Question

Primary function of enternephric nephridia of Pheritima is (a). osmoregulation (b). excretion of nitrogenous waste (c). respirations (d). locomations

Short answer

The primary function of enteronephric nephridia of Pheritima is (a) osmoregulation.

Step-by-step solution

Understanding the primary functions of nephridia

Nephridia are tubular excretory structures in earthworms that filter fluids from the coelom. They perform two main functions: excretion and osmoregulation. Excretion involves removing nitrogenous waste from the body, while osmoregulation pertains to regulating the water and ionic balance in the organism.

Identifying the correct option

In the given options, osmoregulation and excretion of nitrogenous waste are both functions of nephridia. Since the question specifies 'primary function', it is necessary to determine which of these is the foremost role of nephridia in Pheretima (earthworms).

Choosing the best answer

The primary function of enteronephric nephridia in earthworms, including the genus Pheritima, is osmoregulation. Enteronephric nephridia regulate the composition of body fluids and maintain water balance, which is crucial for survival in their moist habitat.

Key concepts

Osmoregulation in Earthworms

Osmoregulation is a vital physiological process in earthworms, ensuring the balance of water and electrolytes in their body. Earthworms, such as those from the genus Pheritima, live in environments that can be considerably moist. Through the process of osmoregulation, earthworms control the amount of water and ions in their internal fluids to maintain a stable internal environment. This balance is crucial as it allows earthworms to adapt to the varying moisture levels in soil without suffering from cellular damage or dehydration.

This process is centralized in their nephridia, which act much like human kidneys filtering out excess water, salts, and nitrogenous wastes from their blood. Nephridia are exquisitely adapted to absorb, secrete, and excrete fluids as necessary to keep the internal environment of the earthworm stable, functioning efficiently even in the varying soil conditions where Pheritima species are commonly found.

Nitrogenous Waste Excretion

Nitrogenous waste excretion is another critical function of the nephridia in earthworms. As in many living organisms, metabolic processes in earthworms result in the production of nitrogenous wastes such as ammonia, urea, and uric acid. The excretion of these harmful substances is essential for the maintenance of cellular health. The nephridia filter these wastes from the coelomic fluid, a process that runs parallel to osmoregulation.

In Pheritima and other earthworms, this waste is ultimately converted into a less toxic form and expelled through the body wall or at the terminal ends of their bodies. The proper functioning of nephridia in dealing with these wastes ensures the earthworm's metabolic processes can continue unhindered by the accumulation of toxic substances.

Enteronephric Nephridia

Enteronephric nephridia are a specialized type of nephridia found in certain earthworms including those in the genus Pheritima. They are characterized by their connection to the digestive tract. Unlike other nephridia that may release waste outside the earthworm's body, enteronephric nephridia open into the gut, allowing for the direct excretion of waste into the digestive canal. This method is particularly efficient for terrestrial life as it consolidates waste excretion and reduces water loss, a crucial benefit for earthworms which typically have to conserve moisture.

The functional significance of enteronephric nephridia lies in their contribution to both osmoregulation and the excretion of nitrogenous waste. Their strategic placement in the body plan of Pheritima is a testament to the earthworm's evolutionary adaptations to manage their internal environment effectively.

Pheritima

Pheritima is a genus of earthworms that exemplifies the incredible adaptability of these organisms to diverse and fluctuating environmental conditions, largely due to their efficient osmoregulatory and excretory systems. Key features of Pheritima earthworms include their elongated, segmented bodies and the presence of specialized nephridia that aid in essential physiological processes like moisture regulation and waste removal.

Understanding how Pheritima adapt to their habitat provides insights into evolutionary adaptations among earthworms. Their ability to maintain water balance and efficiently remove metabolic waste allows these earthworms to thrive across various soil types, contributing to their role as 'ecosystem engineers' in enhancing soil fertility and structure.