SSC Selection Post 2025 PYQ — Question 2

Correct Answer

Endotherms

Explanation

Endotherms are animals that are capable of maintaining and regulating their body temperature internally through metabolic processes, regardless of the temperature of the surrounding environment. These animals are also commonly referred to as 'warm-blooded' animals. They generate heat from within their bodies by burning food energy, which allows them to remain active in a wide variety of climates, including very cold regions. Mammals and birds are the primary examples of endotherms.

The other options listed describe different classifications of animals that do not possess internal temperature regulation of this type. Ectotherms (commonly called 'cold-blooded' animals) rely primarily on external environmental heat sources, such as sunlight, to regulate their body temperature; reptiles, fishes, and amphibians fall into this category. Amphibians are a specific class of vertebrates that live both on land and in water, and they are ectothermic. Invertebrates are simply animals that lack a backbone or vertebral column, which is a structural classification rather than a thermoregulatory one.

Key Points

Endotherms possess high metabolic rates because they require a continuous supply of energy to generate internal body heat. They often have insulating structures like fur, feathers, or fat layers to prevent heat loss in cold environments. This internal regulation allows endotherms to maintain consistent cellular and physiological functions, making them highly adaptable to diverse ecological niches.

Additional Facts

While endotherms have the advantage of staying active in freezing environments, this strategy comes at a high energetic cost. An endotherm needs to consume significantly more food than an ectotherm of the same size just to maintain its basal metabolic rate. For example, a mammal might require ten times more food energy than a reptile of similar weight. When food is scarce, some endotherms enter states of torpor or hibernation to lower their metabolic rate and save energy.

Important Questions and Answers

Question: Which biological processes primarily generate the heat necessary for thermoregulation in endothermic animals?

Answer: Internal body heat in endotherms is primarily generated through cellular metabolism, specifically via the breakdown of nutrients during cellular respiration and mechanisms like shivering thermogenesis.

Question: What is the main ecological advantage that endotherms have over ectotherms?

Answer: The main advantage is the ability to remain active, hunt, and reproduce in extreme or rapidly changing environmental temperatures, including cold polar regions and nocturnal environments.