meaning "pore bearer"
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Porifera /prfr/; meaning "pore bearer"
meaning "pore bearer"Group 36: Jessica Penney, Tonika Levy, And Kristen YoungPoriferaSponge
Evolutionary HistoryPreviously assigned to a separate subkingdom, ParazoaClosest single-celled relatives are thought to be choanoflagellatesDoes not form a monophyletic groupFossil records of sponges have been found from about 580 million years agoArchaeocyathids were a type of coralline sponge~5000 known species; ~150 freshwater species
2Basic CharacteristicsCellular-level organizationBody support (skeleton) provided by spicules Filter feeders through pores Either radially symmetrical or asymmetricalSpicules and potential biotoxin for defenceAdults are sessile; larvae are motile Reproduction:HermaphroditesSexual ; Asexual
3StructureBody is divided into three layers:The outermost layer comprised of pinacocytesThe middle layer, mesohylThe innermost layer, choanocytes
Pinacocytes (Epidermal cells)Choanocytes (Collar cells)Mesohyl (Semi-fluid matrix)Water flowAsconoid Synconoid Leuconoid
4ClassificationPhylum Porifera Class CalcareaClass DemospongiaeClass Hexactinellida
5Class CalcareaAbout 400 described species in this groupExclusively marine; shallower, sheltered waters less than 1000mTropical regions associated with the coral reefsMembers of this group have large structural spiculesSkeletons made of calciteMainly dull, some colorful
6Class DemospongiaeContain the largest number of species with 4750 species organized into 10 ordersMarine environment; intertidal to the abyssal zone; some species inhabit freshwaterSilicate spicules or spongin fibers or both within their soft tissuesBrightly colored
7Class HexactinellidaGlass spongesDepths between 200 and 1000mAbundant in the AntarticUpright stature Skeleton made entirely of silica