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79 Cards in this Set
- Front
- Back
Describe a hypothetical ancestor (HA) Mollusc |
aquatic, eucoelomate, protostome with a shell secreted by a mantle which covers the visceral mass |
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The broad and flat, ventral foot is for what is HA? |
Movement over hard substrates. |
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The head of the HA mollusc contains what |
eyes and tentacles |
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Posteriorly, the mantle cavity encloses what in the hypothetical mollusc? |
a pair of gills |
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The buccal cavity of the hypthetical mollusc contains what? |
file like rasping organ, the radula |
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Differences in class gastropoda from the HA |
torsion of the viscerall mass |
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Result of torsion in class gastropoda? |
resulting in a new position of the mantle cavity and coiling of the shell (and viscerall mass contained within it). Also loss of organs on the right side in some forms. (loss of bilateral symmetry)
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Difference from HA in class Polyplacophora |
Body is dorsoventrally flattened. Shell consists of 8 overlapping plates. Small head mantle cavity is two shallow troughs on each side of the foot. (reduced) |
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Differences from HA in class Bivalvia |
Body is compressed, enclosed in a bivalve shell. Shell is hinged dorsally. Small head, large gills. The radula is lost. Foot is used for digging. |
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Differences in HA for class Cephalopoda |
Foot has been divided into arms used for grasping prey. Nervous system is highly developed in concentrated anteriorly, forming a brain. |
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Organisms covered in class Gastropoda |
Haliotis, Cypraea, Strombus, Crepidula, Conus, Busycon, Hexabranchus, Helix, Achatina, Garden slugs, Helisoma |
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Organsims in class Polyplacophora |
Katharina |
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Organisms in class Bivalvia |
Lampsilus, Anodonta, Tridacna, Corculum, Saxidomus, Venus, Solen, Dreissena, Bankia |
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Organisms in class Cephalopoda |
Nautilus, Placenticerus, Amaltheus, Sepia, Illex, Octupus |
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The Trocophore larva occurs where? |
Polychaete worms, marina molluscs and some other protostome phyla. |
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The epithelium of the trocophore larva supports the: |
prototroch |
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Does the trochophore larva contain a mouth? |
Yes |
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What does the trocophore transform into in gastropods and bivalves? |
Veliger Larva |
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The prototroch of the trocophore larva expands and forms what? |
ciliated lobes of the velum |
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In gastropods, torsion occurs during what stage? |
veliger stage |
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What is an operculum? |
gill cover. Saves the mollusc from water loss. |
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What moves the veliger larva until the foot is large enough? |
The velum propels the larva |
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Trocophore larvae that are non motile are held where? |
the gills |
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Trocophore larvae that are non motile transform into what? |
glochidium larvae |
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Where may glochidium larvae be found? |
parasatizing fish and feeding on their tissues before dropping off and burrowing. |
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In class gastropoda, what protrudes the aperture |
head and foot |
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How can you tell if a gastropod is sinistral or dextral? |
Holding the shell with the aperture facing you and apex up, if the aperture opens to the left of the axis it is sinistral. If it is right than dextral. |
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The terrestrial garden snail, helix sp is a member of what subclass of gastropods? |
pulmonate gastropods |
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The garden snail, heliz sp contains what instead of gills |
the mantle cavity modified into lungs |
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the head of the garden snail bears what? |
tentacles and eyes (posterior bearing the eyes and anterior tentacles.) |
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Where is the pneumostome (opening of the lung) located in the garden snail? |
The right side |
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where is the anus located in the garden snail? |
near the pneumostome, posterior to the head |
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the anteroventral mouth in the garden snail contains what? |
Radula, composed of chitinous teeth. (Graze algae from substrates) |
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The terrestrial african land snail, achatina, and the pond snails, Lymnaea have what kind of shell? |
tall spiral |
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what kind of shell does the garden snail have? |
flattened spire |
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Ramshorn snails, helisoma have what kind of shell? |
flat, planispiral |
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Lymnaea and Helisoma are both... |
aquatic and lack an operculum |
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Where do conches, strombus occur? |
tropic seas |
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cone shells, conus, have modified radula that do what? |
produce poison darts which are used to kill prey. |
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Whelks, Busycon, feed primarily on what? |
other molluscs |
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Sea slugs or nudibranchs have what kind of symmetry? |
secondary bilateral symmetry |
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Each valve of the bivalve shell is in what position. What attaches it? |
lateral and covers each side of the animal. Both attached by the dorsal hinged ligament. |
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What is the umbo? |
bulge near the hinged ligament that represents the origin of the valves. |
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Where are the siphons located in bivalves. |
Ventral incurrent siphon and dorsal excurrent siphon. In some species they are encased into a single elongate siphon. |
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Why does the opening of the incurrent siphon have pronounced papillae projecting from it's edges. |
Choosing particles to uptake. |
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The opening and closing of the valves in controlled by what? |
the interaction of the elastic hinge ligament with the posterior and anterior adductor muscles. |
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In bivalves, respiratory water current which also carries food particles enters through what and then? |
enters the incurrent siphon and passes through the gills where food particles are deposited. The water flow then makes a u-turn and leaves the mantle cavity through the excurrent siphon. |
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In bivalves, how are food particles taken up by the animal? |
After deposited on the gills, food particles are transferred by ciliary action to food grooves on the free end of the gills , to labial palps, to the mouth. |
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How is oxygen taken up in bivalves? |
by blood in the gill capillaries from incurrent flow |
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How is carbon dioxide eliminated by bivalve animals? |
released into and passed out by the excurrent flow |
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What does the pericardial cavity contain? (Bivalves) |
a ventricle which wraps around the intestine, which passes through the pericardial cavity. |
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The ventricle of bivalves receives blood from what? |
membranous sac-like atria. |
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What is the ositum? (Bivalves) |
the opening by which the atrium empties into the ventricle. |
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Most mollucs (except squid) have what kind of circulatory system? |
open circulatory system |
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What makes up the bulk of the visceral mass in bivalves? |
The liver and the gonad |
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In squids, where are the foot and head located? |
they are in close proximity, projecting from the tubular muscular mantle which encloses the viscera |
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The foot has been modified into what in squids |
as a ring of arms which encloses the buccal mass. |
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The ring of arms is differentiated into what in squids? |
a single pair of long tentacles bearing suckers at the end and eight shorter arms bearing suckers all over. |
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The fins of the squid project from what side of the mantle. |
anterior side. The mantle is also on the dorsal part of the squid. |
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Purpose of the fins for squids? |
stabilization and locomotion |
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Which direction do squids swim? |
ventral surface foremost |
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What causes the jet stream of the siphon in squids? |
Contraction of the mantle muscle forces water out of the siphon |
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When the squid is fleeing, what direction does it swim? |
dorsal foremost |
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What regulates the passage of water out of the mantle cavity of the squid? |
siphon valves. |
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function of the articulating ridges on each side of the squid. |
help seal the edges of the mantle to the head, preventing pressure loss when water is being expelled through the siphon. |
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Where is the ink sac in the squid? |
deep in the rectum and anus along the posterior surface of the liver |
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Purpose of the siphon retractor muscle? |
attach the dorsal part of the siphon to the dorsal part of the mantle. |
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What type of hearts do squids have? |
Branchial and systemic |
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Location of the gills in the squid? |
On both sides of the liver with the branchial hearts at their base. The kidney also lies between them. |
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The branchial arteries of the squid carry which type of blood |
deoxygenated blood |
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What does the systemic heart do? |
pumps oxygenated blood to the rest of the body. blood passed to the systemic hearts from the branchial veins. |
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What is the hectocotylus arm in squids? |
In male squids, the arm reaches into his mantle cavity, removes a spermatophore and deposits it into the mantle cavity of the female. |
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What is the pen? |
In squids, it is the only remnant of the shell. It is chitinous. |
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In squid, what does the oesophogus pass through? |
The brain |
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In cuttlefish, Sepia sp. What is the pen made out of? |
the pen is calceriouos |
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The octupus bear 8 of what? Do they have fins? |
8 arms. No, indicating for stable lifestyle. |
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The small first chamber of the most ancient cepholopod, Nautilus is? |
The Protoconch |
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What is the siphuncle? Septa? |
In Nautilis(cephalopod) it connects all of the chambers to the protoconch. Septa separate the chamber. |
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What is the suture? |
The junction of the septum with the inner wall of the shell in nautillus. (cephalopods) |