Chapter 9 Lect Flashcards
(28 cards)
- Asymmetrical or superficially radially symmetrical.
- Three cell types: pinacocytes, mesenchyme cells, and
choanocytes. - Central cavity, or a series of branching chambers, through
which water circulates during filter feeding. - No tissues or organs.
Phylum Porifera
epidermal cells; outer cells
Pinacocytes
jelly like layer bet pinacocytes and choanocyte; middle cellsj
Mesenchyme
flagellated cells responsible for filtering water and food;
inner cells
Choanocytes
central space where water circulates during filter feeding
Spongocoel
The animal phylum whose members are sessile filter feeders and either asymmetrical or radially
symmetrical; body organized around a system of water canals and chambers; skeletal elements may be
(spicules) composed of calcium carbonate or silicon dioxide (silica); spongin present in some; tissuegrade organization. Approximately 9,000 species.
Phylum Porifera
Spicules composed of calcium carbonate; spicules are needle shaped or have three or four rays;
ascon, leucon, or sycon body forms; all marine. Calcareous sponges. Grantia (=Scypha), Leucosolenia.
Class Calcarea
Spicules composed of silica and six rayed; spicules often fused into an intricate lattice; cup or vase
shaped; syncytial epithelia; sycon or leucon body form; often found at 450 to 900 m depths in tropical
West Indies and eastern Pacific. Glass sponges. Euplectella (Venus flower-basket).
Class Hexactinellida
Brilliantly colored sponges with needle-shaped or four-rayed siliceous spicules or spongin or both;
leucon body form; up to 1 m in height and diameter. Includes one family of freshwater sponges,
Spongillidae, and the bath sponges. Cliona, Spongilla.
Class Demospongiae
Anatomically simple and encrusting in form.
Siliceous spicules small and simple in shape or absent. Occur at depths ranging from shallow marine
shelves to depths of 1,000 m. Oscarella, Plakina.
Class Homoscleromorpha
outer body wall of poriferans; outer epidermis
* Made up of connected cells pinacocytes;
Pinacoderm
underneath the pinacoderm;
* Supportive material of all poriferans
Mesohyl
amoeboid stem cells found in the mesohyl;
differentiate into virtually any other cell type
* Responsible for the distribution of the filtered food throughout the
poriferan body
Archeocytes
contractile cells used for movements.
Myocytes
inner epithelial layer; interior surface of the mesohyl
Choanoderm
collar ring of flagellated cells that create pressure to draw water in and filter its contents.
choanocytes
small openings in the body wall for the entry of
water
Dermal pores or ostia
water moves out of this structure after being filtered; little mouth
Oscula
framework of the poriferans; microscopic needles formed by
ameboid cells
* Made up of calcium carbonate or silica with variety of shapes.
Spicule
vaselike; dermal pores lead directly to the space called
spongocoel
* Movement of water: Dermal pores -> choanocytes -> spongocoel ->
osculum
* Choanocytes draw the water and lined the spongocoel
Ascon
walls are folded
* Water enters through the dermal pores called incurrent canals –
invaginations of the body wall
Movement of water: Dermal pores -> incurrent canals -> radial canals ->
choanocytes -> spongocoel -> osculum
Sycon
extensively branched system
* Movement of water: Dermal pores -> branched incurrent canals ->
choanocytes -> excurrent canals -> oscula
* Absence of spongocoel and replaced by excurrent canals
Leucon
- Bacteria, algae, protists, suspended organic matter.
- Trapped in choanocyte collar and incorporated into food vacuole.
- Digestion by lysosomal enzymes and pH changes.
Nitrogeneous waste removal and gas exchange.
Filter feeding.
Suspended food is trapped on the collar and moved to the collar to be
processed by a
food vacuole.
