invertebrate phylum mollusca (mollusks)
DESCRIPTION
Invertebrate Phylum Mollusca (Mollusks). Vocabulary visceral mass =contains internal organs of digestion, excretion, and reproduction mantle = thin membrane that surrounds internal organs. Vocabulary Radula = tongue-like structure with teeth used to grate, cut, and scrape - PowerPoint PPT PresentationTRANSCRIPT
Invertebrate Phylum
Mollusca
(Mollusks)
Vocabularyvisceral mass = contains internal
organs of digestion, excretion, and reproduction
mantle = thin membrane that surrounds internal organs
VocabularyRadula = tongue-like structure
with teeth used to grate, cut, and scrape
Torsion =visceral mass twists 180* in relation to head
Siphon = fleshy tubes for movement of water in a mollusk
Characteristicstrue coelm
* bilateral symmetry* two body openings
* 3 body parts: head, muscular foot, visceral mass
* most have shell secreted by mantle* gills for gas exchange with water* some have a radula for feeding
Gastropoda: "stomach foot"
* single shell - snails, abalone, conch* no shell - nudibrachs, slugs* move by muscular contractions of
foot* open circulatory system
Bivalvia: shell with "two valves”* clams, oysters, scallops
* strong muscle for pulling shell and burrowing
* no head or radula* filter food from water via gills; cilia
move food to stomach
Cephalopoda: "head-foot”
* octopuses, squid, nautilus* free swimming; predatory; tentacles
with suckers* radula and sharp beak* large brain and advanced nervous
system* closed circulatory system