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

Cnidaria and platyhelminthes - larval forms, Cnidaria and Platyhelminthes -...

Cnidaria and Platyhelminthes - Larval forms Cnidaria The common larval stage that is found in cnidarians is the planula which forms following gastrulation. The planula is

Veterinary medicine, Veterinary medicine Veterinary medicine is a branc...

Veterinary medicine Veterinary medicine is a branch of science that deals with diagnosis, treatment and control of diseases in animals such as livestock, domesticated animals,

Define rna synthesis , The general mechanism of RNA synthesis by these euk...

The general mechanism of RNA synthesis by these eukaryotic RNA polymerases is the same as for the prokaryotic enzyme that is: ?   The initiation  of RNA synthesis  by RNA polyme

Describe the technique of food processing, Technique of food processing ...

Technique of food processing Freezing is another ancient technique of food processing, which allows the transportation of perishable food items for long distances from producti

Coronal disassembly-endodontics principles and practice, Coronal Disassembl...

Coronal Disassembly -If the existing restoration functionally designed well fitting and esthetically pleasing , -The access the pulp chamber during retreatment is better app

Metabolism of fructose, Fructose is an abundant sugar in the human diet; su...

Fructose is an abundant sugar in the human diet; sucrose (table sugar) is a disaccharide that when hydrolyzed yields glucose and fructose and fructose is also a major sugar in hone

What are the vascular bundles, What are the vascular bundles? How does conf...

What are the vascular bundles? How does configuration of the vascular bundles within the stem differentiate monocots from dicots? The Vascular bundles are segments of xylem and

Major renal processes that combined produce urine, Q. What are the three ma...

Q. What are the three major renal processes that combined produce urine? Urine is made by the occurrence of three processes in the nephron that are tubular resorption, glomerul

Fats requirement in diabetes, Q. Fats requirement in diabetes? Fats: Th...

Q. Fats requirement in diabetes? Fats: The total fat recommended by WHO is less than 30% of the total calories. However in view of the widely prevalent Asian paradox in India,

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