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

Types of fats, FATS ARE OF TWO TYPES (a) Hard Fats They are t...

FATS ARE OF TWO TYPES (a) Hard Fats They are true fats which are solid at room temperature of 20 o C. It is due to presence of long chain saturated fatty acid

Mendel''s yellow peas, A plant grown from one of Mendel's yellow peas is se...

A plant grown from one of Mendel's yellow peas is selfed. Five progeny peas are obtained from this self and they are all yellow. If the original selfed plant had been homozygous, w

Processing of wastes from food industry, Processing of wastes from food ind...

Processing of wastes from food industry Various cellulosic wastes are available abundantly from food processing industry such as fruits and vegetable processing, breweries, st

Discuss in brief distant and contact osteogenesis, Q. Discuss in brief dist...

Q. Discuss in brief distant and contact osteogenesis? Three terms are used to describe individual aspects of bone formation process that occur at implants. They are Osteocondu

What is pancreatic lipase, What is Pancreatic lipase Pancreatic lipas...

What is Pancreatic lipase Pancreatic lipase  acts on  the dietary triacylglycerols after it has been incorporated into the mixed micelle  in  the  intestinal lumen. The lipa

Left atrio-ventricular, The left atrio-ventricular aperture in man is guard...

The left atrio-ventricular aperture in man is guarded by

Legume - development of seeds, Legume - Development of seeds Outer epi...

Legume - Development of seeds Outer epidermis of the ovary usually forms the exocarp of the leguminous pod. Next few cell layers constitute the mesocarp with thick-walled pare

Describe about development of sexual maturity in children, Briefly Describe...

Briefly Describe about Development of Sexual Maturity in Children? Sexual maturity develops along with growth spurt in adolescence. In girls, growth stops on attaining menarche

Peroxisome and lysosome, e use itwhat is difference between peroxisme and l...

e use itwhat is difference between peroxisme and lysosome what is function of it and where w

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