What is enantiostasis and how is it different to homeostasis? (1 Viewer)

[leesh95]

I know the definition but I want to know what it actually is.
There are barely any resources available on this online and I'm very confused.
Also do osmoregulators do enantiostatsis and if yes then how? Or do they do homeostasis?

 

[LoveHateSchool]

So enantiostasis is the maintenance of metabolic and physiological functions in response to variations in the environment.
There are two types of organisms that carry out enantiostasis; osmoconformers and osmoregulators.

Osmoconformers: they conform to the surrounding environment by altering the concentration of their internal solutes. Their metabolic processes are able to tolerate any changes in salinity in their own body fluids and cells, a contrast to osmoregulators. An example of this includes Grey Mangroves (Avicenna Marina).

Osmoregulators: These organisms are unable to tolerate a range of salt concentrations in their body fluids and so avoid changes in their internal environment by keeping the solutes at an optimum level. Examples include fish that move away when salt change occurs, molluscs that close their shells etc.

It differs from homeostasis, as homeostasis is the maintenance of a constant internal environement. Enantiostasis is where an organism can maintain maintain its normal functioning despite the outside environment changing. It can do this whilst NOT maintaining homeostasis - e.g. the salt levels in an organism can increase (therefore not homeostatic ) as the tide comes into an estuary but it has mechanism so that its normal metabolic and physiological functioning can be maintained as per normal.

Homeostasis is it is detected as an internal change that is rectified through negative feedback whereas enantiostasis is to the external environment and doesn't counteract it in the same way as homeostasis.

 

[jnney]

Biology in Focus has a pretty indepth explanation for the concept of enantiostasis - probably should check that out.

Explanation for Enantiostasis:

There are some organisms in nature that are confronted with extreme fluctuations in their environments - e.g. those that live in an estuary, where during the high tide the salt concentration is significantly higher than the low tide. these changes happen on a daily basis. In order for organisms to survive these environmental changes (e.g. metabolic and physiological functions), they've evolved the mechanism of enantiostasis. Another example where organisms would have to employ enantiostasis is during flight (such as birds) where there are fluctuations between atmospheric pressure.

There are TWO methods in which enantiostasis can be carried out by organisms (note: they only fit into either one of the categories):

1. AVOIDING the changes
2. TOLERATING the changes


No.1 are your osmoregulators. They (i.e. an organisms metabolism and cell physiology) are unable to tolerate a wide range of salt + water concentrations in the body (internal environment), and so, they have mechanisms to avoid these changes. Hence, they keep their internal environment within an optimal level despite external fluctuations.

Here's an example: Let's think about Salmon. They are osmoregulators. Their survival is conducted by employing enantiostasis - i.e. avoiding changes in their internal environment. Hence, they constantly drink water to eliminate salts through gills when the tide is high (high concentration in salt water), and absorb water through gills and excrete dilute urine when the tide is low.

No. 2 are osmoconformers. They are different to osmoregulators in that they allow changes within their internal environment. This is because their internal environment - i.e. cell metabolism and physiology is able to tolerate extreme changes. Hence, they survive by altering the concentrations of internal solutes to match their surrounding environment.

Let's look at an example for osmoconformers: Fiddler crabs. In high salt concentrations within the external environment, Fidler crabs accumulate salt into its tissues until the same salt concentration is reached in its internal environment. But when the tide is low (comparably lower salt concentrations) salt is pumped out of its gills.


Something to note is that you are not required to know the terms 'osmoregulators' and 'osmoconformers'. You can simply class the two different ways organisms carry out enantiostasis by either 'avoiding' or 'tolerating' changes in response to fluctuations in the environment.


Difference between the two concepts: Homeostasis - a body's response to an internal change. Enantiostasis - a body's response to an external change. I'll get back to you for further clarification.

 

[nancyjose]

Enantiostasis is the ability of an open system, especially a living organism, to maintain and conserve its metabolic and physiological functions in response to variations in an unstable environment.
Homeostasis is the process by which the body attempts to maintain a state of stable physiological balance. The body needs to maintain homeostasis in order to stay alive. If you take a psychoactive drug, your body may attempt to bring itself back into this physiologic balance, and this may create a rebound effect.

 

[captainpigs]

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