Class-Reptilia Questions in English

(D) Homeotherms (or endotherms) are animals that can maintain a constant body temperature regardless of the environmental temperature. Birds $(Aves)$ and mammals $(Mammalia)$ are homeotherms.
$Psittacula$ (Parrot) is a bird.
$Macropus$ (Kangaroo) is a mammal.
$Camelus$ (Camel) is a mammal.
$Chelone$ (Green sea turtle) belongs to the class $Reptilia$. Reptiles are poikilotherms (ectotherms),meaning they cannot maintain a constant body temperature and their body temperature fluctuates with the environment.
Therefore,$Chelone$ is not a homeotherm.

(D) $Chamaeleon$ is a specialized lizard known for its prehensile tail,which it uses to coil around twigs for stability while climbing trees.
It exhibits protective colouration (camouflage) to blend in with its surroundings,such as leaves and twigs,to avoid predators and hunt prey effectively.

(N/A) $\rightarrow$ The class name refers to their creeping or crawling mode of locomotion (Latin,$repere$ or $reptum$,to creep or crawl).
$\rightarrow$ They are mostly terrestrial animals and their body is covered by dry and cornified skin,epidermal scales or scutes.
$\rightarrow$ They do not have external ear openings. $Tympanum$ represents the ear.
$\rightarrow$ Limbs,when present,are two pairs.
$\rightarrow$ Heart is usually three-chambered,but four-chambered in crocodiles.
$\rightarrow$ Reptiles are poikilotherms (cold-blooded).
$\rightarrow$ Snakes and lizards shed their scales as skin cast.
$\rightarrow$ Sexes are separate (dioecious).
$\rightarrow$ Fertilisation is internal.
$\rightarrow$ They are oviparous and development is direct.
$\rightarrow$ Examples: $Chelone$ (Turtle),$Testudo$ (Tortoise),$Chameleon$ (Tree lizard),$Calotes$ (Garden lizard),$Crocodilus$ (Crocodile),$Alligator$ (Alligator),$Hemidactylus$ (Wall lizard),Poisonous snakes - $Naja$ (Cobra),$Bangarus$ (Krait),$Vipera$ (Viper).

(A) In most reptiles,the heart is three-chambered with an incomplete division of the ventricle.
However,crocodiles are an exception among reptiles as they possess a four-chambered heart with a completely divided ventricle,consisting of two atria and two ventricles.

(A) The eggs of reptiles and birds are covered by a hard,calcareous shell.
This shell is primarily composed of calcium carbonate $(CaCO_3)$.
It provides protection to the developing embryo from environmental stress and prevents desiccation.

(B) The organism 'Kashyapa' refers to a tortoise or turtle.
Tortoises and turtles belong to the class $Reptilia$ in the animal kingdom.
They are cold-blooded,air-breathing vertebrates characterized by a bony or cartilaginous shell developed from their ribs.

(B) The $Tuatara$ ($Sphenodon$ $punctatus$) is a reptile endemic to New Zealand.
It belongs to the order $Rhynchocephalia$ within the class $Reptilia$.
It is often referred to as a 'living fossil' because it is the only surviving member of its order,which flourished during the Mesozoic era.
Therefore,the correct option is $B$.

(D) Snakes belong to the class $Reptilia$.
Due to their elongated body structure and mode of locomotion, they lack limbs, which results in the absence of both pectoral and pelvic girdles.
Additionally, snakes do not possess a urinary bladder, and they lack a sternum (breastbone) because they do not have a rib cage that connects to a central ventral bone.
Therefore, all the mentioned structures are absent in snakes.

(B) The skin of reptiles is dry,cornified,and devoid of glands. They possess epidermal scales or scutes on their body surface,which helps in preventing water loss and provides protection.

(C) The scientific name of the king cobra is $Ophiophagus$ $hannah$.
$Naja$ $naja$ is commonly known as the Indian cobra or Nag.
$Bungarus$ $caeruleus$ is the common krait.
$Daboia$ $russelii$ is the Russell's viper.

(A) The zoological name of the common Indian krait is $Bungarus$ $caeruleus$.
It is a highly venomous snake found in the Indian subcontinent.
$Ophiophagus$ $hannah$ is the King Cobra,$Daboia$ $russelii$ is Russell's viper,and $Naja$ $naja$ is the Indian cobra.

(D) Among the given options,$Cobra$,$Krait$,and $Viper$ are examples of poisonous snakes. $Python$ is a non-poisonous snake that kills its prey by constriction.

(A) $1$. The venom of the cobra (genus $Naja$) is primarily neurotoxic,which affects the nervous system.
$2$. The venom of sea snakes (family $Hydrophiinae$) is also primarily neurotoxic.
$3$. The venom of vipers (family $Viperidae$) is primarily haemotoxic,which affects the blood and circulatory system.
$4$. Since all three statements ($I, II,$ and $III$) are scientifically accurate,the correct option is $A$.

(D) Jacobson's organs (also known as the vomeronasal organs) are auxiliary olfactory sense organs.
They are found in many tetrapods,including mammals and reptiles.
While they are present in rats,snakes,and humans (though often vestigial in humans),they are particularly well-developed in snakes and lizards,where they play a crucial role in detecting chemical cues in the environment.
Therefore,they are present in all the listed organisms.

(D) In the animal kingdom,the structure of erythrocytes varies across classes.
Amphibians,Reptiles,and Birds (Aves) possess erythrocytes that are oval in shape,biconvex,and nucleated.
In contrast,Mammals possess erythrocytes that are circular,biconcave,and denucleated (lacking a nucleus at maturity).

(C) Poison glands in snakes are specialized structures derived from the parotid salivary glands. These glands produce venom,which is injected through specialized teeth known as fangs to immobilize or kill prey.

(C) Reptiles are generally characterized by having a three-chambered heart,consisting of two atria and one partially divided ventricle. However,this is not true for all reptiles,as members of the order Crocodilia (such as crocodiles and alligators) possess a four-chambered heart. Therefore,the statement that all reptiles have a three-chambered heart is incorrect.

(B) Most reptiles,such as $Vipera$ (viper snake),$Testudo$ (tortoise),and $Hemidactylus$ (wall lizard),possess a three-chambered heart consisting of two atria and one partially divided ventricle.
However,$Crocodilus$ (crocodile) is an exception within the class $Reptilia$ as it possesses a completely four-chambered heart,similar to birds and mammals.
Therefore,the correct answer is $Crocodilus$.

(A) Most reptiles,such as $Testudo$ (Tortoise),$Chelone$ (Turtles),and $Bungarus$ (Krait snake),possess a three-chambered heart.
However,the $Alligator$,which belongs to the order $Crocodilia$ of the class $Reptilia$,is an exception because it possesses a four-chambered heart.

(A) The $Crocodile$ is characterized by a moderately long and pointed snout. It is known to be highly aggressive and poses a significant danger to humans. In contrast,$Alligators$ have a broad and rounded snout,$Gavialis$ (Gharial) have a very long and slender snout adapted for eating fish,and $Salamandra$ is an amphibian that does not possess a snout.

(C) $Sphenodon$ belongs to the order $Rhynchocephalia$,class $Reptilia$.
$Sphenodon$ is commonly called $Tuatara$ and possesses a pineal gland or a third eye.
$Sphenodon$ retains ancestral characters of stem reptiles,hence it is referred to as a living fossil.

(D) Lizards exhibit autotomy,which is the voluntary shedding of their tail to distract predators,followed by regeneration of the tail.
Most lizard species are oviparous,meaning they lay eggs protected by a shell.
In venomous snakes,the poison glands are specialized modifications of the superior labial or parotid glands.
Therefore,all the given statements are correct.

(B) Most lizards are oviparous,meaning they lay eggs. However,some species exhibit viviparity,where they give birth to live young. Among the given options,$Chameleon$ is a well-known example of a viviparous lizard. $Uromastix$ is oviparous,and $Hydrophis$ is a sea snake,not a lizard.

(B) Poikilotherms are organisms that change their internal body temperature according to the surroundings.
$1$. Amphibia: These are poikilotherms and are dicondylic (having two occipital condyles).
$2$. Reptilia: These are poikilotherms and are monocondylic (having a single occipital condyle).
$3$. Aves: These are homeotherms (maintain a constant body temperature) and are monocondylic.
$4$. Mammals: These are homeotherms and are dicondylic.
Therefore,poikilothermous animals with a single occipital condyle belong to the class Reptilia.

(C) The lateral line system is a sensory system found in aquatic vertebrates,including fishes and the larval stages of amphibians (like the tadpole larva of a frog),which helps them detect movement,vibration,and pressure gradients in the surrounding water.
$1$. Fishes,including cartilaginous fishes,possess a well-developed lateral line system.
$2$. The tadpole larva of a frog is aquatic and also possesses a lateral line system.
$3$. Reptiles are primarily terrestrial vertebrates and have evolved to live on land; therefore,they lack the lateral line sense organs as they are not required for their survival in a terrestrial environment.

(N/A) $\rightarrow$ Following are the two modifications in reptiles required for terrestrial mode of life:
$(a)$ Dry and cornified skin with epidermal scales,which prevents water loss from the body.
$(b)$ Internal fertilization,which allows reproduction to occur independently of an external water source.

(A) Most reptiles possess a $3$-chambered heart,consisting of two atria and one partially divided ventricle. However,crocodiles are an exception among reptiles as they possess a $4$-chambered heart,similar to birds and mammals,with two atria and two completely separated ventricles. Therefore,the crocodile is the exception.

(D) The class $Reptilia$ is characterized by the presence of dry and cornified skin,epidermal scales,or scutes.
These animals are poikilotherms (cold-blooded).
Garden lizard $(Calotes)$,Crocodile $(Crocodilus)$,and Cobra $(Naja)$ are all members of the class $Reptilia$.
Therefore,all the given options possess dry and cornified skin.

(D) Reptiles evolved from amphibians during the Carboniferous period.
Unlike amphibians,reptiles developed the ability to lay thick-shelled eggs that are resistant to desiccation,allowing them to survive and hatch on land without drying out in the sun.
Modern-day descendants of the ancient reptilian lineage include turtles,tortoises,and crocodiles.
Therefore,all the given statements are correct.

(C) The heart structure varies among vertebrates:
$1$. $Scoliodon$ (Dogfish) is a cartilaginous fish,which has a two-chambered heart (one atrium and one ventricle).
$2$. $Hippocampus$ (Seahorse) is a bony fish,which also has a two-chambered heart.
$3$. $Chelone$ (Green sea turtle) is a reptile. Most reptiles,including turtles,possess a three-chambered heart consisting of two atria and one partially divided ventricle.
$4$. $Pteropus$ (Flying fox/Bat) is a mammal,which has a four-chambered heart.
Therefore,the correct answer is $Chelone$.

(D) $Vipera$ (Viper),$Naja$ (Cobra),and $Bungarus$ (Krait) are all examples of highly poisonous snakes. $Azgar$ (Python) is a non-poisonous snake that kills its prey by constriction.

(D) An oviparous animal is one that lays eggs,which then hatch outside the mother's body.
$A$. $Scoliodon$ (Dogfish) is a viviparous shark,meaning it gives birth to live young.
$B$. $Viper$ is an ovoviviparous snake,where eggs hatch inside the mother's body.
$C$. $Scorpion$ is generally ovoviviparous or viviparous.
$D$. $Cobra$ is an oviparous animal,as it lays eggs that develop and hatch externally.

(D) Both snakes and lizards belong to the class $Reptilia$.
These animals possess an exoskeleton of keratinized scales or scutes.
As they grow,they periodically shed their outer layer of skin,a process known as ecdysis or molting,which is often observed as a 'skin cast'.

(D) Reptiles belong to the class $Reptilia$. They are mostly terrestrial animals and their body is covered by dry and cornified skin,epidermal scales,or scutes. They do not have slimy skin; instead,their skin is dry. They are mostly oviparous and exhibit direct development. Therefore,both statements $(1)$ and $(2)$ are correct.

(C) The cloaca in certain aquatic animals,such as the $Turtle$ (specifically species like the $Fitzroy$ River turtle),acts as an accessory respiratory organ.
These animals possess specialized bursae (cloacal bursae) that are highly vascularized.
By pumping water in and out of the cloaca,the animal can extract dissolved oxygen from the water,allowing it to remain submerged for extended periods without surfacing to breathe.

(D) tortoise.
$Tortoises$ possess an exoskeletal shell made of bony plates covered by keratin and an endoskeleton comprising a backbone and internal bones.
This dual skeletal system provides protection and structural support.
This distinguishes $tortoises$ from $frogs$ (which have an endoskeleton only),$jellyfish$ (which lack both a true exoskeleton and endoskeleton),and $freshwater$ $mussels$ (which have an exoskeleton only).