Question

The most highly advanced character in crocodile (reptilia) is the presence of
a. Powerful jaws
b. Shelled eggs
c. Thecodont dentition
d. Four chambered heart

Answer 1

Hint: Crocodile belongs to the order Crocodilia of the class Reptilia. It is a semiaquatic and carnivorous reptile that can feed on fishes, amphibians, birds, mammals, and even cannibalize smaller crocodiles. It is a highly advanced reptile that shows various characteristics that are analogous to mammals.

Complete answer:
> Option (A) is incorrect. Powerful jaws are present in crocodiles as their feeding habit is of carnivorous type but this character is not an advanced character that makes crocodiles different from other reptiles.

> Option (B) is incorrect. Crocodiles lay eggs and their eggs are hard-shelled, but translucent at the time of egg-laying. Other reptiles also lay eggs and hence, they are oviparous. Thus, the presence of shelled eggs is not an advanced character in crocodiles that make them different from reptiles.

> Option (C) is incorrect. Thecodont dentition is the rarest dentition found in reptiles and it is present in the members of order Crocodilia. But the presence of this type of dentition does not make them advanced from other reptiles.

> Option (D) is correct. The presence of a four-chambered heart in crocodiles is the highly advanced character in crocodiles that makes them different from other reptiles. The four-chambered heart is the characteristic feature of class Mammalia. Thus, the presence of this type of heart makes crocodiles analogous to mammals.

Hence, the correct answer is option (D).

Note: Crocodiles have a long snout and their unique body structure allows their eyes, ears, and nostrils to remain above the water. They are the most advanced reptiles because of the presence of a four-chambered heart, cerebral cortex, and a functional equivalent of the diaphragm by incorporating the muscles used for aquatic locomotion into respiration.