Problem 118 - Objective Biology for NEET

Question

The mouth which has file-like rasping organ for feeding called radula is found in (a) Mollusca (b) Hemichordata (c) Echinodermata (d) Arthropoda

Step-by-Step Solution

Answer

The correct answer is (a) Mollusca. This is because the radula, a specific feeding organ, is found only in animals belonging to the phylum Mollusca.

Step 1: Understanding Animal Classification

First, understand the distinctive features of each phylum - Mollusca, Hemichordata, Echinodermata, and Arthropoda.

Step 2: Identifying Phylum with Radula

Identify the phylum to which an organ called radula is unique. The radula is a minute toothed, chitinous ribbon in mouth which is used for feeding. This is typically found in animals belonging to phylum Mollusca.

Step 3: Selecting the Correct Answer

Based on the understanding from Step 2, it can be concluded that Mollusca is the correct answer.

Key Concepts

Mollusca

Mollusca is a diverse phylum of animals known for their soft bodies, which are often protected by a hard shell. These creatures inhabit both aquatic and terrestrial environments, displaying a wide variety of forms and behaviors. Examples of mollusks include snails, clams, and octopuses.
Mollusks have several defining characteristics that set them apart from other animal phyla:

• A muscular foot used for movement
• A mantle that secretes the shell
• A unique feeding organ called a radula

Understanding these features can help you recognize members of the Mollusca phylum and distinguish them from other groups.

radula

The radula is a fascinating and unique feature found in many mollusks. It is a tongue-like organ with tiny, chitinous teeth arranged in rows. This file-like organ acts as a sort of grater, scraping food materials before they're ingested.

The radula allows mollusks to feed efficiently, adapting to different food sources:

• Herbivorous species use the radula to scrape algae and plant matter from surfaces.
• Carnivorous mollusks can use the radula to attack and consume other animals.

It's important to note that the radula is not present in all mollusks. However, the presence of a radula is often a key characteristic used to identify belonging to the Mollusca phylum.

feeding organ

Feeding organs play a crucial role in the survival and adaptation of various animal groups. In the context of mollusks, the radula serves as a specialized feeding organ, enabling these creatures to efficiently process food.

Understanding feeding organs improves our comprehension of animal adaptation:

• Different shapes and structures of feeding organs often reflect an animal's diet.
• In mollusks, the radula's design allows the scraping and slicing of food, adapting to diverse habitats and food sources.

By examining these organs, scientists can infer feeding behaviors and ecological niches of various species.

Echinodermata

Echinodermata is a distinct phylum of marine animals, well-known for their radial symmetry and unique water vascular system. This phylum includes starfish, sea urchins, and sea cucumbers, among others. Unlike mollusks, echinoderms do not have a radula.

Key Features of Echinodermata:

• They possess an endoskeleton made of calcareous plates.
• A water vascular system aids in movement and feeding.
• Their body symmetry usually exhibits five-part radial symmetry.

Although echinoderms do not possess a radula, their feeding methods are equally fascinating. For instance, many echinoderms use tube feet to grasp prey or filter particles from the water.

Arthropoda

Arthropoda is the largest phylum in the animal kingdom, encompassing an incredible diversity of species, including insects, arachnids, and crustaceans. These creatures are characterized by their segmented bodies, jointed legs, and exoskeletons.

Main Characteristics of Arthropoda:

• A chitinous exoskeleton that provides protection and support
• Segmented bodies with specialized segments for various functions
• Jointed appendages that include legs, antennae, and mouthparts

Unlike mollusks, arthropods do not possess a radula. Instead, they have various mouthparts that are adapted to their specific diets, such as mandibles for chewing or proboscises for sucking nectar.