Unit 5 - Sponges and Placozoans

Porifera, Cnidaria, Placozoa, Ctenophora

Phylum

Porifera

Marine

Adult sponges are sessile and larvae are free swimming

Sponges filter water into their ostium, the water goes into the spongocoel and out the oscullum.

Asymmetrical, Radial symmetry, Spicules, Spongin.

Archaeocytes, Choanocytes, Pinacocytes, Porocytes.

Flat cells that make up the outer and sometimes inner layers of the sponge (pinacoderm). Regulate contractions of entrance.

Cells that move throughout the mesohyl of the sponge and transport/digest nutrients that are caught by the choanocytes.

Form the ostia of some types of sponges.

Flagellated, collared cells lining canals. Create and maintain current, trap and engulf passing by substance.

Hermaphrodites, choanocytes and archaeocytes.

Most sponges release sperm into the water which is trapped by another sponges choanocyte and carried to the egg in their mesohyl.

budding and gemmules

Archaeocytes encased in spongin and spicule coat to survive harsh weather.

The asconoid takes in water through the ostia into the choanocyte lined spongocoel and then out the osculum.

Syconoid takes in the water through the Ostia, into the incurrent canal, then the prosopyle into the radial canal which goes out the apopyle and into the spongocoel lined with choanocyte.

Ostia leads to the incurrent canals and then the flagellated chambers then the excurrent canals, oscullum.

Calcarea, Hexactinellida, Demospongiae, Homoscleromorpha.

Has all 3 canal systems with calcium carbonate spicules with 0, 3, 4 rays.

Leuconoid canal system, 95% of living sponges. Silicon dioxide spicules without 6 rays.

Leuconoid canal system. Silicious spicules lack the central filament.

Either syconoid or leuconoid canal system. Silicon dioxide spicules with 6 rays. Body cells all joined as one.