Lab 9 - Mollusca Flashcards
Are mollusca lophotrochozoans or ecdysoans?
Lophotrochozoans
What are the four classes of mollusca?
polyplacophora, gastropoda, cephalopoda, bivalvia
What organisms are found in the class polyplacophora?
Chitons
What organisms are found in the class gastropoda?
snails and slugs
What is torsion and what class can do it?
the body folds 90 to 180 degrees - gastropoda do this
What organisms are in the class bivalvia?
clams and relatives :)
What organisms are in the class cephalopoda?
squids, octopuses, cuttlefish, and nautilus
What kind of symmetry do mollusca have?
bilateral
Are mollusca deuterostomes or protostomes?
protostomes
Do mollusca shed a cuticle to grow?
hell no
What level of organization are mollusca?
organ-system
What kind of body cavity do mollusca have?
coleom
How many germ layers do mollusca have?
3 - triploblastic
What are the distinctive features of mollusca?
mantle, mantle cavity, visceral mass, and foot
What is a mantle?
epidermal sheet of skin that secretes the shell
What is a mantle cavity?
fold in the mantle that houses gills, opening anus
What is the visceral mass?
enclosed by the mantle, where most vital organs are located
What is a foot? (not the human foot, the mollusca foot)
muscular tissue used for movement; can be drawn into the shell
What kind of digest system do mollusca have?
complete (mouth and anus)
What are radula in mollusca?
tongue-like organ that is for feeding (scrapes)
Where are radula not found?
bivalvia
What kind of circulation do mollusca have?
open in most
closed in cephalopods
How do aquatic mollusca respire?
gills
How do terrestrial mollusca respire?
vascularized mantle wall
How do mollusca excrete?
Pair of metanephridia - connected to coelom
What kind of sensory systems do mollusca have?
varying degrees of cephalization, several pairs of ganglia with connecting nerve chords, complex brain/eyes
What kind of support system do mollusca have?
external shell (bivalves, most gastropods); internal shell (cuttlefishes); internal shells known as pens (squids); no shells (octopuses
Mollusca - locomotion (how do they do it?)
most move with their muscular foot; cephalopods have a mantle modified for water jet propulsion - siphon
How do mollusca reproduce?
external fertilization for some, most are internal; monoecious or dioecious (majority)
What is the difference between open and closed circulatory systems?
open: fluid leaves vessels (arteries)
closed: fluid stays in vessels (arteries)
What is a benefit of having a closed circulation system?
mollusca with a closed system can move faster and grow larger
