lab/lecture 9: molusca gastropoda Flashcards
(15 cards)
What’s the basic body plan of Phylum Mollusca?
Foot, mantle, shell; coelomate protostomes with reduced coelom, hemocoel, head-foot-visceral mass, radula, complete gut, mantle cavity with gills (ctenidia).
What happens during torsion in gastropods?
The visceral mass rotates 180°, creating a U-shaped gut.
Describe (class) Gastropoda fossils.
Coiled (trochospiral) or uncoiled shells, apex, body whorl, umbilicus, aperture, sometimes with operculum or siphonal canal.
Describe (Class) Polyplacophora (chitons)
Chitons have 8 calcareous, overlapping shell plates; a broad, flattened foot; repeated pairs of gills; and a radula for scraping algae.
Describe (Class) Scaphopoda (tusk shells).
Scaphopods are burrowing marine molluscs with tubular, tusk-shaped shells open at both ends; they have a reduced head and use captacula to collect food.
Describe (Subclass) Prosobranchia.
Marine gastropods with shells and gills; include herbivores and predators; examples are limpets, whelks, and cone shells.
Describe (Order) Archaeogastropoda.
Primitive, herbivorous gastropods with low-spired shells and double gills; common from Cambrian to Recent.
Describe (Order) Mesogastropoda.
Gastropods with various shell shapes and complex gills; found from the Ordovician to Recent; they have diverse ecologies
Describe (Order) Neogastropoda.
High-spired, mostly carnivorous gastropods with siphonal canals; some have venomous radular teeth; Cretaceous to Recent.
Describe (Subclass) Opisthobranchia.
Marine gastropods like sea slugs that have reduced or lost shells, undergone detorsion, and often display bright warning colors; some are toxic.
Describe (Subclass) Pulmonata.
Terrestrial and freshwater gastropods with lungs (modified mantle cavity); includes most land snails and slugs; shell often reduced or lost
Describe (Family) Fissurellidae.
Limpet-like shells with a hole or slit for exhalant water flow and waste removal; water passes over gills and exits through the opening
Describe a gastropod shell’s key parts.
Cone-shaped, coiled in a spiral (trochospiral); includes apex, spire, whorls, suture, body whorl, umbilicus, peristome, and often an operculum; some have siphonal canals, ribs, or spines
Describe a typical radula.
A ribbon of tiny mineralized teeth on a chitinous band used for scraping, boring, or predatory feeding; teeth are constantly replaced.
Describe the ecological range of gastropods.
Gastropods fill roles from algal scrapers and plant grazers to scavengers and predators; they inhabit marine, freshwater, and terrestrial environments.
