OCSC 2000 - Phyla Porifera (Sponges)

Up to 2ft tall

Height of porifera

Sessile suspension feeders

What type of feeder are Porifera?

Skeletal structure, no true tissues

Skeletal/muscular system of Porifera

Asymmetrical or superficially radially symmetrical

Symmetry of Porifera

Totipotent cells

Type of cells in sponges that can differentiate into any type of cell in a sponge; similar to human stem cells.

Aquiferous System

Network of canals/chambers that circulate water throughout a sponge; assists in feeding, respiration and excretion

Calcarea (calcareous sponges), Hexachinellida (glass sponges) & Demospongiae (demosponges)

Three classes of Porifera

Calcarea

Type of sponge with spiculues skeletal structure made from entirely calcium carbonate

Live in shallow waters; pale and small in size

Hexactinellida (glass sponges)

Sponge with a skeleton made of silica spicules that fuse together to form a “glass house”

Live in deep water and extend their long spicules into the sediment to anchor themselves

Demospongiae

Most diverse group of sponges (~85% of sp)

Soft body w/ hard skeleton made of calcium carbonate, aragonate or calcite

Pinacoderm

Outermost layer of cells in sponges; no basal membrane and Ostia present

Pinacodytes

Thin flat cells that form the outer layer of sponge (pinacoderm); protection, structure, and water flow

Endopinacodytes

Line internal canals of sponge (water flow & nutrient absorption)

Basalpincodytes

Form basal layer; help with anchorage

Choanoderm

Inner layer of a sponge; composed of flagellated choanocytes

Chanocytes

Flagellated cells that make up choanoderm; Capture food particles, creat currents, phagocytosis (food particles)

Mesohyl

Middle tissue layer in sponges; not “true” mesoderm - non-cellular/gelatinous. Thickness varies

Totipotent cells

Type of cells present in mesohyl; can differentiate into any/all cells of an organism

Digestion, Gamete production, Secretion of skeleton, Transport of nutrients/waste

What are the roles of mesohyl?

Archaeocytes

The type of totipotent cells in Porifera; very motile & located in mesohyl

Asconoid

Sponge with a simple body plan; tube shaped with a single opening (osculum)

Ostia

Pores in the external surface of porifera → crucial for gas exchange/circulation as well as feeding processes

Spongocoel

Central cavity of Porifera; gastrovasucular cavity

Aquiferous system

System of channels and canals that water flows through in Porifera; respiration, digestion, excretion

Fragmentation (asexual)

Organism breaks into pieces to form new organisms; genetically identical to parent

Gemmules

Made from amoebacytes surrounded by spicules; internal budding

Reproduction Bodies

Ball-shaped structures that form when freshwater/estuarine sponges disintegrate