meaning pore bearer GROUP 36 JESSICA PENNEY TONIKA

meaning "pore bearer" GROUP 36: JESSICA PENNEY, TONIKA LEVY, AND KRISTEN YOUNG

Evolutionary History �Previously assigned to a separate subkingdom, Parazoa �Closest single-celled relatives are thought to be choanoflagellates �Does not form a monophyletic group �Fossil records of sponges have been found from about 580 million years ago �Archaeocyathids were a type of coralline sponge �~5000 known species; ~150 freshwater species

Basic Characteristics �Cellular-level organization �Body support (“skeleton”) provided by spicules �Filter feeders through pores �Either radially symmetrical or asymmetrical �Spicules and potential biotoxin for defence �Adults are sessile; larvae are motile �Reproduction: �Hermaphrodites �Sexual ; Asexual

Structure �Body is divided into three layers: �The outermost layer comprised of pinacocytes �The middle layer, mesohyl �The innermost layer, choanocytes § § ASCONOID SYNCONOID LEUCONOID Pinacocytes (Epidermal cells) Choanocytes (Collar cells) Mesohyl (Semi-fluid matrix) Water flow

Classification �Phylum Porifera �Class Calcarea �Class Demospongiae �Class Hexactinellida

Class Calcarea �About 400 described species in this group �Exclusively marine; shallower, sheltered waters less than 1000 m �Tropical regions associated with the coral reefs �Members of this group have large structural spicules �Skeletons made of calcite �Mainly dull, some colorful

Class Demospongiae �Contain the largest number of species with 4750 species organized into 10 orders �Marine environment; intertidal to the abyssal zone; some species inhabit freshwater �Silicate spicules or spongin fibers or both within their soft tissues �Brightly colored

Class Hexactinellida �Glass sponges �Depths between 200 and 1000 m �Abundant in the Antartic �Upright stature �Skeleton made entirely of silica

• • • http: //animaldiversity. ummz. umich. edu/site/accounts/information/Porifera. html http: //en. wikipedia. org/wiki/Sponge#Evolutionary_history http: //course 1. winona. edu/mdelong/Invertebrate/Porifera. pdf http: //www. buzzle. com/articles/porifera-characteristics. html http: //palaeos. com/metazoa/porifera. htm SOURCES