Phylum Porifera

Question 1

Major Taxa and distinguishing characteristics (7)

Answer 1

Grantia – Triactine calcium spicules with syconoid form
Scypha – calcarae sponge showing syconoid form
Cliona – responsible for the shell erosion of bivalves (demosponge)
Aphrocallistes – local hexactinellid
Ephydotia – freshwater sponge that produces gemmules (demosponge)
Halichondria – local species that emits bad odour when crushed (demosponge)
Occidentalis – shallow water predatory sponge BC coast (demosponge)

Question 2

3 Types of structures

Answer 2

Asconoid: single atrium and oscula
Syconoid: Multiple radial canals and single oscula
Leuconoid: Many internal flagellated choanocyte chambers and multiple oscula

Question 3

Canal system, tissue layers and cell types syconoid sponge

Answer 3

Incurrent canals, radial chambers, spongocoel, mesohyl, pinacoderm, choanoderm

Question 4

Sexual and Asexual Reproduction in Sponges

Answer 4

Hermaphroditic, but not at the same time. Broadcast spawning sperm and taking into the mesohyl
Flagellated larva swim out of the osculum

Question 5

Recognize gemmules and their functional significance

Answer 5

Gemmules are an overwintering structure that freshwater sponges produce in adverse conditions
Its asexually produces a mass of cells that develops into a new organism when conditions improve

Question 6

Recognize spicule shape and their functional role and composition

Answer 6

Spicules provide a skeletal structure internally, that can be monoaxon or triaxon
They can be made of silica or calcium carbonate
Demosponges are generally monoaxon, calcarae are generally triaxon and hexactinellida are hexactine
Calcarae are made of calcium carbonate, and silica belongs to demosponges and hexactinellid