How Canal Systems Affect Sponge Size And Body Shape

 

The efficiency of the canal system is the single most important factor determining a sponge's potential size and shape.

• Asconoid: This system has a low surface area of choanocytes relative to its total volume. This makes water flow and feeding inefficient. If an asconoid sponge grew too large, the volume of the central spongocoel would be too great for the flagella to move the water effectively, and most water would pass through without touching a choanocyte. Therefore, they are restricted to very small (a few millimeters) and simple, slender tube shapes.
• Syconoid: The folding of the body wall to create radial canals dramatically increases the surface area available for choanocytes. More choanocytes mean a stronger current and more food capture. This allows syconoid sponges to grow larger than asconoids (up to a few centimeters) and have a thicker-walled, vase-like shape.
• Leuconoid: This system is the most efficient. By replacing one large central cavity with thousands of tiny chambers, it Example: massively increases the choanocyte surface area. This design maximizes the area for food capture and allows the sponge to move a huge volume of water. This evolutionary advantage removes the size limitations of the other systems, allowing leuconoid sponges to achieve very large sizes (meters across) and a wide variety of Good: complex body shapes, such as encrusting, branching, massive, or lumpy forms.