PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Aquatic adaptations in Mammals.

PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Aquatic adaptations in Mammals.

1. Which of the following is a primary anatomical adaptation for reducing drag in aquatic mammals?

• a) Thick fur
• b) Presence of sweat glands
• c) Streamlined, fusiform body shape
• d) Long limbs

Correct Answer: Streamlined, fusiform body shape

2. The thick layer of subcutaneous fat found in cetaceans and pinnipeds that provides insulation is known as:

• a) Dermis
• b) Blubber
• c) Adipose tissue
• d) Keratin

Correct Answer: Blubber

3. The physiological response in marine mammals that slows the heart rate during diving is called:

• a) Tachycardia
• b) Hyperventilation
• c) Bradycardia
• d) Apnea

Correct Answer: Bradycardia

4. Which of the following mammals uses echolocation to navigate and hunt in water?

• a) Polar bear
• b) Manatee
• c) Walrus
• d) Dolphin

Correct Answer: Dolphin

5. The forelimbs of a whale are modified into:

• a) Paddles
• b) Flippers
• c) Fins
• d) Wings

Correct Answer: Flippers

6. A major challenge for marine mammals is preventing heat loss in cold water. This is a problem of:

• a) Osmoregulation
• b) Thermoregulation
• c) Respiration
• d) Buoyancy control

Correct Answer: Thermoregulation

7. The high concentration of this protein in the muscles of deep-diving mammals allows for oxygen storage:

• a) Hemoglobin
• b) Collagen
• c) Myoglobin
• d) Albumin

Correct Answer: Myoglobin

8. Which group of aquatic mammals is characterized by a horizontal fluke for propulsion?

• a) Pinnipeds (seals)
• b) Sirenians (manatees)
• c) Cetaceans (whales)
• d) Mustelids (otters)

Correct Answer: Cetaceans (whales)

9. The phenomenon where blood flow is restricted to vital organs during a dive is part of the:

• a) Dive reflex
• b) Vasoconstriction
• c) Vasodilation
• d) Countercurrent exchange

Correct Answer: Dive reflex

10. The nostrils of a dolphin are located on top of the head, forming a single blowhole. This is an adaptation for:

• a) Deep diving
• b) Streamlining
• c) Respiration while at the surface
• d) Echolocation

Correct Answer: Respiration while at the surface

11. Marine mammals drink minimal to no seawater. How do they obtain the necessary water for survival?

• a) They absorb water through their skin.
• b) They have specialized glands to process seawater.
• c) They get metabolic water from the fat and food they consume.
• d) They only consume freshwater fish.

Correct Answer: They get metabolic water from the fat and food they consume.

12. The specialized hairs on the muzzle of a walrus that are used for foraging on the seabed are called:

• a) Whiskers
• b) Vibrissae
• c) Bristles
• d) Tusks

Correct Answer: Vibrissae

13. The countercurrent heat exchange system in the flippers of seals helps to:

• a) Increase blood flow
• b) Minimize heat loss
• c) Facilitate oxygen absorption
• d) Maximize cooling

Correct Answer: Minimize heat loss

14. Which of the following is a key adaptation in marine mammals to tolerate pressure changes during deep dives?

• a) Large lungs that expand with depth
• b) Rigid rib cage
• c) Collapsible lungs and flexible trachea
• d) Inability to dive below a certain depth

Correct Answer: Collapsible lungs and flexible trachea

15. The specialized tail fin of a dolphin or whale is called a:

• a) Fluke
• b) Caudal fin
• c) Dorsal fin
• d) Pectoral fin

Correct Answer: Fluke

16. The eyes of aquatic mammals are adapted to see underwater by having:

• a) A flat cornea
• b) A spherical lens
• c) No eyelids
• d) Small pupils

Correct Answer: A spherical lens

17. Which of the following is an example of an amphibious marine mammal?

• a) Blue whale
• b) Sea otter
• c) Bottlenose dolphin
• d) Dugong

Correct Answer: Sea otter

18. The ability of a dolphin to hear and interpret sounds from far away in water is due to the presence of:

• a) External ears
• b) Specialized bones in the jaw
• c) A well-developed eardrum
• d) A large auditory canal

Correct Answer: Specialized bones in the jaw

19. Which adaptation allows seals to prevent their nostrils from filling with water during a dive?

• a) Muscular control of the nostrils
• b) A special valve in the nose
• c) Nostrils that close automatically
• d) They breathe through their mouth

Correct Answer: Nostrils that close automatically

20. In seals, the flattened forelimbs used for steering are known as:

• a) Paddles
• b) Flukes
• c) Flippers
• d) Pectoral fins

Correct Answer: Flippers

21. The reduction or complete loss of hindlimbs in cetaceans is an example of:

• a) Convergent evolution
• b) Vestigial structures
• c) Atavism
• d) Divergent evolution

Correct Answer: Vestigial structures

22. Which of the following marine mammals has a dense fur coat for insulation instead of blubber?

• a) Humpback whale
• b) Sea lion
• c) Polar bear
• d) Sea otter

Correct Answer: Sea otter

23. The elongated rostrum of a dolphin is a modification of the:

• a) Nasal bones
• b) Mandible
• c) Maxilla and premaxilla
• d) Frontal bone

Correct Answer: Maxilla and premaxilla

24. The function of the melon, a fatty organ in the forehead of toothed whales, is primarily for:

• a) Buoyancy control
• b) Sound focusing for echolocation
• c) Insulation
• d) Aggressive displays

Correct Answer: Sound focusing for echolocation

25. Which of these animals has a double-layered fur coat to trap air, providing buoyancy and insulation?

• a) Manatee
• b) Dugong
• c) River otter
• d) Walrus

Correct Answer: River otter

26. The primary sensory adaptation for a walrus foraging in murky arctic waters is:

• a) Echolocation
• b) Highly developed sense of sight
• c) Highly sensitive vibrissae
• d) Special olfactory receptors

Correct Answer: Highly sensitive vibrissae

27. The most fully aquatic group of mammals that never leaves the water is the:

• a) Pinnipeds
• b) Sirenians
• c) Carnivora
• d) Cetaceans

Correct Answer: Cetaceans

28. Which of the following is NOT an adaptation for thermoregulation in marine mammals?

• a) Countercurrent heat exchange
• b) Blubber
• c) Long, erect hair
• d) High metabolic rate

Correct Answer: Long, erect hair

29. A key difference in the respiratory system of a marine mammal compared to a terrestrial one is:

• a) Larger tidal volume and more efficient gas exchange
• b) Smaller lung capacity
• c) Use of gills for oxygen uptake
• d) Inability to hold breath for extended periods

Correct Answer: Larger tidal volume and more efficient gas exchange

30. The streamlined body of a dolphin and the body of a shark are examples of:

• a) Homologous structures
• b) Analogous structures
• c) Vestigial structures
• d) Divergent evolution

Correct Answer: Analogous structures

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