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

What is a community, What is a community? What is the difference between th...

What is a community? What is the difference between the concepts of community and population? A community is a set of populations of living beings that live in the similar regi

Explain about osseointegration, Explain about Osseointegration Osseoint...

Explain about Osseointegration Osseointegration is regarded as the process of direct bone apposition on implant surfaces where the bone in contact with the implant later underg

Neurophysics Assignment Help, What is Neurophysics Neurophysics is the ...

What is Neurophysics Neurophysics is the field of biophysics dealing with nervous system. Neurophysics covers a extensive spectrum of phenomena from molecular & cellular mechan

What is consanguineal marriage, What is consanguineal marriage? Why is the ...

What is consanguineal marriage? Why is the appearing of genetic disease more probable in the offspring of a consanguineal marriage? Consanguineal marriage is the marriage among

Discuss about human ears, Ears We have a pair of ears. Each ear has thr...

Ears We have a pair of ears. Each ear has three parts - external, middle and inner ear. The function of the middle ear is transmission of sound waves from external to inner ear

Explain pure culture techniques, Explain Pure Culture Techniques We lea...

Explain Pure Culture Techniques We learnt the techniques involved in sub-culturing, i.e., the process involved in transfer of culture from one medium to another or transfer of

Describe the principles of dna sequencing, The ability to sequence DNA has ...

The ability to sequence DNA has led to a revolution in molecular biology. a) Describe the principles of DNA sequencing. b) A single sequencing reaction yields at best 1500 ba

Digestion in coakroach, Awhat is the function of malpigrium tubulessk quest...

Awhat is the function of malpigrium tubulessk question #Minimum 100 words accepted#

Determine the term epitheliomuscular cell, Determine the term Epitheliomusc...

Determine the term Epitheliomuscular cell. Cells which line outer surface of cnidarians. These cell have two functions: first is to form the outer body covering of animal, seco

Principles of doppler echocardiography, Doppler echocardiogaphy is based on...

Doppler echocardiogaphy is based on  the Doppler effect, which was  described by  the Austrian phy$icist Christian Doppler in  1842. The Doppler effect states that sound frequency

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