Question

Match Column-I with Column-ll and select the correct option from the codes given below. Column-I Column-ll Nephridia (i) Crustaceans B. Malpighian tubules (ii) Annelids C Antennal gland (iii) Insects or Green glands (a) \(A-(i), B-(i i), C-(i i i)\) (b) \(\mathrm{A}-(\mathrm{iii}), \mathrm{B}-(\mathrm{ii}), \mathrm{C}-(\mathrm{i})\) (d) \(A \cdot(\) ii), \(B\) - (iii), C-(i) (d) \(\mathrm{A}-(\mathrm{ii}), \mathrm{B}-(\mathrm{i}) \mathrm{C}-(\mathrm{iii})\)

Short answer

A-(ii), B-(iii), C-(i), which corresponds to option (d).

Step-by-step solution

Identify the Functions of Each Item in Column-I

Understand what each organ in Column-I does: Nephridia are involved in excretion and osmoregulation in Annelids, Malpighian tubules are excretory organs found in Insects, and Antennal or Green glands perform excretory functions in Crustaceans.

Match Functions to the Corresponding Animal Groups in Column-II

Match each organ in Column-I with the appropriate animal group in Column-II based on their functions identified in Step 1. Nephridia are linked with Annelids (ii), Malpighian tubules with Insects (iii), and Antennal gland or Green glands with Crustaceans (i).

Identify the Correct Option from the Given Codes

From the options given, find the one that matches each item in Column-I with the correct animal group in Column-II. A correct match would be: A-(ii), B-(iii), C-(i).

Key concepts

Nephridia in Annelids

Annelids, a phylum of invertebrates that includes earthworms and leeches, possess a remarkable excretory system featuring nephridia. These tiny tube-like structures function in a manner akin to human kidneys, albeit on a simpler level.

Nephridia are tasked with the elimination of metabolic waste products and excess water, helping to maintain the internal fluid and electrolyte balance. Each segment of an annelid typically has a pair of nephridia, and their working begins with the funnel-like structure called the nephrostome, which collects excess fluids and waste from the coelomic cavity, the fluid-filled space that envelops the internal organs.

The process of filtration and reabsorption is critical, as it allows for the selective retention of useful substances like glucose and ions. The wastes are then transported to the nephridiopore, where they are expelled from the body. The regulation of water content through nephridia also serves as an osmoregulatory function, keeping the worm's body fluids at an optimal concentration.

Malpighian Tubules in Insects

Malpighian tubules are the cornerstone of the excretory and osmoregulatory system in many insects such as fruit flies and grasshoppers. Like nephridia in annelids, these tubules are crucial for waste removal, but they operate in a different fashion.

Typically located at the junction where the midgut meets the hindgut, these slender, blind-ended tubes float freely within the hemocoel, the insect's primary body cavity. Insects lack a centralized circulatory system, so their body cavity is filled with hemolymph, a fluid analogous to blood.

Malpighian tubules extract metabolic wastes like uric acid directly from the hemolymph and facilitate its conversion into a semi-solid form that is less toxic and more water efficient – a significant advantage for insects inhabiting dry environments. These waste products then pass into the hindgut, where they may be further processed before being expelled, minimizing water loss, which is a key aspect of an insect's survival strategies.

Antennal Gland in Crustaceans

Crustaceans, the diverse aquatic group that includes creatures like crabs, lobsters, and shrimp, rely on a unique structure known as the antennal gland (also referred to as the green gland in some species) for excretion and osmoregulation. Located in their heads, these glands are named for their proximity to the crustacean's antennae.

The antennal gland performs similarly to nephridia and Malpighian tubules by removing excess salts, water, and nitrogenous wastes from the blood. It typically consists of three main parts: the end sac, which filters the blood; a labyrinth, where selective reabsorption of valuable ions and molecules occurs; and a bladder that collects waste before its expulsion through a pore at the base of the antennae.

This excretory system plays a pivotal role in maintaining the osmotic balance for these organisms, particularly crucial for those that transition between freshwater and marine environments, where external salinity levels can differ dramatically.