Sponges - Porifera

Phylum Porifera - sponges --- “pore bearing” Kingdom Animalia -Metazoans Branch Parazoa - ‘near life’ symmetry - radial or none no real tissues, organs or organ systems they lack--- digestive, excretory, respiratory circulatory, nervous (?), muscular systems, and no appendages respiration by diffusion ---> surface to volume ratio

4 2 4 2 4 2 S.A. = (2 x 2) x 6 = 24 sq in (4 x 4) x 6 = 96 sq in V = 2 x 2 x 2 = 8 cu in 4 x 4 x 4 = 64 cu in S:V = 24 / 8 = 3 96 / 64 = 1.5

Anatomy of an Asconid Sponge Respiration Digestion Excretion

Other types of sponges have a more complex body walls, with foldings and convolutions

Syconid sponges have simple folding of the body-wall these folds form the walls of the incurrent canals ~choanocytes are only in the radial canals (the internal folds) and do not line the spongocoel Leuconoid sponges have the most complex body type many chambers with choanocytes lining a flagellated chamber

Structural support Spicules ~calcareous CaCO2 ~siliceous SiO2 Secreted by sclerocytes

Spongin - a soft, proteinaceous, fibrous material for support

Reproduction - asexual regeneration re-aggregation and de-differentation budding

Reproduction- sexual Dioecious - separate sexes Monoecious - an individual has both male and female reproductive components

Choanocyte epidermis Stomatoblastula amphiblastula