Invertebrates: Phylum Mollusca General (EXAM 2)

Question 1

Phylum Mollusca

Answer 1

ex) snails, slugs, nudibranchs, clams, mussels, oysters, squid, octopus, nautilus, cuttlefish

Question 2

Worldwide distribution

Answer 2

100,000 species (70,000 fossil)
range in size from micromolluskan snails and crabs to giant squid (60-80 ft)
are mostly marine but some are freshwater and terrestrial

Question 3

Bilateral Symmetry

Answer 3

body design arranged along a left and right axis (two halves)

Question 4

Foot

Answer 4

muscular appendage used for locomotion

Question 5

Mantle

Answer 5

folds of skin that act as a protective covering; secretes the shell in some forms: conchiolin and perlucin and chitin secreted by the mantle; outer shell layer or periostracum also composed of conchiolin

Question 6

Conchiolin and Perlucin

Answer 6

complex proteins secreted by the mantle

Question 7

Chitin

Answer 7

polysaccharide secreted by the mantle

Question 8

Periostracum

Answer 8

composed of conchiolin, is the outer shell layer

Question 9

Radula

Answer 9

rasping, protrusible tongue-like structure for feeding (except bivalves)

Question 10

Coelom

Answer 10

body cavity that contains well developed internal organ systems

Question 11

gills or lungs

Answer 11

either freshwater or terrestrial forms

used for respiration

Question 12

open circulatory system

Answer 12

3-chambered heart, hemolymph fills the body cavity and bathes (surrounds) internal organs (muscular movement during locomotion facilitates hemolymph circulation), When the heart relaxes, the hemolymph moves back to the heart through a system of open pores, not used for oxygen transport: nutrients

Question 13

Metanephridia

Answer 13

kidneys (nephrocytes absorb toxins or convert them into a form suitable for elimination)

Question 14

hemolymph

Answer 14

blood

circulation is facilitated by muscular movement during locomotion

Question 15

paired ganglia

Answer 15

nervous system and sensory organs- touch, smell, taste, equilibrium, vision (Highly developed in cephalopods)

Question 16

Reproduction

Answer 16

most are sexual (male/female) some are hermaphroditic (individual with both male/female structures)

Question 17

seafood allergy

Answer 17

millions of people have hypersensitivity or allergic reactions to dietary substances from shellfish or crustaceans, which causes the immune system to overreact, producing severe physical symptoms and sometimes death