Question

Differentiate between Osmoconformers and osmoregulators.

Answer 1

The aquatic organisms are subjected to varying degrees of salinity or salt tolerance, osmotic fluctuation in accordance to the water. The organisms also face problems in terms of altering the conditions of the body as that of their surroundings. They must maintain the correct concentrations of solutes and amount of water in their body fluids for proper survival.

Complete Solution:
In the aquatic organisms, there is a constant pressure to maintain the levels of water fluid as well as the measure of solute in the fluids. This condition is also maintained in terms of the blood as well as the urine produced by them. The mechanism of active regulation of osmotic pressure in the body fluids of an organism is termed as osmoregulation. It is an important property and is very useful in maintaining balance of body fluids and concentration of electrolytes or salts present in the solution. It prevents the body fluids from becoming too diluted or too concentrated and both of the cases are harmful to the organism.

During the osmosis, osmotic pressure causes water to enter to the solution at higher osmotic pressure. To prevent this situation or to counteract this problem of osmotic pressure, aquatic organisms have evolved certain mechanisms. These mechanisms help the organisms to survive in the high salt containing environment like in the marine habitats.

Two major types of mechanism which are involved in maintaining the osmoregulation are – osmoconformers and osmoregulators.

Osmoconformers are the type of organisms which are capable of matching their body osmolarity with that of their environment. They have the tendency to decrease or increase the osmolarity of their body in accordance to the environment in which they are present. The process of maintaining the salt concentration of their body fluids may occur passively or can be initiated actively. They maintain an internal environment that is mostly isotonic to the outer environment. This property means that the osmotic pressure of their body fluids are equal to the osmotic pressure of the environment. They tend to spend only very little amount of body energy on maintaining the osmotic balance of their body. The marine invertebrates are mostly osmoconformers.

Another type of mechanism to regulate the levels of salts in the body fluids through the process of osmoregulation. The organisms that employ this mechanism are known as osmoregulators. They actively control the salt concentrations despite the changes of salt concentrations of the external environment. In presence of less salt in the environment the gills of the fishes actively take up salt from the surroundings and they produce a very hypotonic or dilute urine to expel all the extra water. In marine fishes, they will produce a concentrated urine to expel out the excess salts and retain water. In cartilaginous fishes such as sharks, store large concentrations of urea in the body to attain proper levels of osmolarity.

Note: Osmoconformers are the organisms that match their body fluids with that of their environment by both active and passive ways. They constitute most of the invertebrates. These types of organisms expend less of their body energy to maintain the level of salts in the body as related to the environment. The osmoregulatory are primarily the fishes who have to maintain an level of equilibrium with that of the salt level of the surrounding