Question

Maintenance of a relatively high and stable body temperature is considered a hallmark of endothermy. How is it achieved and supported? Endothermy comes with considerable benefits, but also at a steep cost. What are the advantages and disadvantages of being endothermic? Explain in detail. Provide a hypothetical scenario (including specific physiologic modifications) how endothermy might have evolved in a vertebrate taxon from an ectothermic ancestor

Answer 1

Endothermy -

Endothermy is achieved when the body is able to conserve heat to maintain a stable body temperature by internally generating enough heat to do so. A stable temperature is achieved by maintaining the right balance between the amount of heat generated internally through the metabolic processes at a high rate and the amount of body heat which is lost or exchanged to the external environment. A high metabolic rate in the endotherms is due to numerous mitochondria which generate ATP. The body of these endotherms is adapted to reduce the loss of heat. These adaptations differ in different species which assist them to conserve heat. Some of these adaptations are vasoconstriction of blood vessels and having a thick layer of subcutaneous fat.

Advantages of being endothermic -

• More stamina due to high metabolic rate.
• Rapid muscle activity.
• Waste generation is quicker.
• Adapt to winters by hibernating.
• Less vulnerability to temperature fluctuations.
• Strong immune system.

Disadvantages of being endothermic -

• Endotherms need more food supply to maintain body temperature.
• Face difficulty to survive in adverse food shortage due to minimum food storage.

Evolvement of endothermy -

Endothermy might have evolved in a vertebrate taxon from an ectothermic ancestor by undergoing certain modifications such as the

• Redistribution of fat bodies
• Adjustment of metabolic rate.
• Increasing the number of mitochondria in cells.
• Modification in the rate of blood flow in the body.
• Insulation in the body to reduce heat loss.
• Achieving the temperature tolerance ability by thermoregulation.