Question

Which one of the following groups of animals is homeothermic?
A) Reptiles
B) Amphibians
C) Birds
D) Fishes

Answer 1

The word homeothermic originates from Greek homeo (similar) +‎ thermic (heat). Homeothermy is a phenomenon that is performed in “warm-blooded” animals.

Complete Answer:
Homeothermy is thermoregulation that maintains a stable internal body temperature regardless of external influence.

1. Reptiles can adjust their own body temperature according to the surrounding temperature and therefore are called poikilothermic animals. E.g.- Frog, Snake, Turtle.
2. Amphibians are poikilothermic as well, which means that they cannot regulate their own body temperatures internally.
3. Birds and animals can perform homeothermy therefore they are the only homeotherms in the animal kingdom.
4. Fishes are poikilothermic as they have no control over their body temperature and their core body temperature can fluctuate broadly.

Additional Information: Thermoregulation is a process that allows your body to maintain its core internal temperature. All thermoregulation mechanisms are designed to return your body to homeostasis. This is a state of equilibrium. Many factors can affect your body’s temperature, such as spending time in cold or hot weather conditions. If the internal temperature of a body drops or rises outside of the normal range, the body will take steps to adjust it. This process is known as thermoregulation. It can help avoid or recover from potentially dangerous conditions, such as hypothermia.

Thus, the correct answer is option C (Birds).

Note: Homeothermy obtained from endothermy is a high energy process. A major disadvantage of this is that when outside temperature is very low, the energy expenditure to maintain body temperature increases energy uptake and may lead to starvation and death.