Practice question

Sponge aquiferous system illustrates increasing complexity and filtration efficiency from simplest asconoid with thin wall single central spongocoel entirely lined by choanocytes to syconoid where wall folded into radial canals increasing choanocyte surface to most derived leuconoid where choanocytes restricted to numerous small spherical chambers interconnected by network of incurrent canals bringing water from ostia and excurrent canals draining to osculum through thick mesohyl. Leuconoid maximizes choanocyte surface to volume ratio enables larger body size generates powerful unidirectional flow enhancing filtering capacity. Present in majority Demospongiae Hexactinellida and most freshwater sponges representing pinnacle poriferan filter-feeding adaptation for benthic ecosystems.