Question

Assertion: Cockroach is uricotelic Reason: Fat bodies, nephrocyte and urecose glands help in excretion in cockroach

Short answer

The assertion that a cockroach is uricotelic is correct. The reasoning is partially correct, as the excretory system of cockroaches consists of fat bodies and nephrocytes, but not urecose glands.

Step-by-step solution

Understand Uricotelism

Uricotelism is a method of excretion where the primary substance being expelled is uric acid. This is common in birds, terrestrial reptiles, and insects. So the assertion that a cockroach (being an insect) is uricotelic is correct.

Understanding the Components of the Cockroach’s Excretory System

The excretory system of a cockroach comprises of the fat bodies, nephrocytes, and malpighian tubules, not urecose glands. Fat bodies act as a storehouse for uric acid. Nephrocytes are specialized cells that help in removing nitrogenous wastes. So parts of the reason given are correct.

Settling the Assertion and Reasoning

While the assertion that a cockroach is uricotelic is correct, the reasoning presented is partially correct. The cockroach's excretory system indeed comprises fat bodies and nephrocytes, which contribute to excretion. However, urecose glands are not part of the cockroach's known excretory system.

Key concepts

Uricotelism

Uricotelism refers to the biological process where organisms expel nitrogenous waste in the form of uric acid. This process is most often seen in organisms such as birds, reptiles, and insects like cockroaches. Uric acid is a relatively less toxic form of nitrogen waste compared to ammonia and urea, which is why it is advantageous for certain species. Since uric acid is not very soluble in water, it allows organisms to conserve water by excreting waste in a semi-solid paste rather than a dilute liquid. This adaptation is particularly useful for terrestrial animals that must conserve as much water as possible due to the risk of dehydration.

Cockroach Excretory System

The excretory system of a cockroach is an intricate network designed to efficiently eliminate nitrogenous wastes. It consists of several key components:

• Fat bodies: These structures act as storage for nutrients and are also involved in the storage of uric acid before it is excreted.
• Nephrocytes: Specialized cells that help filter out waste products from the hemolymph, which is the cockroach's version of blood.
• Malpighian Tubules: Critical in filtering nitrogenous wastes and converting them into uric acid.

Together, these components work to maintain internal homeostasis by regulating the levels of waste and conserving water. Note that urecose glands mentioned in some contexts are not part of the cockroach's excretory system.

Malpighian Tubules

The Malpighian tubules are vital components of the cockroach's excretory system. These long, thread-like structures extend into the body cavity of the cockroach and are instrumental in nitrogenous waste management. They function much like kidneys, extracting waste materials from the hemolymph. The waste is then converted into uric acid which is transferred to the digestive tract to be expelled. The Malpighian tubules can efficiently conserve water by reclaiming most of it during the waste processing phase. This ability is crucial for the cockroach's survival in dry environments as it prevents dehydration while ensuring that toxic waste substances are effectively processed and excreted. In summary, the Malpighian tubules play a central role in maintaining metabolic balance in cockroaches.

Nitrogenous Waste Removal

Nitrogenous waste removal is a key biological function necessary for the survival of organisms. Insects like cockroaches have adapted to efficiently manage this process, ensuring metabolic waste does not accumulate to toxic levels. The primary nitrogenous waste product in cockroaches is uric acid, which is less toxic and requires less water for excretion compared to other waste products like ammonia or urea. Waste is first filtered from the hemolymph by the Malpighian tubules. From there, it passes into the digestive system, where any remaining water is reabsorbed, leaving behind concentrated uric acid to be excreted. This method is highly efficient and helps cockroaches thrive in environments where water is scarce, highlighting their evolutionary success among terrestrial insects.