1 Why is homeothermy more metabolically expensive than poiki

1. Why is homeothermy more metabolically \"expensive\" than poikilothermy? Explain the relationship between the metabolic costs of homeothermy, ambient temperature and ability to gather sufficient food.

Solution

ANS:

Poikilothermy:

The internal body temperature of an organism can changes according to environmental temperature change.

Poikilothermy charecteristics:

Body Temperature  variable

Ectotherm

Metabolically cheaper

Lower caloric intake

Limits habitats

Thermoregulation mainly behavioral.

Ex: Reptiles and Amphibians.

Homeothermy:

In Homeothermic organisms, internal body temperature is stabled and it maintained by the thermoregulation mechanism. The body temperature is more or less constantly maintained over a range of environmental temperature.

Due to the thermoregulation mechanism homeothermy more metabolically \"expensive\" than poikilothermy

Homeothermy charecteristics:

Same body Temperature

Endotherm

Metabolically costly!

Large caloric intake

More habitat choice

Thermoregulation mainly physiological

Ex: Mammals

Poikilothermic and Homeothermy relationship:

Poikilothermic lack thermoregulatory mechanism, so the organism body temperature is variable. In Homeothermic organism body temperature is auto regulated by thermoregulatory mechanism

Homeotherms had high metabolic rate when compare with poikilotherms because of its complex circulatory and respiratory systems.

Poikilotherms had small body size than homeothermic. The internal thermoregulation counterparts, probably because it is more difficult to internally thermoregulate a larger body without mechanisms to do so.

The cell membrane of poikilothermic play a vital role in body temperature maintenance according to environment. It is because the fluidity of cell is determined by this membrane lipids and proteins. In cold water, membranes become less fluid and in high heat temperature however, defensive strategies involving heat shock proteins are more common.