Porifera

Question 1

Asymmetry

Answer 1

Asymmetry: Body lacks definitive shape or structure that can be divided into equal halves

Question 2

Calcarea

Answer 2

Calcarea: Class of Porifera that have calcium carbonate spicules

Typically small and can have asconoid, syconoid, or leuconoid body forms

Question 3

Hexactinellida (Glass Sponges)

Answer 3

Hexactinellida (Glass Sponges): silica-based spicules

Often found in deep sea environments and typically exhibit leuconoid or syconoid structure

Question 4

Demospongiae

Answer 4

Demospongiae: Largest class of Porifera, containing around 90% of all sponge species

Skeletons made of spongin and/or siliceous spicules

Most have a leuconoid body form

Question 5

Asconoid

Answer 5

Asconoid: Simplest sponge body form w/ tubular shape and single central cavity (spongocoel)

Water flows directly into spongocoel through pores and exits through large opening (osculum)

Question 6

Syconoid

Answer 6

Syconoid: More complex sponge structure than asconoid

Walls fold to form canals, increasing SA for filter feeding

Water flows through incurrent canals, passes through radial canals lined with choanocytes, and then into spongocoel

Question 7

Leuconoid

Answer 7

Leuconoid: Most complex sponge body type, featuring highly branched canal system

Water flows through network of incurrent canals, passes through choanocyte chambers, and exits via excurrent canals

Leuconoid sponges lack large central cavity

Question 8

Mesohyl

Answer 8

Mesohyl: Gelatinous, non-cellular matrix located between outer layer (pinacoderm) and inner layer (choanoderm)

Contains cells and spicules that contribute to sponge’s structure

Question 9

Choanocyte

Answer 9

Choanocyte (Collar Cell): flagellated cells w/ collar of microvilli that line internal chambers of sponges

Help in water movement and filter feeding