A desert animal produces concentrated, paste-like nitrogenous waste with minimal water loss. What is the likely mode of excretion?
A. Osmotolism
B. Uricotelism
C. Ureotelism
D. Ammonotelism
Answer (2)
The correct mode of excretion for desert animals producing concentrated waste with minimal water loss is uricotelism, denoted as option B. Uricotelism involves the excretion of uric acid, which conserves water. This method is crucial for survival in arid environments.
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The likely mode of excretion for desert animals producing concentrated, paste-like nitrogenous waste is uricotelism (Option B).
Desert animals have adapted to their arid environments by developing ways to conserve water while still excreting waste products. One such adaptation is uricotelism, where the primary nitrogenous waste product is uric acid. Compared to other forms of nitrogenous waste like ammonia or urea, uric acid is less soluble in water and can be excreted as a semi-solid paste.
Why Uricotelism?
Water Conservation: Uric acid allows these animals to excrete nitrogenous waste with minimal water loss, which is crucial for survival in desert conditions where water is scarce.
Concentration Ability: Uric acid can be excreted in a highly concentrated form as a paste, reducing the need for water.
Comparison with Other Excretion Modes:
Ammonotelism (D): Involves excreting ammonia, which requires large amounts of water for dilution and is common in aquatic animals.
Ureotelism (C): Involves excreting urea, which requires more water than uric acid but less than ammonia, and is typical in mammals not primarily living in very arid conditions.
Osmotolism (A): This term does not refer to a recognized mode of excretion.
Therefore, uricotelism is the most efficient mode of excretion for desert animals like reptiles and birds living in dry regions, allowing them to maintain their water balance effectively.
