Explain why aquatic amphibians constantly take on water but lose ions to their environment. List the energy saving adaptations that help aquatic amphibians manage the challenges of living in a dilute environment as efficiently as possible. Why isn\'t the production of uric acid an adaptation of aquatic amphibians? Solution 1. Aquatic amphibians living in fresh water contain hypertonic body fluids and due to this they take up more water to dilute the tissue fluids and lose ions to their environment so that they can maintain osmolarity of body fluids with surrounding aquatic environment. 2. Amphibians living in hypoosmotic environments have some adaptations to maintain osmolarity of body fluids similar to surroundings.The osmolarity of body fluids of amphibians are 250moSm. This concentration reduces the stress on fnction of the kidneys. The osmosis taking place through skin uptake less amounts of water and reduces the function of kidneys in eliminating excess water and to maintain body homeostasis. Amphibians do not contain loop of Henle in their nephrons and an intermediate tubule connects the proximal and distal tubules. This reduces the amount of urine to be excreted. The ions like Na+ and Cl- are reabsorbed through active transport and against an electrochemical gradient. The Na+ ions are also reabsorbed across the bladder wall. The high water consumed is excreted successfully by these adaptations while retaining the ions. 3. Production of uric acid as nitrogenous waste is observed in reptiles and birds but not in aquatic amphibians. Processing of uric acid as waster requires little water but lot of energy. Aquatic amphibians excrete ammonia which requires lot of water with little expenditure of energy. Ammonia is toxic to body in high concentrations. Therefore, amphibians excrete ammonia through urine because they consume more water and can retain ions and spend less energy..

1. Explain why aquatic amphibians constantly take on water but lose ions to their environment.
List the energy saving adaptations that help aquatic amphibians manage the challenges of living
in a dilute environment as efficiently as possible. Why isn't the production of uric acid an
adaptation of aquatic amphibians?
Solution
1. Aquatic amphibians living in fresh water contain hypertonic body fluids and due to this they
take up more water to dilute the tissue fluids and lose ions to their environment so that they can
maintain osmolarity of body fluids with surrounding aquatic environment.
2. Amphibians living in hypoosmotic environments have some adaptations to maintain
osmolarity of body fluids similar to surroundings.The osmolarity of body fluids of amphibians
are 250moSm. This concentration reduces the stress on fnction of the kidneys. The osmosis
taking place through skin uptake less amounts of water and reduces the function of kidneys in
eliminating excess water and to maintain body homeostasis. Amphibians do not contain loop of
Henle in their nephrons and an intermediate tubule connects the proximal and distal tubules. This
reduces the amount of urine to be excreted. The ions like Na+ and Cl- are reabsorbed through
active transport and against an electrochemical gradient. The Na+ ions are also reabsorbed across
the bladder wall. The high water consumed is excreted successfully by these adaptations while
retaining the ions.
3. Production of uric acid as nitrogenous waste is observed in reptiles and birds but not in aquatic
amphibians. Processing of uric acid as waster requires little water but lot of energy. Aquatic
amphibians excrete ammonia which requires lot of water with little expenditure of energy.
Ammonia is toxic to body in high concentrations. Therefore, amphibians excrete ammonia
through urine because they consume more water and can retain ions and spend less energy.