Chapter 33 Phylums
Subject:
Biology [1]
Phylum Porifera Characteristics The simplest of all animals with no formal digestive, circulatory, or nervous systems. They display radial symmetry and assymmetry. They have two layers: an endoderm and an ectoderm. Most are salt water sponges. Classification The four classes are grouped according to skeletal structure. Protection Some members are poisonous or they taste bad. Movement Adults are sessile (they don't move) while larvae are free swimming. Feeding & Digestion Porifera are filter feeders (they filter food out of the water). They have intracellular digestion. Circulation Circulation in porifera is mainly carried out through diffusion. Reproduction