Tolerance to cold and freezing temperatures, Biology

Assignment Help:

Tolerance to Cold and Freezing Temperatures

In the earlier section you have been studying about tolerance of animals to high temperature. Now in this subsection we will study about tolerance to cold and freezing temperatures. The effects of low temperature are equally perplexing as those of high temperature. Some organisms can tolerate extensive freezing but most animals cannot. Animals that live in '4 temperature and cold regions are often exposed to long periods of winter temperatures that are far below the freezing point of water. Survival of ectothermic animals at such subzero temperature depends upon the physiological and biochemical characteristics that can be described as cold hardiness. An animal can develop cold hardiness either by developing capacity for freeze tolerance or by avoiding ice formation even if exposed to temperatures as low as -40°C to -50°C. The latter are regarded as freeze intolerant.

The intertidal marine invertebrates of colder zones are freeze tolerant in the sense that they survive extensive ice formation within their bodies. Many other animals also survive in spite of extensive ice formation. For example, midge Chironomous larva from Alaska can be frozen and thawed repeatedly without injury. Several species of insects are known to contain high concentration of glycerol in their body fluids. It is well-known that glycerol protects red blood cells and mammalian spermatozoa from injury caused by freezing. Therefore, glycerol is widely used for this purpose and samples of human or bull sperm can be kept frozen and viable for several years using glycerol. Without such treatment, freezing is Iethal, to sperms. Only a few vertebrates tolerate extensive ice formation. Birds and mammals however, are not known to tolerate freezing.


Related Discussions:- Tolerance to cold and freezing temperatures

Admission procedure - nursing, Admission Procedure   From the time  the...

Admission Procedure   From the time  the child and his family enter the hospital doors, the admission procedure should be carried out in a friendly and efficient manner. Admiss

Fats requirement in chronic diarrhoea, Q. Fats requirement in chronic diarr...

Q. Fats requirement in chronic diarrhoea? Total amount of fat may be restricted as its digestion and absorption is compromised. In order to increase on the calorie density of t

Production of rare hybrids, Production of Rare Hybrids Hybridization ...

Production of Rare Hybrids Hybridization is a well established plant breeding procedure to obtain superior plants by combining useful characters distributed in different plan

The best describes the acid properties of guanine, Which statement best des...

Which statement best describes the acid/base properties of guanine? -at pH, guanine will be negatively charge -at pH, guanine will be neutral -it will be an effective buff

Excretory system, what is the excretory organ in protozoa?

what is the excretory organ in protozoa?

Explain the functions of consciousness, Q. Explain the Functions of Conscio...

Q. Explain the Functions of Consciousness? Consciousness allows individuals to be aware of his/her surrounding, thereby defining the context and removing ambiguities. Simplific

Digestion of fats, Digestion of fats   A.  Production of bile salts in ...

Digestion of fats   A.  Production of bile salts in the liver and the secretion of those bile salts into the small intestine.   B.  Production of lipase in the pancreas and

Explain the evolution of the vascular plant body, Explain the Evolution of ...

Explain the Evolution of the Vascular Plant Body? Vascular Plant anatomy reflects adaptation to life on land. In an aquatic environment, the photosynthetic surfaces are support

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd