Phylum Mollusca Flashcards
What does the phylum Mollusca mean?
soft
What is the symmetry of the Mollusca?
Bilaterally symmetrical (bilateral asymmetry in some)
Is it segmented?
Unsegmented usually with definite head
What is the ventral body like?
Ventral body wall specialized as a muscular foot, variously modified but used chiefly for locomotion
What is the dorsal body like?
Dorsal body wall forms the mantle, which encloses the mantle cavity is modified into gills or a lung, and secretes the shell (shell absent in some)
Where is the coelom?
Coelom mainly limited to area around the heart
What is the digestive system like?
Complex digestive system; rasping organ (radula) usually present; anus usually emptying into mantle cavity
What is the circulatory system like?
Open circulatory system (most close in cephalopods) of heart (usually three chambered), blood vessels, and sinuses; respiratory pigments in blood
What is the gas exchange like?
Gaseous exchange by gills, lung, mantle, or body surface
What is the highly developed sensory organs in squid? (Cephalopod)
The eyes
What are the four classes?
Gastropoda, Bivalvia, Cephalopoda, and Polyplacophora
What are characteristics and example of the class Gastropoda?
(ex: snails, abalone) Body asymmetrical, head well developed with radula
What are characteristics and example of the class Bivalvia?
(ex: clams & oysters) Body enclosed in a two-lobed mantle, shell of two lateral valves with dorsal hinge; head greatly reduced; no radula
What are example and characteristics of the class Cephalopoda?
(ex: squid) Shell reduced or absent, head well developed with eyes and a radula; head with arms or tentacles
What are example and characteristics of the class Polyplacophora?
(titans) dorsoventrally fattened body with reduced head, radula present; shell of eight dorsal plates
