Question

freshwater and saltwater fish are exposed to opposite osmotic problems. are freshwater fish hyperosmotic or hypoosmotic to their environment? please also explain water and salt diffusion direction by simple osmosis in freshwater fish.

Answer 1

Freshwater fish are hyperosmotic to their environment, absorbing water by osmosis and managing excess by excreting diluted urine, all to maintain osmotic homeostasis.

Step-by-step explanation:

Freshwater fish are hyperosmotic to their environment, which means that the concentration of salts (ions) in their bodies is higher than in the surrounding freshwater. Consequently, water naturally diffuses into the fish through osmosis because water tends to move from areas of lower solute concentration (the freshwater environment) to areas of higher solute concentration (inside the fish). To cope with this, freshwater fish actively take in salts through their gills and excrete large volumes of diluted urine to rid themselves of the excess water that has entered their bodies. This process is crucial for maintaining their osmotic homeostasis, as it helps balance their internal salt and water levels despite the hypotonic nature of their environment.