Reading Check Sponges

Reading Questions, p. 262 - 270 What is the name of the phylum for sponges? What type of symmetry is displayed by sponges? Name one body plan of the sponges.

Today’s Objectives The student will list the characteristics, classification, economic importance, reproductive strategies and organizaiton of members of Phylum Porifera.

Characteristics of Poriferans Assymmetrical or radially symmetrical Nonmotile No tissues or organs Filter feeders Three types of cells

Classification – Phylum Porifera Based on type of spicules Class Calcarea – CaCO3 Class Hexactinellida – SiO4 Class Demospongiae – spongin or SiO4 or both

Class Calcarea

Class Hexactinellida

Class Demospongiae

Cell types of sponges Pinacocytes Porocytes Mesohyl (amoeboid cells) Choanocytes Spicules of calcium carbonate or silica Spongin skeleton

Body Types of Sponges Ascon Sycon Leucon

Reproduction Monoecious Do not self-fertilize Amoeboid cells or choanocytes undergo meiosis to form sperm or egg cells Sexual reproduction – forms larvae Asexual reproduction – forms gemmules

Economic Importance Commercial production of sponges Artificial vs. Natural