AP BIOLOGY

ANIMAL PHYSIOLOGY

OSMOREGULATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The nitrogenous waste that is mostly excreted by birds and reptiles is
A
Ammonia
B
Uric acid
C
Urea
D
Urine
Explanation: 

Detailed explanation-1: -In the body, nitrogenous wastes tend to generate poisonous ammonia, which must be expelled. Urea is excreted by mammals, while uric acid is excreted by birds, reptiles, and some terrestrial invertebrates.

Detailed explanation-2: -Like birds, reptiles excrete uric acid and also pay a high energetic price. Presumably the excretion of uric acid originally evolved in both groups to permit the laying of terrestrial eggs. Fish and amphibian eggs can pass water-soluble nitrogen compounds, ammonia and urea, into the water in which they are bathed.

Detailed explanation-3: -All reptiles excrete uric acid and thus do not need great amounts of liquid to rid themselves of nitrogenous wastes. All insectivorous lizards take in a large amount of water in the prey that they consume, and herbivorous lizards have salt glands for the active excretion of mineral salts.

Detailed explanation-4: -The two types of nitrogenous waste are urea and uric acid. Urea is the byproduct of ammonia in mammals, whereas uric acid is the byproduct of ammonia in birds and reptiles.

Detailed explanation-5: -Reptiles (e.g. lizards), birds, land snails and insects excrete nitrogenous wastes as uric acid in the form of pellet or paste with minimum loss of water and are called uricotelic animals.

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