Sponges & Sponge-like Organisms (Chapter 11)

Question 1

Porifera

Answer 1

• phylum level name for sponges
• sporadic fossil record
• unique porous structure
• body plan based at cellular level of organization (without tissues or organs)
• calcareous, organic or siliceous spicules

Question 2

Porifera Body Plan

Answer 2

• Parazoan body plan
• 3 cells types: epithelial, collar cells (choanocytes), amoeboid cells (digestive, reproductive, skeletal functions)
• no tissues or organs
• cells may switch functions (feeding cells → sexual reproduction)
• sexual or asexual (budding)
• skeleton: spongin (horny organic material; spicules (of silica or calcium carbonate)

Question 3

ascon

Answer 3

sponges which are sacs with single chamber lined by flagellate cells

Question 4

sycon

Answer 4

sponges with #’s of simple chambers with single central paragaster

Question 5

leucon

Answer 5

• sponges with series of sycon chambers accessing a large central paragaster
• most common body plan in sponges

Question 6

Calcarea

Answer 6

• sponges with calcitic spicules
• single and/or porous calcareous walls
• typically found in marine environments
• Cambrian to Recent

Question 7

Desmospongia

Answer 7

• sponges with skeletons of spongin, mix of spongin & siliceous spicules, or only siliceous spicules
• marine, brackish, & fresh water environment
• Cambrian to Recent

Question 8

Hexactinellida

Answer 8

• glass sponges with complex siliceous spicules
  
  • 6 rays directed along 3 mutually perpendicular axes
• deeper-water marine
• Cambrian to Recent (possibly Pre-Cambrian)

Question 9

Stromatoporoidea

Answer 9

• sponge-like, modular organisms
• skeleton - undulating layers of calcareous laminae punctuated perpendicularly by vertical pillars → superficially resemble tabulate corals
• marine
• appeared in Mid-Ordocivian

Question 10

Archaeocyatha

Answer 10

• group of calcareous skeleton of porous cup or cone-like structured animals
• strictly marine
• first reef builders
• index fossil for Cambrian