Question

Malpighian tubules are the excretory organs in (a) Platyhelminthes (b) Cockroach (c) Pila (d) Ascaris

Short answer

The organism in which Malpighian tubules function as the excretory organs is the Cockroach.

Step-by-step solution

Understand Malpighian Tubules

Malpighian Tubules are organs for excretion and osmoregulation in insects and other terrestrial arthropods including insects, myriapods, and spiders.

Identify the Organism

Look at the options given: Platyhelminthes, Cockroach, Pila, and Ascaris. Only one of these organisms will have Malpighian Tubules as their excretory organ.

Match the Correct Organism

Among the options given, the Malpighian tubules function as the excretory organs in Cockroach, which is an insect. The other organisms have different excretory structures - flame cells in Platyhelminthes, nephridia in Ascaris, and kidney in Pila.

Key concepts

Excretory Organs in Insects

Insects, such as the cockroach, have a unique excretory system that is highly efficient in conserving water, a critical adaptation for terrestrial life. The Malpighian tubules are at the heart of this system. These tubules are thin, finger-like projections that branch off from the alimentary canal and float freely in the insect's body cavity.

Here's how they work: waste products are filtered out from the insect's blood (hemolymph) and passed into the tubules. These wastes are then converted into solid uric acid, which is less toxic and less soluble in water. This process is crucial as it helps to minimize water loss, allowing insects to thrive in dry environments.

Students studying NEET Biology need to remember that Malpighian tubules are specific to arthropods and are not found in other organisms listed in the options such as Planaria under Platyhelminthes, or Ascaris from the nematode family.

Osmoregulation in Arthropods

Osmoregulation is the process by which organisms maintain the delicate balance of water and salts in their bodies. Arthropods, which include insects and spiders, have evolved special structures like Malpighian tubules to manage this balance.

Malpighian tubules help arthropods by removing waste products from their blood, a process that also involves the regulation of ions and water. They effectively segregate the wastes into the digestive tract, where reabsorption occurs, ensuring that valuable water and salts are reclaimed and preventing dehydration.

For students gearing up for competitive exams like NEET, it's important to understand the relationship between excretory systems and the conservation of water, as it is a frequently covered topic. Knowing that arthropods use Malpighian tubules primarily for osmoregulation and nitrogenous waste removal provides a comprehensive insight into their survival adaptations.

NEET Biology

NEET, an acronym for National Eligibility cum Entrance Test, is a preeminent examination for students in India who wish to pursue undergraduate degrees in medical and allied fields. Biology is a fundamental part of the NEET syllabus, encompassing a wide array of topics including physiology, ecology, and genetics.

Students preparing for NEET should be well-versed in the anatomy and physiology of different organism systems, which includes understanding the role of excretory organs across various species. Questions like the one regarding Malpighian tubules often appear in the exam to test a student's knowledge on comparative anatomy and adaptive physiology of animals, which is critical for the NEET Biology section.

Topics such as these also serve as a bridge to more complex understanding of evolutionary biology, as they demonstrate how different species have evolved specific organs like Malpighian tubules to solve the same problem—waste excretion and osmoregulation—albeit in different environmental contexts.