Question

Given below are two statements :
Statement I : The class name Reptilia refers to creeping or crawling mode of locomotion.
Statement II : All organisms belonging to Reptilia have three chambered heart.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Statement I is incorrect but Statement II is correct
• B. Both Statement I and Statement II are correct
• C. Both Statement I and Statement II are incorrect
• D. Statement I is correct but Statement II is incorrect

Hint:

Whenever a biology question contains absolute terms like "All", "Always", or "Never", look closely for evolutionary exceptions. For Class Reptilia, the classic exception to remember is: \[ \text{Reptiles} \rightarrow \text{3-chambered heart} \quad \textbf{EXCEPT} \quad \text{Crocodiles} \rightarrow \text{4-chambered heart} \]

Answer 1

The Correct Option is D

Concept: The classification of animals in the animal kingdom is based on distinctive morphological, anatomical, and evolutionary characteristics. Class Reptilia forms a major group under the subphylum Vertebrata. Understanding the diagnostic traits of this class—such as its etymology, locomotor adaptations, and the comparative anatomy of its circulatory system—helps identify the general characteristics alongside key evolutionary exceptions.

Step 1: Evaluation of Statement I
Let us analyze the origin and meaning of the class name

Reptilia. The term 'Reptilia' is derived directly from the Latin words repre or reptum, which mean "to creep" or "to crawl". Therefore, the name of the class directly highlights their characteristic creeping or crawling mode of locomotion. Most reptiles move with their bellies close to or touching the ground due to the lateral placement of their limbs. Hence,

Statement I is completely correct.

Step 2: Evaluation of Statement II
Let us analyze the circulatory anatomy of organisms belonging to Class Reptilia. The standard structural configuration of a reptile's heart features a

three-chambered structure, consisting of:

• Two distinct atria (Left atrium and Right atrium)

• One incomplete or partially divided ventricle
However, biological groups often exhibit evolutionary modifications. Within Class Reptilia, order

Crocodilia (which includes crocodiles, alligators, caimans, and gharials) represents a major evolutionary exception. Crocodiles possess a highly evolved, completely separated interventricular septum, resulting in a true

four-chambered heart (two atria and two ventricles), much like birds and mammals. Because crocodiles belong to Reptilia but do not have a three-chambered heart, the generalized statement stating "All organisms belonging to Reptilia have three chambered heart" becomes factually invalid. Hence,

Statement II is incorrect.

Conclusion:
Since Statement I is correct and Statement II is incorrect, the most appropriate choice is option (4).