Zoology Question 49 – AP-EAMCET 2025
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Osteichthys (bony fishes) typically possess filamentous gills. However, the example provided, Scoliodon (dogfish), is a cartilaginous fish (Chondrichthyes), not a bony fish. Therefore, combination I is incorrect.
Remember that Scoliodon is a shark, which belongs to the class Chondrichthyes (cartilaginous fishes), not Osteichthyes (bony fishes).
Amphibians were the first vertebrates to evolve a sternum, which provides an attachment point for pectoral muscles and supports the forelimbs for terrestrial locomotion. Ichthyophis (caecilian) is indeed an amphibian. Therefore, combination II is correct.
The appearance of the sternum in amphibians was a crucial adaptation for supporting the body against gravity in a terrestrial environment.
Reptiles are characterized by the presence or absence of temporal fossae (openings in the temporal region of the skull), which are important for jaw muscle attachment. Bungarus (krait) is a type of venomous snake, which belongs to the class Reptilia. Therefore, combination III is correct.
Temporal fossae are key features used in classifying reptiles into anapsids, synapsids, and diapsids based on their skull structure.
Aves (birds) do not possess a corpus callosum. The corpus callosum is a large nerve fiber tract that connects the two cerebral hemispheres, and it is a characteristic feature primarily found in placental mammals. Corvus (crow) is a bird, but the feature is incorrect. Therefore, combination IV is incorrect.
The corpus callosum is a defining feature of placental mammals, facilitating communication between the brain's hemispheres. Birds have different brain structures for interhemispheric communication.
Based on the analysis, combinations II and III are correct. Thus, the option listing II and III is the correct answer.
Always cross-reference both the feature and the example provided for each class to ensure accuracy.