4 - Porifera Flashcards
What are the two words that form Porifera?
pore + ferre (to bear)
What are the classes under porifera?
Calcarea
Hexactinellida
Demospongiae
- marine
- skeleton has calcareous spicules
- spicules are either needle-shaped or 3-/4- rayed
- all canal systems are represented
- spicules are not differentiated
Calcarea
- marine
- usually deep-sea glass sponges
- skeleton has 6-rayed siliceous spicules extending at right angles from a central point and united to form a network
- body often cylindrical/funnel-shaped
- syconoid/leuconoid arrangement
- has megascleres and microscleres
Hexactinellida
- Marine/freshwater
- skeleton has either siliceous spicules, sponging fibers, or both
- megasceres monaxon/tetraxon (NEVER 6-rayed)
- microscleres of diverse type
- leuconoid canal system
Demospongiae
Tiny pores for incoming water
Ostia
tiny openings for Water outlet
Oscula
How are the ostia and oscula connected
System of canals lined with specialized cells to perform various, independent functions
Covers the exterior surface of sponge
Dermal pinacoderm
Composition of dermal pinacoderm
Pinacocytes (thin layer of flat cells)
Incurrent pores
Ostia
- where the ostia lead to
- They end blindly near the inner surface of the body wall
- Connected to radial canals
Incurrent canals
- composition of incurrent canals
- Single layer of collared, flagellated cells
Choanocytes
Large central canal that radial canals lead into
Spongocoel
Minute pores that lead into the spongocoel
Apopyles
Matrix between pinacoderm and choanoderm
Mesohyl
- roaming cells that carry many functions (inc. distributing food to other cells, reproduction, production of sponge’s skeleton)
- Composition of matrix
Amoebocytes
- Provide support & prevent collapse of hollow bodies, esp at great depths
- Wide variety of forms, size, and degree or ornamentation
Spicules
Two kinds of compositions of skeletal support of sponges
Calcareous
Siliceous
- Insoluble, sulphur-containing form of collagen
- Usually occurs as interwoven fibers
Spongin
Which class usually has spongin?
Demospongiae
How do freshwater sponges and some marine forms perform asexual reproduction
Through the formation of gemmules
- A hollow cyst-like ball of archeocytes/amoebocytes
- Covered with a tough coat of sponging with numerous siliceous spicules embedded to it.
Gemmules
