Phylum mollusca ch 16 pt 2

Question 1

Layers of the shell in phylum Mollusca
and what secretes the shell?

Answer 1

mantle secretes the shell
– Inner layer = nacreous layer
– Middle Layer = prismatic layer
– Outer layer = periostracum

Question 2

what has torsion?

Answer 2

class Gastropoda

Question 3

what kind of torsion does class gastropodia have?

Answer 3

Ontogenetic Torsion

Question 4

what is Ontogenetic Torsion in class gastropodia

Answer 4

During development, anus and mantle cavity twist to the right
anus & mantle cavity end up over the head

Avoid fouling:
- H2O in L side; out R side
- Openings in shell
- Bilateral asymmetry

Question 5

What are parts of the gastropod shell? in class gastropodia

Answer 5

• Univalve (one piece)
• Apex is oldest whorl
  
  • tip of shell
• Coiling genetically controlled
  – Right coil = dextral
  – Left coil = sinistral
• Most with Operculum to cover aperture

Question 6

cuttlefish

Answer 6

change color to attract mates
- can change color on one side and not the other

Question 7

Chambered Nautilus

Answer 7

round spiral shell thing
- have tentiles w/ out suction
- has multiple gas-filled chambers but lives in last one