Tolerance to cold and freezing temperatures, Biology

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.

Posted Date: 1/16/2013 4:58:46 AM | Location : United States







Related Discussions:- Tolerance to cold and freezing temperatures, Assignment Help, Ask Question on Tolerance to cold and freezing temperatures, Get Answer, Expert's Help, Tolerance to cold and freezing temperatures Discussions

Write discussion on Tolerance to cold and freezing temperatures
Your posts are moderated
Related Questions
Define the Post-Herbal Period? It is difficult to draw a sharp line of demarcation between the transition period, marked by various attempts of classification, all of which we

Nutrient stability as affected by processing of feeds Nutrient stability under normal conditions of storage and processing is one of the important factors determining the effe

Homologous series A homologous series can be illustrated as a group of compounds in which the several members have similar structural features and identical chemical propertie

Q. Fluids requirement in ulcerative colitis? Fluids: A liberal intake of fluid should be given to prevent dehydration. The passage of at least 1200 ml of urine indicates that a

Pyramid of Energy - Ecological Pyramids When we wish to compare the functional roles of the trophic levels in an ecosystem, an energy pyramid is probably the most informative.

The concentration of the tissue fluid, which bathes all cells in the body, is kept more or less constant. Why is this important? If the tissue fluid became more dilute, the ce

Briefly Explain about the Chromium? As you will go through this section, you will realize that compared to other minerals, the essentiality of chromium was recognized very late

what are the adaptations of amoeba

A normal healthy cell is bathed in a normal extracellular saline.  The plasma membrane of the cell contains voltage-gated sodium channels, sodium-glucose co-transporters, and sodiu

Q. Common causes related with angina pectoris? • The usual cause of angina is the narrowing of the major coronary artery due to atherosclerosis. • Systemic hypertension inc