Cobra, viper and krait are all named poisonous snakes, leaving python — a non-venomous constrictor — as the correct non-poisonous choice.
Reptiles include a mix of venomous and non-venomous snake species, and the chapter specifically lists the poisonous ones.
- Naja (cobra), Bangarus (krait) and Vipera (viper) are each explicitly named as poisonous snakes. …
Method: Named-list elimination
Instead of recalling directly which snake is non-venomous, recall the specific SHORT list of snakes explicitly named as poisonous, and treat anything NOT on that list as the answer by elimination.
Step 1 — recall the named poisonous list. The chapter specifically names cobra (Naja), krait (Bangarus) and viper (Vipera) as poisonous snakes. This is a short, specific, memorable trio.
Step 2 — check each option against the list.
- Cobra — appears on the poisonous list. Eliminate as the answer.
- Viper — appears on the poisonous list. Eliminate as the answer.
- Krait — appears on the poisonous list. Eliminate as the answer.
- Python — does NOT appear on the poisonous list at all.
Step 3 — cross-check with independent knowledge of the animal's hunting method. Pythons are constrictors: they kill prey by coiling around it and squeezing, a physical method that has nothing to do with venom. This independently supports python's absence from the poisonous list — it does not need venom because it hunts a completely different way. …
- Council of Higher Secondary Education, Manipur (Higher Secondary 1st Year) 2024Set ANNUAL2 marksQ.Distinguish between lizards and snakes by giving two points.
›Reveal solutionSolution
Lizards differ from snakes mainly in having movable eyelids with visible ear openings and functional limbs, all of which snakes lack.
Both lizards and snakes are reptiles (class Reptilia, order Squamata), but they show clear distinguishing features:
- Eyes and ears: Lizards possess movable eyelids that can blink, and they have a visible external ear opening on each side of the head. Snakes, in contrast, have no movable eyelids — each eye is permanently covered by a fixed, transparent scale (spectacle) — and they lack any external ear opening.
- Limbs: Lizards have two pairs of well-developed limbs used for walking/running. Snakes are completely limbless; their body is elongated and they move by muscular undulation of the trunk. …
- Council of Higher Secondary Education, Manipur (Higher Secondary 1st Year) 2022Set ANNUAL2 marksQ.List two characteristics features of Reptiles.
›Reveal solutionSolution
Reptiles are recognised by their dry, scaly skin and cold-blooded (ectothermic) physiology, among other features.
Reptiles (Class Reptilia) are terrestrial or aquatic vertebrates that share several distinguishing features:
- Dry, cornified skin with epidermal scales: the body is covered by thick, dry skin bearing scales made of keratin, which prevents water loss and provides protection — unlike the moist skin of amphibians.
- Ectothermy (poikilothermy): reptiles cannot internally regulate their body temperature; their body temperature varies with, and depends on, the surrounding environment, which is why they are often seen basking in the sun. …
- Council of Higher Secondary Education, Manipur (Higher Secondary 1st Year) 2021Set ANNUAL2 marksQ."Ornithorhynchus is considered as an exceptional mammal". Justify.
›Reveal solutionSolution
The platypus (Ornithorhynchus) is a mammal, evidenced by its mammary glands and hair, yet it lays eggs and has a cloaca like a reptile — an unusual mix of mammalian and reptilian traits.
Ornithorhynchus anatinus, the duck-billed platypus, belongs to the subclass Prototheria within class Mammalia. It qualifies as a mammal because it possesses the two defining mammalian characteristics: hair/fur covering the body and mammary glands that secrete milk to nourish the young. However, it departs sharply from the typical mammalian reproductive pattern seen in almost all other mammals (viviparity, giving birth to live young): the platypus is oviparous, laying soft-shelled eggs that are incubated outside the body, much like a reptile or bird. After hatching, the young lap up milk that oozes from the mother's mammary gland openings on her skin (Prototherians lack nipples). Additionally, like reptiles, the platypus has a single posterior opening, the cloaca, through which faecal matter, urine, …
- Council of Higher Secondary Education, Manipur (Higher Secondary 1st Year) 2020Set ANNUAL2 marksQ.Enumerate two similarities between Aves and Mammalia.
›Reveal solutionSolution
Aves and Mammalia share two major features: both are warm-blooded (endothermic) and both have a completely divided, four-chambered heart.
-
Warm-bloodedness (endothermy/homeothermy): Both birds and mammals can generate and maintain a constant internal body temperature regardless of the surrounding environmental temperature, using internal metabolic heat production and various insulating/regulating adaptations (feathers in birds, hair/fur in mammals). This is unlike "cold-blooded" (ectothermic) animals such as reptiles and amphibians, whose body temperature varies with the environment.
-
Four-chambered heart: Both groups have a heart divided into two atria and two ventricles, with a complete septum separating the two sides. This keeps oxygenated blood (from the lungs) and deoxygenated blood (from the body) completely separate, allowing efficient, high-pressure circulation that supports their high metabolic rate.
…
-
🎓Unlock everything free for 14 days
- ✓Full step-by-step solutions
- ✓Concept-first explanations
- ✓Methods, shortcuts & mistakes
- ✓PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.