Question

Birds convert ammonia to ________ for excretion. a. proteins b. urea c. uric acid d. nucleic acid

Short answer

Birds convert ammonia to uric acid for excretion, so the answer is c) uric acid.

Step-by-step solution

Understand the Question

The question asks what chemical birds convert ammonia into for the purpose of excretion. Birds have unique mechanisms for waste management in their bodies.

Recall Relevant Biological Processes

Ammonia is a waste product from protein metabolism. In many organisms, ammonia is converted to a less toxic form before excretion. In mammals, this is usually urea, a soluble compound excreted in urine.

Identify Birds' Excretion Process

Birds excrete nitrogenous wastes differently compared to many other animals. They convert ammonia into uric acid. Uric acid is less soluble in water and is excreted as a semi-solid paste, conserving water—an essential adaptation for birds.

Choose the Correct Option

Given the options: a) proteins, b) urea, c) uric acid, d) nucleic acid, the correct choice is the one that aligns with the excretion of a less soluble waste product. From Step 3, we know birds excrete uric acid.

Provide the Correct Answer

Based on your understanding, select option c) uric acid as the correct answer.

Key concepts

Uric Acid

Uric acid is a pivotal component in understanding how birds manage their waste. Unlike mammals, which convert ammonia into urea, birds produce uric acid to excrete nitrogenous waste. Uric acid's primary advantage lies in its solubility—or lack thereof. It is substantially less soluble in water compared to urea, meaning it can be excreted as a semi-solid. This is particularly beneficial for conserving water, a vital resource, especially for birds living in arid environments or during long flights where access to water might be limited.
In addition to conserving water, the semi-solid form of uric acid reduces the weight associated with liquid waste, which is crucial for flight efficiency. Essentially, uric acid helps birds thrive by allowing them to manage their waste efficiently, without the burden of carrying excess water weight.

Ammonia Conversion

The conversion of ammonia into a less toxic form is vital for all animals to thrive. In most organisms, ammonia, a toxic byproduct of proteins' breakdown, must be converted to avoid harm to the body. While mammals and amphibians typically convert ammonia into urea, birds convert it into uric acid. The conversion to uric acid is a complex, energy-intensive process but is incredibly effective in reducing water loss. Since uric acid is much less toxic and less soluble, birds are able to excrete it without requiring as much water as would be needed if they were excreting urea. This adaptation allows them to retain essential water, enabling survival in various habitats, from lush environments to dry deserts.

Nitrogenous Waste in Birds

Nitrogenous waste in birds primarily consists of uric acid, making their excretion system quite distinct. Nitrogenous waste results from protein metabolism, and birds have evolved a mechanism that allows them to handle this waste efficiently. While fish excrete ammonia directly into water and mammals convert it into urea, birds transform it into uric acid. This adaptation suits their specific needs for water conservation and the reduced weight of waste matter, essential traits that allow for more efficient flight and long-distance travel. The crystallized uric acid forms a paste that, along with feces, is expelled from the cloaca, which serves as the exit point for both waste types. This streamlined excretion process is a crucial component of avian physiology.

Excretory Adaptations in Birds

Birds have evolved unique excretory adaptations to optimize flight and water conservation. Their main adaptation is the conversion of ammonia to uric acid. This conversion is one part of a suite of adaptations that permit birds to inhabit a wide range of environments. Birds lack a bladder; instead, they utilize the cloaca for the disposal of both feces and uric acid. This adaptation reduces the need to carry extra weight associated with liquid urine, contributing to their ability to maintain lighter bodies suited for flight. Further, this method of excreting waste as a semi-solid paste allows birds to thrive in areas where water is scarce, ensuring their survival in diverse habitats. These excretory adaptations highlight the effectiveness of evolution in addressing the challenges faced by birds in their respective environments.