Q.Which of the following pairs of animals has non glandular skin
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🔒 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 (B) Chameleon and Turtle.
- Both chameleon and turtle are reptiles, and reptilian skin is dry and cornified, bearing epidermal scales or scutes rather than glands — non-glandular skin.
- A frog's moist skin (option A, C) works as a respiratory surface and is not the dry, non-glandular type reptiles have.
- A pigeon (option C) is a bird; bird skin is dry and largely without glands, but pairing it with frog breaks the "both non-glandular" requirement. …
Reptiles have dry, cornified, non-glandular skin covered with scales or scutes, so a pair drawn from within the reptile class — chameleon and turtle — best fits "non-glandular skin."
The question asks which pair of animals shares non-glandular skin. Skin type differs sharply across vertebrate classes.
- Reptiles (chameleon, turtle, crocodile) have skin described as dry and cornified, bearing epidermal scales or scutes — a covering built to resist water loss on land, with no mention of skin glands.
- Amphibians such as frogs have moist skin that functions as an extra respiratory surface; this moistness depends on secretions, so amphibian skin is not the dry, non-glandular type.
- Birds such as pigeons have dry skin with essentially no glands apart from a single oil gland at the base of the tail — largely non-glandular, but not the same category as reptiles, and pairing a bird with a frog (option C) breaks the shared-condition requirement since the frog's skin is moist. …
Method: Pair-testing against a skin-type checklist
Rather than recalling the answer outright, build a short skin-type checklist (dry/cornified vs moist/glandular) and test each PAIR of animals against it, requiring BOTH members of a pair to pass for the pair to count.
Checklist: Reptile skin = dry, cornified, scaled, non-glandular. Amphibian skin = moist, used for respiration, effectively glandular/wet. Bird skin = dry, largely non-glandular except one tail-base oil gland. Mammal skin = hair-bearing, glandular (sweat/sebaceous glands common).
Testing each option, requiring both members to pass:
- (a) Snake and Frog: snake (reptile) passes the non-glandular test; frog (amphibian) FAILS, since its moist skin functions as a respiratory surface. Pair fails.
- (c) Frog and Pigeon: frog FAILS again for the same reason, even though pigeon (bird) would pass. Pair fails.
- (d) Crocodile and Tiger: crocodile (reptile) passes; tiger (mammal) FAILS, since mammalian skin is well known for varied glands. Pair fails. …
Showing the 12 most recent of 36 on this concept.
- AP EAPCET 2026Set ap-2026-05-19-FN1 markMCQQ.Ammocoete is the larva of (A) Petromyzon (B) Myxine (C) Scoliodon (D) Hippocampus
›Reveal solutionSolution
The ammocoete larva is diagnostic of lampreys (Petromyzon), a jawless cyclostome fish, distinguishing it from the other listed jawed fishes and the hagfish.
Concept and Intuition
Petromyzon (lamprey) has an indirect life cycle: it hatches into a blind, filter-feeding larva called the ammocoete, which burrows in mud and filter-feeds for several years before metamorphosing into the eel-like, jawless, sucker-mouthed adult lamprey. This larval stage is a distinguishing developmental feature of lampreys among vertebrates.
Step-by-Step Solution
- Recall which vertebrate has a distinctly named "ammocoete" larval stage: Petromyzon (lamprey). …
- AP EAPCET 2026Set ap-2026-05-19-FN1 markMCQQ.Match the following: Generic name - Common name: A. Psittacula, B. Aptenodytes, C. Neophron, D. Coracious; I. Penguin, II. Parrot, III. Pigeon, IV. Vulture, V. Blue jay (A) A-II, B-III, C-IV, D-V (B) A-V, B-IV, C-I, D-II (C) A-II, B-I, C-IV, D-V (D) A-III, B-I, C-IV, D-V
›Reveal solutionSolution
This is a straightforward recall match of scientific genus names to their everyday common names: Psittacula–parrot, Aptenodytes–penguin, Neophron–vulture, Coracias–blue jay.
Concept and Intuition
Binomial nomenclature assigns Latinised scientific names to organisms that already have familiar common names; a taxonomy question of this type simply checks whether the student can connect the genus to the animal it names. Psittacula is the genus containing many parakeet/parrot species (e.g., the common rose-ringed parakeet, Psittacula krameri). Aptenodytes is the genus of the largest penguins (king and emperor penguin). Neophron percnopterus is the scientific name of the Egyptian vulture. Coracias (the roller family) — particularly the Indian roller — is popularly called the "blue jay" in India because of its brilliant blue wing flash in flight (not to be confused with the unrelated true blue jay of North America).
Step-by-Step Solution …
- AP EAPCET 2026Set ap-2026-05-19-AN1 markMCQQ.Match the following Generic name | Example A. Ornithorhyncus | I. Flying fox B. Macropus | II. Blue whale C. Pteropus | III. Monkey D. Balaenoptera | IV. Duck billed platypus | V. Kangaroo (A) A-IV, B-I, C-V, D-II (B) A-IV, B-III, C-II, D-I (C) A-II, B-I, C-V, D-IV (D) A-IV, B-V, C-I, D-II
›Reveal solutionSolution
Ornithorhynchus = duck-billed platypus, Macropus = kangaroo, Pteropus = flying fox, Balaenoptera = blue whale. Answer: (D) A-IV, B-V, C-I, D-II.
Concept and Intuition
This is a straightforward genus-to-common-name recall question covering iconic mammals from very different mammalian subgroups: Ornithorhynchus anatinus is the duck-billed platypus, a monotreme (egg-laying mammal); Macropus is the kangaroo genus (Diprotodontia, marsupials); Pteropus is the "flying fox," a large fruit-eating megabat; and Balaenoptera is the rorqual whale genus that includes Balaenoptera musculus, the blue whale, the largest animal known.
Step-by-Step Solution
- A. Ornithorhynchus → Duck-billed platypus ⇒ IV.
- B. Macropus → Kangaroo ⇒ V.
- C. Pteropus → Flying fox ⇒ I. …
- AP EAPCET 2026Set ap-2026-05-20-FN1 markMCQQ.Match the following: Character | Class A. Jacobson's organ | I. Aves B. Pneumatic bones | II. Amphibia C. Vocal sacs | III. Mammalia D. Corpora quadrigemina | IV. Reptelia Correct match is (A) A-IV, B-I, C-II, D-III (B) A-II, B-IV, C-I, D-III (C) A-IV, B-II, C-III, D-I (D) A-I, B-III, C-II, D-IV
›Reveal solutionSolution
Each structure listed is a class-specific anatomical hallmark: Jacobson's organ → Reptilia, pneumatic bones → Aves, vocal sacs → Amphibia, corpora quadrigemina → Mammalia. That gives A-IV, B-I, C-II, D-III, option (A).
Concept and Intuition
Comparative vertebrate anatomy questions test recognition of "signature" structures per class. Building the mental list of one hallmark per class (flight adaptation for birds, brain-roof structure for mammals, chemoreception organ for reptiles, sound-amplifying sacs for frogs) makes such matches fast and reliable.
Step-by-Step Solution
- Jacobson's (vomeronasal) organ — an accessory olfactory structure in the roof of the mouth used to "taste-smell" chemical cues; best developed in snakes and lizards, i.e. Reptilia (IV).
- Pneumatic bones — bones with air cavities connected to the respiratory system, reducing body weight for flight; a bird-specific (Aves, I) adaptation.
- Vocal sacs — membranous pouches near a frog's throat that resonate and amplify mating calls; found in male frogs, i.e. Amphibia (II). …
- AP EAPCET 2026Set ap-2026-05-20-AN1 markMCQQ.Match the following: Characters | Scientific name A. Operculum | I. Scoliodon B. Placoid scales | II. Columba C. Synsacrum | III. Labeo D. Diaphragm | IV. Oryctolagus (A) A-I, B-III, C-IV, D-II (B) A-III, B-I, C-II, D-IV (C) A-III, B-II, C-I, D-IV (D) A-II, B-I, C-IV, D-III
›Reveal solutionSolution
This tests matching diagnostic anatomical structures to representative
vertebrate genera: operculum→Labeo, placoid scales→Scoliodon,
synsacrum→Columba, diaphragm→Oryctolagus.
Concept and Intuition
Each listed structure is a diagnostic feature of a particular vertebrate class:
- Operculum — the bony gill cover found in bony fishes (Osteichthyes), such as Labeo (an Indian carp).
- Placoid scales — small, tooth-like dermal scales unique to cartilaginous fishes (Chondrichthyes), such as Scoliodon (a shark).
- Synsacrum — a rigid structure formed by fusion of the posterior thoracic, lumbar, sacral, and some caudal vertebrae, characteristic of birds, such as Columba (pigeon), providing a stable frame for flight and walking.
- Diaphragm — the dome-shaped muscular sheet separating thoracic and abdominal cavities, found only in mammals, such as Oryctolagus (rabbit).
Step-by-Step Solution
- A. Operculum → bony fish gill cover → Labeo → III.
- B. Placoid scales → cartilaginous fish skin → Scoliodon → I. …
- AP EAPCET 2025Set ap-2025-05-19-AN1 markMCQQ.The type of dentition found in vertebrates that lack a renal portal system (A) Thecodont, homodont, polyphyodont (B) Acrodnot, homodont, diphyodont (C) Thecodont, heterodont, diphyodont (D) Pleurodont, heterodont, polyphyodont
›Reveal solutionSolution
Vertebrates that lack a renal portal system are mammals, and mammals characteristically show thecodont, heterodont, diphyodont dentition.
Concept and Intuition
The renal portal system (venous blood from the tail/hind limbs draining through the kidney before reaching the general circulation) is present in fishes, amphibians, reptiles and birds, but is absent in mammals. Mammalian teeth are set in sockets (thecodont), are of different types — incisors, canines, premolars, molars (heterodont) — and are replaced only once in a lifetime (diphyodont: milk + permanent sets).
Step-by-Step Solution
- Identify the vertebrate group lacking a renal portal system → Mammalia.
- Recall mammalian tooth implantation: thecodont (rooted in sockets).
- Recall mammalian tooth types: heterodont (differentiated into incisors/canines/premolars/molars). …
- AP EAPCET 2025Set ap-2025-05-19-FN1 markMCQQ.Study the following and pick up the correct combinations.
Sl.No. Classes Features Examples I. Osteichthys Filamentous gills Scoliodon II. Amphibia Sternum appeared first time Ichthyophis III. Reptiles Temporal fossae Bungarus IV. Aves Corpus callosum in brain Corvus (A) I, II (B) II, III (C) III, IV (D) I, IV ›Reveal solutionSolution
This tests class-defining features matched with correct examples; combinations I and IV contain factual errors, leaving II and III as the valid pairs.
Concept and Intuition
Each row claims a class, a defining feature, and an example animal. To judge each row we must check (a) whether the feature genuinely defines that class, and (b) whether the example animal is correctly classified.
Step-by-Step Solution
- I. Osteichthyes — Filamentous gills — Scoliodon: Filamentous, operculum-less gills are characteristic of Chondrichthyes (cartilaginous fishes), which lack an operculum — Osteichthyes (bony fishes) have gills covered by an operculum. Also, Scoliodon (a dogfish shark) itself belongs to Chondrichthyes, not Osteichthyes. Row I is wrong on both counts.
- II. Amphibia — Sternum appeared first time — Ichthyophis: Amphibia is the first vertebrate class in which a sternum develops (to anchor pectoral muscles related to terrestrial life), and Ichthyophis is a genuine amphibian (order Gymnophiona/Apoda). This combination is valid.
- III. Reptilia — Temporal fossae — Bungarus: The number and position of temporal fossae (vacuities in the skull for jaw muscle attachment) is the classic feature used to classify amniotes as anapsid/synapsid/diapsid, and is a defining reptilian skull feature; Bungarus (krait) is a genuine reptile. This combination is valid. …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.Ammocoete larva is formed during the embryonic development of (A) Petromyzon (B) Myxine (C) Amphioxus (D) Pyrosoma
›Reveal solutionSolution
Ammocoete is the well-known larval stage of the lamprey, Petromyzon.
Concept and Intuition
Petromyzon (lamprey), a cyclostome, undergoes indirect development through a distinctive filter-feeding larval stage called the ammocoete larva, which lives buried in stream-bed mud before metamorphosing into the adult form.
Step-by-Step Solution
- Ammocoete larva is specifically associated with lampreys (Petromyzon).
- Myxine (hagfish) develops directly, without an ammocoete stage.
- Amphioxus and Pyrosoma are not cyclostomes and do not have this larval form.
- Answer: (A) Petromyzon. …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.Study the following and pick up the correct combinations: S.No./Group/Salient feature/Example - I) Aves / Pneumatic bones / Columba; II) Mammalia / Corpus callosum / Macaca; III) Reptilia / Epidermal scales / Calotes; IV) Chondrichthys / Cartilagenous skeleton / Scoliodon (A) I only (B) I and II only (C) I, II and III only (D) I, II, III and IV
›Reveal solutionSolution
All four Group/Feature/Example combinations are textbook-correct.
Concept and Intuition
Aves have pneumatic (air-filled) bones, exemplified by Columba (pigeon). Mammalia possess a corpus callosum connecting the two cerebral hemispheres, exemplified by Macaca (monkey). Reptilia have epidermal scales, exemplified by Calotes (garden lizard). Chondrichthyes have a cartilaginous endoskeleton, exemplified by Scoliodon (dogfish).
Step-by-Step Solution
- I: Aves — pneumatic bones — Columba: correct.
- II: Mammalia — corpus callosum — Macaca: correct.
- III: Reptilia — epidermal scales — Calotes: correct.
- IV: Chondrichthyes — cartilaginous skeleton — Scoliodon: correct. …
- AP EAPCET 2025Set ap-2025-05-20-FN1 markMCQQ.Anamniotic tetrapod is (A) Pristis (B) Hyla (C) Sphenodon (D) Psittacula
›Reveal solutionSolution
An anamniotic tetrapod is a four-limbed vertebrate that lacks an amnion — this describes Amphibia, so Hyla (a tree frog) is the answer.
Concept and Intuition
Vertebrate classification uses two overlapping criteria here:
- Tetrapod: possessing four limbs (or limb-derived structures) — includes Amphibia, Reptilia, Aves, Mammalia (fish are not tetrapods).
- Amniote vs Anamniote: amniotes (Reptilia, Aves, Mammalia) develop extraembryonic membranes (amnion, chorion, allantois) allowing development away from water; anamniotes (fish and Amphibia) lack these membranes and are tied to water/moist environments for reproduction.
The intersection of "tetrapod" AND "anamniote" is uniquely Amphibia.
Step-by-Step Solution
- Pristis — a sawfish, belonging to Chondrichthyes (cartilaginous fish). It is anamniotic, but NOT a tetrapod (it has fins, not limbs). Excluded.
- Hyla — a genus of tree frogs, Class Amphibia. Amphibians are tetrapods (four limbs) and anamniotes (no amnion; eggs laid in water without a shelled/amniotic egg). This fits both criteria. Correct. …
- AP EAPCET 2025Set ap-2025-05-20-FN1 markMCQQ.Study the following and identify the correct combinations :
Sl.No Class Character Example I. Chodrichthyes Claspers Scoliodon II. Amphibia Three chambered heart Draco III. Reptilia Cleidoic egg Chelone IV. Aves Renal portal system is absent Corvus (A) I and III (B) II and IV (C) III and IV (D) I, II and III ›Reveal solutionSolution
Only the Chondrichthyes–Claspers–Scoliodon and Reptilia–Cleidoic egg–Chelone rows hold up; Draco is wrongly placed under Amphibia, and "absent" overstates what happens to the renal portal system in birds (reduced/bypassed, not absent).
Concept and Intuition
This question tests both taxonomic placement of the named example and the accuracy of the character stated for that class:
- Claspers are copulatory structures in male cartilaginous fish (Chondrichthyes), classically illustrated using the dogfish Scoliodon.
- Cleidoic (self-contained, shelled) eggs are the hallmark reproductive adaptation of Reptilia (and Aves), letting embryos develop away from water; Chelone (a marine turtle) is Reptilia.
- Draco (the flying/gliding lizard) is unambiguously a Reptile, not an Amphibian — so pairing it with "Amphibia" is a straightforward class error regardless of whether "three-chambered heart" is otherwise a true amphibian trait.
- The renal portal system carries venous blood from the hind limbs/tail through the kidneys before the systemic circulation. In fishes, amphibians, and reptiles it functions normally; in birds a valve diverts most blood away from the kidney making the system functionally insignificant, but it is not anatomically absent the way it truly is in mammals — so calling it flatly "absent" in Aves overstates the case compared to describing it as "reduced/non-functional."
Step-by-Step Solution
- Row I: Class Chondrichthyes, Character claspers, Example Scoliodon — all three align correctly. Correct.
- Row II: Draco is Reptilia, not Amphibia — the example doesn't belong to the stated class. Incorrect. …
- AP EAPCET 2024Set ap-2024-05-16-AN1 markMCQQ.Skull is monocondylic in (A) Pisces, amphibians and reptiles (B) Reptiles, birds and mammals (C) Pisces, reptiles and birds (D) Amphibians, reptiles and birds
›Reveal solutionSolution
Monocondylic (single occipital-condyle) skulls occur in Pisces, Reptilia and Aves; Amphibia and Mammalia are dicondylic (two condyles) — so the answer is (C).
Concept and Intuition
The skull articulates with the first vertebra via occipital condyle(s) at the back of the cranium. Comparative vertebrate anatomy classifies this articulation as monocondylic (a single median condyle) versus dicondylic (paired condyles, one on each side of the foramen magnum). Amphibians and mammals independently evolved the paired (dicondylic) condition, giving more stable head movement, while fish, reptiles and birds retain (or converge on) the single-condyle plan.
Step-by-Step Solution
- Recall the two possible conditions: monocondylic (one condyle) vs dicondylic (two condyles).
- Mammals are a textbook dicondylic group — this immediately eliminates option (B), which lists mammals as monocondylic.
- Amphibians are also dicondylic — this eliminates options (A) and (D), both of which list amphibians as monocondylic. …
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