Question 1.
Why don’t terrestrial animals and some aquatic animals just excrete dilute ammonia in liquid?This is because terrestrial animals and some aquatic animals such as frogs and turtles are ureotelic. This types of animals afford to excrete sufficient water to concentrate urea. Ammonia can be detoxify to form urea through the orrithine cycle in the liver. Urea is far less toxic compared to ammonia so can remain inside the body for a bit longer without causing illness to the animals.
Question 2.
Birds and mammals are the only vertebrates that can produce hypertonic urine [i.e. urine that is more concentrated than body fluids]. Why?Loop of henle is the main factor in which mammals and birds can produce hpertonic urine. this is becasue they have a nephron with long loop descends into medulla that produce more concentrated urine. Birds able to produce urine twice as concentrated as blood. this is due to in some birds like marine birds , they drink sea water and able to excrete salt from their salt gland which makes they have concentrated urine. Some of the moderately hypertonic urine also being delivered to the cloaca.
