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68 Cards in this Set
- Front
- Back
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What are some characteristics of the phylum Mollusca? |
- no constraints on body plan (DIVERSE) - 100,000 extant species - microscopic -> large - terrestrial, aquatic, fw - open circulatory system |
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What are some physical characteristics of molluscs? |
- bilateral symmetry - muscular foot - mantle: drapes over organism - mantle cavity - shell of calcium carbonate - gills - coelom - radula - metanophridia |
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What are the seven classes below phylum Mollusca? |
- Aplacophora: deepwater, no shells - Monoplacophora: deepwater limpets - Polyplacophora: chitons - Gastropoda: snails/slugs, largest number of species - Bivalvia: bivalves - Scaphopoda: tusk shells - Cephalopoda: swimming predators |
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What are the three subclasses in Class Gastropoda? |
- Prosobranchia: snails exhibiting torsion - Opisthobranchia: sea slugs, marine, hermaphroditic, DETORTED - Pulmonata: mostly land snails and slugs, mantle modified into lung |
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What are the three orders of Subclass Prosobranchia? |
- Archeogastropoda - Mesogastropoda - Neogastropoda |
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What are the characteristics of Archaeogastropoda? |
- herbivore - pelagic - simple nervous system - 2 gills - no siphon - no proboscis |
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What are the characteristics of Mesogastropoda? |
- herbivore - pelagic - moderate nervous system - 1 gill - some w/ siphons, some w/o - no proboscis |
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What are the characteristics of Neogastropoda? |
- predators - direct development - complex nervous system - 1 gill - have siphon - have a proboscis |
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What are the orders of subclass Opisthobranchia? |
- Cephalaspidea - Anaspidea - Thecosomata - Gymnosomata - Sacoglossa - Notaspidea - Nudibranchia |
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What are Cephalaspidea? |
bubble snails |
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What are Anaspidea? |
sea hares |
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What are Thecosomata? |
pelagic pteropods w/ shells - sea butterflies |
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What are Gymnosomata? |
pelagic pteropods w/o shells - eat sea butterflies |
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What are Sacoglossa? |
herbivorous slugs - use chloroplasts from algae |
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What are Notospidea? |
aggressive limpets |
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What are Nudibranchia? |
colorful sea slugs |
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What are the four subclasses to bivalves? |
- Palaeotaxodonta: primitive, protobranch gill - Cryptodonta: primitive, protobranch gill, some w/ reduced gut - Pteriomorpha: mussels, scallops, oysters; attach by byssus thread - Heterodonta: clams and shipworms; long siphons |
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What is the single species represented in Class Scaphopoda? |
- tusk shells - foot used for burrowing |
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What are the two subclasses in Class Cephalopoda? |
- Nautioloidea: chambered nautilus, shell for buoyancy, 2 gills - Coleoidea: squids and octopods |
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What are the three orders in Subclass Coleoidea? |
- Decapoda: squids, 8 short, 2 long arms, mantle w/ fins - Vampyromorpha: deep sea squids - Octopoda: octopods, 8 short arms, no long arms, no fins on mantle |
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What is a HAM? |
- not a delicious piece of pork - Hypothetical Ancestral Mollusc |
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What are some characteristics of the HAM? |
- shell: to protect from beating waves - foot: suction cup and slow locomotion - retractor muscles - nerve collar w/ 4 pairs of nerve cords - visceral mass: suspended in blood space - coelom: pericardium - nephridium: uses heartbeat to generate urine - heart: 3 chambered |
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What is the importance of the toothed hinge and elastic resilium in bivalves? |
- toothed hinge: prevent two halves from rotating - elastic resilium: control opening |
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What is interesting about Opisthobranchs? |
- detorted their shells, straigthend mass but not nervous system (still torted) |
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What kind of feeders are bivalves? |
- filter feeders |
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What do cephalopods use their foot for? |
- modified to funnel for pushing water; jet propulsion |
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What do cephalopods use their radula for? |
- modified to beak for crushing prey |
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What do cephalopods use their mantle for? |
- cloak/water bag for directing jet propulsion |
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Do cephalopods have an open or closed blood vascular system? |
CLOSED, no hemocoel |
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Do cephalophods have a complex sensory system? |
YES - can change body coloring (chromatophores) - can change shape (mimic seaweed, coconuts) - smartest inverts |
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What is a defining feature of molluscs? |
SHELL - organic material (up to 30%): collagen/protein (conchiolin) |
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What are the three layers of the shell of molluscs? |
1 - Periostracum: higher amount of protein (black exterior on mussel shell) 2 - Prismatic layer: crystalline CaCo3, crystals laid over thin proteinaceous material 3 - Nacreus layer (inside): emorphus CaCO3, opaline, "mother of pearl" NO MOLLUSCS DOES THIS IN EXACTLY THE SAME WAY (some inside out) |
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How is a pearl produced? |
- nacreus layer secreted over disturbance in shell and built up over time |
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How are the layers laid down? |
by ephethlium of the mantle (inside -> out) - gastropods shell swirl - bivalves do it by going outward |
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Are the periostracums of burrowing bivalves thick or thin? |
shawty THICK - covered in protein bc they often secrete acid and need protection (collagin) |
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What are characteristics of grazer molluscs? |
- herbivorves, scrape off microalgae - HAM evolved in rocky intertidal (like chitons) and took full advantage by grazing - radula: tongue of teeth (ribbon of teeth on odontophore - moved by cartilage) - crystalline style (in style sac): enhance digestion of herbivorous material - digestive gland: outpocket of gut (blind end sac) where digestion happens slowly |
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What are muscle groups that control odontophore? |
- radula retractor and protractor - odontophore retractor and protactor |
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What is the function of the radular sac? |
to produce new radula teeth - teeth destroyed by repeated exposure over rock - odontoblast: make new teeth |
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Radula are found in all groups of molluscs EXCEPT? |
Bivalves |
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Radula modified in: |
Cephalopods: beak Neogastropods: harpoon darts (cone snails - Conus) |
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Where will you see crystalline styles? |
In gastropods and bivalves |
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What is the crystalline style made of? |
alpha-amhylase - acts on starches, converts complicated polysaccharides to sugars - naturally crystalize, grows outwards, cilia beat so that rod turns around and around, pushed up against wall of gut at gastric shield (made of chitin:hard), pieces of rod fall off and dissolve in gut - smallest particles in missing area fall into sorting area, large particles get conveyed out into gut and passed into fecal material, tiny particles move to digestive gland |
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what is the method of exchange across bivalves? |
Counter-current exchange |
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what kind of gills do bivalves have? |
lamellibranch |
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what are the names of the pores between the lamelli? |
- ostia |
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t/f - bivalves are sponge wannabees |
t, filter feeders |
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what does the mucous produced by bivalves (heterodont and pteriomorph) look like and what is it for? |
- a net covering lamillae moved by cilia (muco-suspension feeding), captures particles, shoved in mouth, digestion begins |
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Protobranch gills were originally used for? |
- respiration modified to lamellibranch |
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who does the septabranch gill belong to? |
- anomalodesmata very small predatory clams, feed on copepod use gill to pull prey into valve and beat prey to death with foot |
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what is the order of blood circulation in molluscs? |
heart - hemocoel (over brain) - vessel - gill - repeat |
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what is the exception to presence of hemocoel? |
- cephalopods (predators, need closed BVS) |
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what pigments are found in blood? |
- respiratory pigments: hemocyanin (contain Cu) hemoglobin (contains Fe) enchances ability to hold oxygen (simplest - just plasma more complex - plasma + pigments most complex - plasma + pigments in cells associate pigments w/ tissues that need them - myoglobin) |
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what kind of blood to most inactive animals? |
plasma, enhanced based on activity |
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where does excretion take place in molluscs? |
- heart (provides pump) - pericaridium (membrane thru which wastes is passed and water) - nephridium/kidney (absorbs organic material and eliminates waste) |
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what happens when animal lives in aquatic environment? |
- preferred nitrogenous waste = ammonia (1 N) extremely toxic w/ high pH |
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what must happen to urine for it to not do damage? |
DILUTE urine |
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why is kidney small? |
- small amount of peeing all the time |
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what about kidneys in terrestrial environments/in animals that eat meat? |
carnivores - dealing with more N waste larger kidney, concentrated urine - urea 2 N - uricia 4 N - guanine 5 N |
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what kind of kidneys are found in molluscs? |
depend on what it eats and where it lives (terrestrial/carnivore - larger, conc urine aquatic - smaller, dilute urine) |
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what is the main reproduction method of molluscs? |
- sexual diecious and hermaphroditic, pretty much all kinds of methods found |
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what is interesting about cropitudula fornicada? |
- babies metamorphizese in chemical cue, first one to settle = female, ones on top after her = male, ones in between the two are in between, males have long penises to extend to females, |
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what molluscs free spawn? |
- oysters (fertilization occurs in water column) |
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what molluscs brood? |
- sperm caught by females, developed in mantle cavity >parasitic glochidium larvae of freshwater mussel, female turns over to attract fish, larvae grab onto gill of fish and clamp down, absorb epithelium of fish, fall off and filter feed after metamorphose > emergent larvae in chitons - trochophore: looks like top, cilia around middle and on top and bottom, feeds on plankton, turns into characteristic mollusc larva - veliger larva |
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how are molluscs and annelids linked? |
TROCHOPHORE LARVAE |
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what is the superphyla that links molluscs and annelids |
Locotrophocore |
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what makes up the veliger larvae? |
- velum: collects particles of foods grows and grows - veliger for gastropods and bivalves, both have velur lobe invoolved in collecting plankton and swimming - both have statocysts/eyes for sticking up in water column - foot for swimming, when it touches rock or another oyster it settles (bivalves) |
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t/f not all gastropods produce planktonic larvae |
t, some produce egg masses |
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t/f molluscs show affinity to annelids |
t, evidence in embryology and molecular biology |
