Mollusca Part I & II Flashcards
What is the second largest animal phylum, mostly marine with ~90000 described species, are soft bodied and eucoelomate?
Mollusk
What group of mollusk have adapted for land?
Snails and slugs
In mollusk, what is it called when the coelom is restricted to a cavity around the heart in adults?
Eucoelomate
True or False:
Majority of mollusks are small, largest can grow 20m or up to 900 kg
True
In mollusk, what general body plan contains the feeding, sensory, and locomotor organs?
Head-foot
In the head-foot, what contains the mouth and specialized senosry structures such as photoreceptors?
Head
In the head-foot, what are extendable tongue-like organ found in all mollusks except bivalves and most solenogaster, has filelike teeht made of chiting for scraping, piercing, tearing, or cutting?
Radula
In the head-foot, what supports the radula?
Odontophore
In the head-foot, what is adapted for movement or attachment to surfaces, usually located on the ventral surface and movement is typically waves of muscle contraction and modified in some groups?
Foot
In mollusk, what general body plan contains digestive circulatory, respiratory, and reproductive organs and found above the foot?
Visceral mass
In the visceral mass, what is the tissue that extends outward from the visceral mass, secretes the shell, contains sensory receptors, capelike; wraps around the body?
Mantle
In the visceral mass, what is the space between the visceral mass and mantle, houses respiratory organs such as gills and lungs and the digestive, reproductive and excretory system products are emptied here?
Mantle cavity
True or False:
The respiratory organs develop from the mantle
True
What mollusks have water continuously pumped into the mantle cavity for respiration, feeding, and excreon?
acquatic mollusks
What mollusks use the mantle and mantle cavity for jet propulsion?
Cephalopods
In the visceral mass, what is secreted by the mantle, has 3 layers, are varied, and gets calcium from the environment?
Shell
In the shell, what are the 3 layers?
- Periostracum
- Prismatic layer
- Nacreous layer
in the shell layers, What are the prismatic and nacreous layers made of?
Calcium carbonate
In the shell layers, what is the periostracum made of?
Conchiolin
What mollusk has a thin periostracum or sometimes absent?
Marine mollusks
In the visceral mass, what are generally less efficient at supplying oxygen and found in MOST mollusks?
Open circulatory systems
In visceral mass, what do cephalopods have?
CLosed circulatory system
In the visceral mass, what has extensive ciliary tracts and is complex and specialized?
Digestive tract
In visceral mass, what are the 2 kidneys called?
metanephridia
Are mollusk monoecious or dioecious?
Monoecious
Are mollusks hermaphroditic?
some
Mollusk larvae are typically what kind of larvae?
Free-swimming trochophore larvae
What mollusk groups have an additional larvae stage?
Bivalves and Gastropods
For bivalves and gastropods, what is the additional layer called where there is an early foot, shell, and mantle visible and is the only free-swimming stage in some mollusks?
Veliger
What three mollusks have no free-swimming larvae?
Cephaloods, some bivalves, some freshwater and marine snails
What mollusk class is shell-less and wormlike, have an oral shield and a radula, dioecious, and resemble the likely common ancestor of all molluks?
Caudofoveata
What mollusk class is simlar to caudofoveata, no radula or gills, monoevious, and often feed on cnidarians?
Solenogastres
What mollusk class has many plates, known as chitons, dorsoventraly flattened, dorsal shell made of 8 plates, have a radula, mostly dioecious, no veliger stage, head and cephalic sensory organs are reduced?
Polyplacophora
In polyplacophora, what are the chemoreceptive sense organs found near the anus?
Osphradia
What mollusk class is one plate, one caplike shell covering the dorsal side, simple radula, and some organs are serially repeated?
Monoplacophora
In monoplacophora, what is it called when some organs are serially repeated?
Pseudometamerism
What mollusk class has boat feet, also known as tusk shells or tooth shells, mantle is tube shaped, single conical shell open on both ends, and lack ctenidia?
Scaphophoda
What mollusk class has a stomach foot, the larges class of mollusks, includes snails, slugs, conches, limpets, sea butterflies, and only class with a terrestrial species?
Gastropoda
In gastropods, the shell is always what?
Univalve
In gastropod shells, what contains the smallest and oldest whorl?
Apex
In gastropod shells, what is the opening often colored with an operculum?
Aperture
In gastropods, what is the rotation of the shell, mantle, and visceral organs in gastropd developmnt that allows the head to be withdrawn into the mantle cavity?
Torsion
In gastropods, what happens when the anus and mantle cavity opening is above the head?
Increases risk of fouling
In gastropods, what is the spiral winding of the shell and visceral mass, organs become asymmetrically arranged to account for the unbalanced weight?
Coiling
Are gastropods herbivores or carnivores?
Herbivores
What venom do certain gastropods produce from a modified radula?
Conotoxin
How do most gastropods respire?
Ctenidium
Are gastropods monecious or dioecious?
Both
What gastropod subclass is the largest group, most marine snails and some terrestrial/freshwater gastropods and have one pair of tentacles?
Prosobranchia
What gastropod subclass are sea slugs, sea hares, sea butterflies, mostly marine and shallow water, and have 2 pairs of tentacles?
Opisthobranchia
What gastropod subclass are land and most freshwater snails/slugs with a few brackhis and marine species, no ctenidia; mantle cavity has a lung?
Pulmonata
What mollusk class have two valves fused with ligaments on the dorsal side and mostly marine with some living in freshwater and brackish environments, majority are sedentary filter-feeders, no head, radula and minimal cephalization?
Bivalvia
In bivalvia shells, what are the valves held together by?
Hinge ligament
In bivalvia, what is the oldes part of the shell called?
Umbo
In bivalvia, what is a byproduct response caused by irritation caused by foreign objects?
Pearl Production
In bivalvia bodies, where is the viceral mass suspended?
Dorsal Side
In bivalvia bodies, what is formed on the posterior side of the mantle that are modified?
Incurrent and excurrent openings
In bivalvia bodies, how is the foot attached to the visceral mass?
Anteroventrally
In bivalvia bodies, where does gas exchange occur?
Ctenidia and mantle
What kind of relationship do bivalves have with bacteria and dinoflagellates?
Symbiotic
What do bacteria help bivalves in?
Produce cellulaes to help digest wood
What do dinoflagellates help bivalves in?
giant clams get nutrition from photosynthetic products
Are bivalves monecious or dioecious?
Usually dioecious
What kind of fertilization happens in bivalves?
Most external, most freshwater internal
What mollusk class has a head foot, octopuses, squid, cuttlefish, nautilus, and are all marine
Cephalopda
What kind of predators are cephalophods where they feed on small fish, and food is captured with the arms and then brough to the beaklike jaws?
Active
What cephalopod secrete venom from their salivary glands?
Octopuses and cuttlefish
What is the only cephalopod with an external shell?
Nautilus
In other cephalopods like squids, what shell is internal?
Pen
Do octopus have shells?
NO
How do cephalopds move?
Expelling water from mantle cavity through the siphon
What kind of circulatory system do cephalopds have?
Closed circulatory system
What heart in cephalopods move blood through the gills?
2 Branchial hearts
What heart in cephalopds move blood to the rest of the body?
1 systemic heart
How many pairs of gills do cephalopods and nautiloids have respectively?
One pair; two pairs
True or False:
Cephalopods have the largest brain in any invertebrate with multiple lobes
True
What cephalopod is capable of observational learning and tactile exploration?
Octopods
How do cephalopods communicate?
Visual signals; chromatophores
What do cephalopods do for self-defense?
Produce dark ink
Are cephalopods monoecious or dioecious?
Dioecious
In cephalopods do they have free-swimming larvae?
No
What cephalopod subclass has 2 gills and the only surviving member is the Nautilus?
Nautiloidea
What cephalopod subclass are ammonites and all are extinct after the cretaceous?
Ammonoidea
What cephalopod subclass consists of all other living cephalopods and have 1 pair of gills?
Coleoidea
What are mollusks threatened by?
Ocean acidification
