How do the poikilotherms adapt to a cold weather?
In poikilotherms, exposure to cold stress or heat shock can alter membrane properties such that, unless they are corrected quickly, damage and, possibly, death can result. Low temperature stress is countered by modifying membrane lipids such that their average transition temperature is lowered.
Can poikilotherms survive cold climates?
Poikilothermic, or cold-blooded animals face a risk of death due to cold or freezing over the winter and have evolved multiple strategies for survival. Other poikilotherms manage to endure temperatures below 0°C.
How do poikilotherms maintain temperature?
Homeotherms maintain their body temperature within a narrow range, while poikilotherms can tolerate a wide variation in internal body temperature, usually because of environmental variation. Heat can be exchanged between environment and animals via radiation, evaporation, convection, or conduction processes.
What is one thing that all poikilotherms have in common?
Poikilotherm animals must be able to function over a wider range of temperatures than homeotherms. The speed of most chemical reactions vary with temperature, and in order to function poikilotherms may have four to ten enzyme systems that operate at different temperatures for an important chemical reaction.
How does the poikilotherm adapt to the environment?
Poikilotherms, which represent most of the organisms on Earth, have to survive and adapt to environmental stresses. One of the most important of the latter is temperature change. Such alterations lead to changes in membrane lipid order and, in the case of elevated temperatures, may cause protein unfolding and denaturation.
How is low temperature stress countered in poikilotherms?
Low temperature stress is countered by modifying membrane lipids such that their average transition temperature is lowered. There are various ways in which this can be achieved but an increase in fatty acid unsaturation is the most common.
What kind of animal is a poikilotherm?
It is this distinction that often makes the term “poikilotherm” more useful than the vernacular “cold-blooded”, which is sometimes used to refer to ectotherms more generally. Poikilothermic animals include types of vertebrate animals, specifically fish, amphibians, and reptiles, as well as a large number of invertebrate animals.
What happens to lipid order in a poikilotherm?
Lowering the ambient temperature of poikilotherms is likely to cause an increase in membrane lipid order. Because of the mixture of lipid classes and lipid molecular species in biological membranes, this will mean that one or more of these molecular species will be below its transition temperature (Tc).
