Characteristics of Phylum Porifera

 

 

1.- Multicellular; body an aggregation of several types of cells differentiated for various functions, some of which                    are organized into incipient tissues of a low level of integration.

 

2.- Body with pores (ostia), canals, and chambers that form a unique system of water currents on which sponges                    depend for food and oxygen.

 

3.- Mostly marine; all aquatic.

 

4.- Radial symmetry or none.

 

5.- Outer surface of flat pinacocytes; most interior surfaces lined with flagellated collar cells (choanocytes) that create        water currents; a gelatinous protein matrix called mesohyl contains amebocytes of various types and skeletal                    elements.

 

6.- Skeletal structure of fibrillar collagen (a protein) and calcareous or siliceous crystalline spicules, often                               combined with variously modified collagen (spongin).

 

7.- No organs or true tissues; digestion intracellular; excretion and respiration by diffusion.

 

8.- Reactions to stimuli apparently local and independent in cellular sponges, but electrical signals in syncytial                      glass sponges; nervous system probably absent.

 

9.- All adults sessile and attached to substratum.

 

10.- Asexual reproduction by buds or gemmules and sexual reproduction by eggs and sperm; free-swimming                            flagellated larvae in most.

 

 

Referense: 

Integrated principles of zoology / Cleveland P. Hickman, Jr. ... [et al.]. – 14th ed. p. cm.