Osmoregulation In different Environments.

 Osmoregulation in Different        Environment 

                      Marine 

Marine invertebrates: Most marine invertebrates are osmocoformers.

Hag fishes:

The hag fishes keep their énvrinment isotonic to the surrounding sea water.

Cartilaginous fishes:

Most of the cartilaginous fishes  maintain lower internal salt concentration than the sea water. Their kidneys and gills excrete salts for osmoregulation. Additionally, they also posses salt secreting organs like rectal glands. These fishes use active transport mechanism to remove salts against the osmotic concentration gradient

Urea retaining marine fishes: 

Some fishes have relatively low salts in the body fluid. But they retain urea in adequate concentration for making this fluid hypertonic to the sea water. Urea is harmful in high concentration. so these fish retain another chemical Called trimethylamine oxide. This compound protects the fishes against the harms of urea.

Boney fishes :

Bony fishes have formed from the fresh water ancestors But later, they become marine. They constantly lose water form their hypotonic body fluid into hypertonic environment. These fishes are adapted to drink a large amount of sea water. They excrete concentrated urine. So they excrete maximum salts but loss minimum water.

Fresh water

Fresh water animals constantly face the problem of flooding.So they lose salts. Fresh water protozoa like Amoeba. Paramecium pump out excess water by contractile-vacuole. Many fresh water fishes remove excess water by excreting large volume of very dilute urine. They compensate this loss of salt by these adaptations.

• They eat salt containing foods.
• Uptake salts by active transport through gills and skin.

Terrestrial environment 

The terrestrial animals loss water by evaporation. It leads to dehydration . It is major problem for the terrestrial animals. The arthopods and vertebrates have successfully adapted to terrestrial life. They have following adaptations to solve the problem of dehydration: 

1. The body surface of the terrestrial animals is covered with structures. These structures reduce the loss of water: 

Waxy exoskeleton of insects The terrestrial vertebrates have dead. multilayered skin. These layers of skin are composed of keratinized skin cells. 

2.They drink and eat moist foods to compensate the loss of water. 

3.These animals also show metabolic and behavioral adaptations. Some desert mammals like kangaroo rat survive without drinking water. It feeds on seeds of desert plants. These seed contains more carbohydrates. The metabolism of carbohydrates produces water. 

4. The terrestrial animals possess kidneys. Kidney absorbs most of the 

filtered water in the process of excretion. So they produce concentrated urine. 

5. These terrestrial animals have developed different methods to tolerate dehydration. The toleration of dehydration is called anhydrobiosis.