Question

Water enters through minute pores in the body wall into central cavity in sponges. These minute pores are known as (a) Osculum (b) Ostia (c) Spongocoel (d) Any of the above

Short answer

The correct answer is (b) Ostia.

Step-by-step solution

Understanding the Exercise

This is a direct question where you are asked to identify what the minute pores through which water enters into the central cavity also known as spongocoel in sponges are called. You have been provided with four possible options. It is important to have an understanding of the anatomy of a sponge to accurately answer this question.

Identifying the Correct Answer

Sponges have tiny pores in their body wall which allow water to enter. These pores are known as Ostia. Thus, the correct answer is (b) Ostia. Osculum is the exit opening in a sponge and Spongocoel is the central cavity of the sponge, but the question is asking for the entry pores.

Key concepts

Sponge Anatomy

Sponges, belonging to the phylum Porifera, possess a simple yet fascinating body structure that is vital for their survival. Their anatomy is designed to support their sessile lifestyle and filter-feeding behavior. A sponge's body is perforated by numerous pores which serve as an entry point for water – these are known as ostia.

As water flows through the ostia, it carries with it oxygen and food particles, which are then absorbed by specialized cells called choanocytes, found along the inner chamber known as spongocoel. The water then exits through a large opening called osculum. This continuous flow of water through the sponge’s body facilitates nutrient uptake, waste removal, and gas exchange, essentially operating as a respiratory and digestive system.

Understanding the anatomy of sponges is crucial for correctly identifying structures such as ostia and osculum. As simple as they may seem, sponges’ ability to efficiently filter water is a hallmark of their evolutionary success, allowing them to thrive in various aquatic environments.

Sponges Water Entry

The water entry in sponges is ingeniously facilitated by its specialized structure – the ostia. These small, innumerable pores scattered across the sponge's body allow water to seep in passively. Due to the architectural arrangement of these pores and the canal system within the sponge, a constant current of water is maintained with the help of flagellated choanocytes.

The pathway of water starts at the ostia, leading to a series of canals and eventually, the central cavity or spongocoel. Here the crucial life processes occur, assisted by the flow of water through the entirety of the sponge. The directed current, despite being gentle, is incredibly effective for the biological needs of these organisms. By understanding this process, students can conceptualize how sponges maintain their vital functions in what seems to be a static lifestyle.

Biology NEET Preparation

For students preparing for the National Eligibility cum Entrance Test (NEET), a thorough understanding of sponge anatomy and physiology is essential, particularly as it's a part of the Zoology syllabus under the Animal Kingdom. One advantageous strategy is to visualize and memorize the flow of water through a sponge, starting from the entry at the ostia to the exit through the osculum.

To reinforce this knowledge, engage in active question-and-answer sessions, utilize diagrams for reference, and apply the concept in various scenarios. Being adept at recognizing sponge structures not only helps in answering direct questions like the textbook exercise but also in solving application-based questions that NEET often presents. The ability to correlate function with structure is a key skill in biology and it's one of the fundamental areas that NEET tests.