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
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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
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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
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than 1000m
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 1000m
 Abundant in the Antartic
 Upright stature
 Skeleton made entirely of silica
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http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html
http://en.wikipedia.org/wiki/Sponge#Evolutionary_history
http://course1.winona.edu/mdelong/Invertebrate/Porifera.pdf
http://www.buzzle.com/articles/porifera-characteristics.html
http://palaeos.com/metazoa/porifera/porifera.htm
SOURCES