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

Anomalies related to oesophagus and stomach, Anomalies Related to Oesophagu...

Anomalies Related to Oesophagus and Stomach   Let us discuss briefly the anomalies of oesophagus and stomach. These are summarised as  follows: Associated Problems  1)  P

Meaning of behaviour change communication, Behaviour change communication i...

Behaviour change communication is necessary as it ensures that the diabetic patient and their families have access to correct information about the disease, complications, treatm

Explain antibacterial activity, Antibacterial activity   Rifaximin reach...

Antibacterial activity   Rifaximin reaches high concentrations in the intestinal tract and is active in vitro against a broad range of enteropathogens, including ETEC, EAEC, Shi

What is the function of the skin in humans, Q What is the function of the s...

Q What is the function of the skin in humans? The skin is the external covering of the body. In humans its major functions are protection and perception of information from the

Therophytes - classes of life form, Therophytes - Classes of Life Form ...

Therophytes - Classes of Life Form These are annual plants of the summer season or of the favourable season. They complete their life cycles in a single favourable season and

How could an adult lose billions of cells, How can an adult lose billions o...

How can an adult lose billions of cells from all parts of the body each day and still survive?

Shifting cultivation - degradation of ecosystem, Shifting cultivation - Deg...

Shifting cultivation - Degradation of Ecosystem This method of cultivation is practised all over the globe, but is more prevalent in the tropical countries. In this practice a

Transcription in eukaryotes, The Eukaryotic transcription is more difficult...

The Eukaryotic transcription is more difficult than prokaryotic transcription. For example, in eukaryotes the genetic material DNA and therefore transcription is basically localize

Why are most ammoniotelic beings aquatic animals, Why are most ammoniotelic...

Why are most ammoniotelic beings aquatic animals? Aquatic animals, like crustaceans, bony fishes and amphibian larvae, usually are ammoniotelic since ammonia diffuses more easi

Health conditions, 2. Mr Konarski, 73 years old, lives in a high-level care...

2. Mr Konarski, 73 years old, lives in a high-level care facility. He has dementia of the Alzheimer''s type, osteoarthritis in both knees and ankles, and hypertension, which is con

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