Question

Water path in sponges is (a) Ostia \(\rightarrow\) Spongocoel \(\rightarrow\) Osculum (b) Osculum \(\rightarrow\) Spongocoel \(\rightarrow\) Osculum (c) Ostia \(\rightarrow\) Spongocoel \(\rightarrow\) Ostia (d) Spongocoel \(\rightarrow\) Ostia \(\rightarrow\) Osculum

Short answer

The correct answer is Option (a): Ostia \(\rightarrow\) Spongocoel \(\rightarrow\) Osculum.

Step-by-step solution

Identify correct sequence

Begin by looking at the series presented in each choice. Four options are given and only one of them represents the accurate sequence. The water in a sponge should flow from the Ostia, through the Spongocoel, and then out the Osculum.

Match with correct sequence

Now match each sequence with the above-mentioned sequence. Only the option (a) Ostia \(\rightarrow\) Spongocoel \(\rightarrow\) Osculum matches the correct flow of water in a sponge.

Confirm Answer

With the matching option found in the second step, the correct answer is then confirmed as Option (a): Ostia \(\rightarrow\) Spongocoel \(\rightarrow\) Osculum.

Key concepts

Ostia

Have you ever wondered how sponges, simple yet fascinating creatures, draw water into their bodies? They use tiny pores called ostia. Think of ostia as miniature gateways speckling the surface of the sponge's body. They are essentially entry points that allow water to penetrate into the sponge.

Picture the surface of a sponge, and imagine water carrying food particles and oxygen being sucked through these gates into an internal maze of canals. The ostia play a vital role in the respiration, feeding, and excretion processes of a sponge's biology. Due to their small size, ostia also act as a filter, preventing large particles that could harm the sponge from entering its delicate internal structure.

Spongocoel

Once through the ostia, water embarks on a journey through the central cavity of the sponge known as the spongocoel. This spacious chamber forms the core of the sponge's body. The spongocoel isn't just an empty space; it's lined with special cells called choanocytes or collar cells.

These cells are equipped with tiny whip-like structures called flagella that beat back and forth, creating a current which draws water through the sponge. The spongocoel acts as the main conduit for water traveling through the sponge's body, allowing the sponge to filter food particles and absorb dissolved oxygen before the water exits through another structure called the osculum.

Osculum

Our journey through the sponge leads us finally to the osculum, the grand exit point for water that has traveled through the sponge. The osculum is typically larger than the ostia and is positioned on the top side of sponge, acting as a kind of chimney through which the filtered water is expelled.

As the flagella of the choanocytes propel the water out, waste and debris are flushed away from the sponge. It is this continuous flow of water from ostia to spongocoel to osculum that constitutes the sponge's simple, yet efficient, canal system.

Porifera Circulation

The entire process of water moving through the sponge's body is known as porifera circulation and is critical for the creature's survival. Without any circulatory organs like hearts or veins, sponges rely on this water movement, driven by the flagella of choanocytes, to circulate nutrients and oxygen throughout their bodies.

The system is so effective that sponges can filter several times their own volume of water every day. This circulation not only nourishes the sponge but also helps to draw in sperm during sexual reproduction, proving that even the simplest of creatures have sophisticated means of surviving and reproducing in their aquatic environments.