Does longevity differ between Homeothermic and Heterothermic Endotherms?

Does longevity differ between homeothermic and heterothermic endotherms?

Introduction

Birds and Mammals are endotherms because they obtain their body heat from cellular processes. A constant source of internal heat allows them to maintain nearly constant core temperature, despite the fluctuating environmental temperature. Core means body's internal temperature as opposed to the temperature near its surface. Most endotherms have bodies insulated by fur of feathers or hairs and large amount of fat (McFarlane, 1999). This insulation enables them to retain heat more efficiently and to maintain high core temperature. Endothermy allows animals to stabilize their core temperature so that biochemical processes and nervous system functions can proceed at steady high levels. Endothermy allows some animals to colonize habitats derived to ectotherms.

Discussion

Difference between ECO and Endotherms

Ecotherms derive most of their derive most of their body heat from the environment rather than from their own metabolism. They have low rates of metabolism and are poorly insulated. In general, reptiles, amphibians, fishes and invertebrates are ectotherms, although few reptiles, insects and fishes can raise their internal temperature. Eclotherms tend to move about the environment and find places that minimize heat or cold stress to their bodies. Birds and Mammals are endotherms because they obtain their body heat from cellular processes. A constant source of internal heat allows them to maintain constant core temperature, despite the fluctuating environmental temperature (Katz, 2002).

Most endotherms have bodies insulated by fur or feathers or hair and relatively large amount of fat.

Homeotherms and Heterotherms

Most endotherms are homeotherms (maintain constant body temperature) and most ectoderms are heterotherms (have variable body temperature). Some endotherms vary their body temperatures seasonally (e.g. hibernation), others vary it on daily basis.

Some humming birds and mammals (e.g. shrews) can only maintain high body temperature for a body mass so small that they cannot generate enough heat to compensate for the heat lost across their large surface area. Humming birds must devote much of the day to locating and sipping nector (a very high calorie food source) as a constant energy source for metabolism (Block, 1985). When not feeding, humming birds rapidly run out of energy unless their metabolic rates decrease considerably. At night humming birds enter a sleep like state called daily torpor and their body temperature approaches that of cooler surroundings, some bats also undergo daily torpor to conserve energy.

Difference Between Homeothermic and Hetrothermic

Scientific understanding of the multitude of existing regulatory regimes heat has evolved considerably since the original distinction between Homeothermic and Hetrothermic animals. For example, we know that Hetrothermic animals use all methods to adjust their internal temperature. There are also animals that belong specifically to any of the two categories (between hot bloods and cold bloods).

As follows (Heinrich, 1976):

The tuna and swordfish are very deep in the ocean, where the temperature is very cold. Swordfish are able to increase the temperature of their brains and their eyes, which allows faster eye movements when they hunt. Tuna, they are able to warm their whole body through a heat ...