Zoology MCQs
Topic Notes: Zoology
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
1
Which group of fishes is characterized by a multi-layered skin containing mucous and sensory cells?
Answer:
cartilaginous fishes
Cartilaginous fishes (Chondrichthyes), such as sharks and rays, possess a unique skin structure. Their skin is covered in placoid scales and contains numerous mucous glands and sensory cells that help them navigate and detect environmental changes in their aquatic habitats.
2
Which structures found in the dermis of certain fish are known as placoid scales or denticles?
Answer:
dentils
Placoid scales, often referred to as dermal denticles, are characteristic of cartilaginous fishes like sharks. These structures are structurally similar to vertebrate teeth, consisting of a central pulp cavity surrounded by dentine and capped with enamel-like vitrodentine, providing protection and reducing drag.
3
How does the presence of a cartilaginous skeleton primarily assist cartilaginous fishes in their aquatic environment?
Answer:
swimming
Cartilage is lighter and more flexible than bone, which provides cartilaginous fishes (like sharks and rays) with significant advantages in buoyancy and maneuverability. This flexibility allows for more efficient swimming patterns and rapid changes in direction, which are essential for their predatory lifestyles and navigation through various depths in the water column.