Term
| 2 types of sexual reproduction are: |
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Definition
| monoecious: hermaphrodites (slugs) and sequential herm's (protogyny vs. protandry) Dioecious: sexual selection in heterosexual molluscs. (R-species with many offspring and vs K-species with few large offspring with low mortality)uses hectocotylus |
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Term
| What subclade do tusk shells belong to. Name a synapomorphy of this clade. |
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Definition
| Scaphopoda - has a "spade foot" and lacks gills. Have (and breath through) open ended "tusk"-shaped shell Used for money. [image] |
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Term
| Genus of chiton whose shell is COMPLETELY covered by its mantle. |
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Definition
| Cryptochiton (Gumboot chiton) |
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Term
| One synapomorphy of Bivalva |
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Definition
| 2-part shell; no radula but have ciliated siphon to feed and breathe |
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Term
| Why are brown mussels more common the further south you go? |
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Definition
| Brown better reflects the sun = less heat gain. |
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Term
| Operculum- Aperture- What clade would you find these features? |
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Definition
| Operculum is the "door" that closes the aperture (opening). Found in Gastropods[image] |
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Term
| Example of commensalism in clade gastropoda? |
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Definition
| Polychaete worms living with Limpets in their shells.[image] |
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Term
| 2 defense mechanisms of Nudibranchs |
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Definition
| Aposematic coloration to warn predators. Eat unfired cnidocytes of cnidaria, move them into their cerrata as predator defense. [image] |
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Term
| Name the 5 daughter clades of Mollusca |
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Definition
| -Polyplacophornas (8 plated chitons), -Bivalves (clams mussels, oysters shipworm etc), -Gastropods (slugs and snails, limpets, nudibranchs) -Cephalopods (octopi, squid nautilus) -Scaphopods (tusk shell) |
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Term
| What do squid use to camouflage? |
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Definition
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Term
| How is buoyancy and attitude achieved in cephalopods? |
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Definition
| The chambers in Nautilus act as air compartments with a siphuncle connecting them. Chambers are also present in the "bone" of cuttlefish. |
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Term
| What clade is Tridacna in? |
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Definition
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Term
| What produces/secretes a mollusc's shell? |
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Definition
|
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Term
| What is the composition of the 3 layers of a mollusc's shell? |
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Definition
| Outer: proteinaceous layer Middle: calcium carbonate crystal layer Inner: nacreous layer |
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Term
| Which molluscs has 8 shell plates? |
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Definition
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Term
| Which mollusc has a symmetrical 2 part shell? |
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Definition
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Term
| Only ________ __________ retain the (coiled) shell. |
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Definition
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Term
| Describe early mollusc development and how it moves at that stage. |
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Definition
| Trochophore larvae that move w/ cilia band in midregion. |
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Term
| How are molluscs and annelids related? |
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Definition
| Development: protosomes, trocophore larval stage, Anatomy: body cavity lined with mesoderm |
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Term
| Name the 2 body regions molluscs have and their functions. |
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Definition
| 1. Muscular foot: mostly for locomotion 2. Dorsal visceral mass: contains internal organs and covered with mantle[image] |
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Term
| What does the mantle cavity contain in a mollusc? |
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Definition
| Gills, nephridopore, and anus |
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Term
| What factor can make a mollusc's shell colorful? |
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Definition
| Mineral content in middle layer of shell can make the mollusc colorful. |
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Term
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Definition
| A mollusc's mantle secretes a nacreous layer around a foreign object. |
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Term
| What structures are found on the muscular foot of a mollusc? |
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Definition
| The head with a mouth, and sensory organs are found on the anterior portion of the muscular foot. |
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Term
| What is the unique structure found in a mollusc's mouth? |
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Definition
| A radula: a ribbon-like, belt-shaped, raspy tounge. |
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Term
| How does radula structure reflect diet? |
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Definition
| Herbivores have many small teeth. Carnivore have fewer and larger teeth.[image] |
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Term
| How are Chiton radulas unique? |
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Definition
| Contain iron oxide, since they lick algae off rocks.[image] |
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Term
| What does this photo show?[image] |
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Definition
| A moon snail and it prey (clam) |
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Term
| How are cone snails' radulas specialized? |
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Definition
| Cone snails havs a ciliated siphon in its mantle that is chemical senistive, and modified radula that is harpoon-like to inject calicum channel blocking neurotoxins into their prey.[image] |
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Term
| How do mussels in rivers increase increase reproductive sucess? |
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Definition
| Mussels in rivers use a minnow-like mantle margin to attract fish. When the arrives, the mussel releases its offspring which parasitize the fishes gills. The glochidia recieves protection and is dispersed further than otherwise by this parasitism. [image] |
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Term
| How do river mussels's offspring hold onto their host fish, and what benefit do they receive from the fish? |
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Definition
| With teeth that bite into gill filaments by contracted adductor muscles. The offspring recieve protection and upstream transport. [image] |
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Term
| How is Darwin's concept of sexual selection observed in male dioecious cephlapods? |
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Definition
| Many male cephlapods have hectocotylus arm that collects sperm from its reproductive tract until copulation. Upon copulation arm detaches in the female's reproductive opening, blocking other males from reproducing with her. |
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Term
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Definition
| Starting reproductive life as a female. When the organism reaches a size in which it can compete with males sucessfully, the gender changes from female to male. |
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Term
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Definition
| When an organism starts its mature life as male, then becomes a female is an example of protandry. |
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Term
| What is the benefit protogyny? |
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Definition
| An organism can be producing offspring throughout its lifetime, with male producing more offspring due to the greater numbers of fertilization events in which they can participate in. |
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Term
| What is the benefit of protandry? |
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Definition
| If there's no male-male competition, then being big as a female = leaving more young in lifetime. |
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Term
| Which mollusc subclade has a spade foot? |
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Definition
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Term
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Definition
| Burrow spade foot into the soft ocean bottom and feed on detritus caught in their tentacles. |
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Term
| How do scapohods respire? |
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Definition
| Beating cilia to drive water in mantle cavity through the holes at each end of their shell. Tusk shell organism lack gills. |
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Term
| What mollusc was used as money by Native Americans? |
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Definition
| Scaphopods -- tusk shells |
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Term
| What mollusc has >2 segments, how many, and why? |
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Definition
| Polyplacophorans have 8 jointed shell segments which allow them to conform to irregular intertidal surfaces.[image] |
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Term
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Definition
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Term
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Definition
| A home scar refers to specfic depression in a rock a chiton or limpet fits into. |
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Term
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Definition
| By beating cilia through their mantle cavity, across a pair of gills each located in one of 2 lateral mantle cavity grooves. Ex: gumboot chiton.[image] |
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Term
| What is unique to the radula of chitons? |
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Definition
| Iron in largest teeth aids in licking algae off rocks. |
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Term
| How do chitons reduce predation? |
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Definition
| Extending beyond their shell is mantle which is often covered with defensive bristles.[image] |
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Term
| Name 2 sister clades which have lost their cephalization? |
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Definition
| Bivalva and scaphopoda have lost their radula. |
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Term
| How do bivalves respire and eat? |
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Definition
| Bivalves respire via ciliated incurrent and excurrent siphons which pumps oxygen and food rich water into their shell. Food is filterd by palps. |
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Term
| Why are the adductor muscle scars on a clam so obvious? |
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Definition
| The adductor muscle scars are so obvious because this was the location at which the adductor muscles attached to the clam shell with the purpose of opening and closing the clam's shell. [image] |
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Term
| Are older or more recent fossils more accurately carbon-dated? What does the graph look like? |
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Definition
| More recent fossils are: as the ratio of C14 to C12 gets closer to zero, so little C14 remains that the margin for error increases signifigantly.[image] |
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Term
| Give some synapomorphies of clade Mollusca |
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Definition
1) start off as trochophore larvae w/ a band of cilia for movement.
2) 3-layer shell secreted by
3) mantle |
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Term
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Definition
| Simple eyes found on scallops which watch for predators.[image] |
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Term
| What is the typical environment for a mussel and how are they anchored to that environment? |
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Definition
| Rocky intertidal (and subtidal), attaching with byssal therads secreted by a gland in its foot. |
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Term
| How do non-sessile species of bivalves, escape predators? |
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Definition
| Rapid contraction of adductor muscles allow for jet propulsion in bivalves to escape predators. |
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Term
| What clade and genus is this organism:[image]
What is their greatest predator? |
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Definition
Clade Bivalve, genus Tridacna (giant clam).
Humans are the giant clam's greatest predator. |
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Term
| What are adapations of burrowing bivalves which live in a hard medium? |
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Definition
| Shipworms: bores into rock or wood, & have reduced shells usually used for abraiding their inhabited surface
Sandstone borer: bores into sandstone with a rough posterior shell and chemical secretions.
Here is a picture of a sandstone borer.[image] |
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Term
| What are adaptations of bivalves which inhabit soft mediums? |
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Definition
| 1) well developed shells for protection
2) long and thin siphons for feeding, breathing and waste removal due to their immobility. This is an example of a long siphoned clam.[image] |
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Term
Scientific name of chiton whose mantle
PARTIALLY grows over shell. |
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Definition
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Term
| 90% of molluscs are in which subclade? |
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Definition
| Gastropoda - "belly-footed" snails and their allies. |
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Term
| What's the gastropod's "opening" & "door" called. |
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Definition
| aperture = opening
operculum = door[image] |
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Term
| Name the molluscs that have a shell that rotates into a coil. |
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Definition
| Gastropoda & ancestral Cephalopoda (a synapomorphy they share) |
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Term
| Name the developmental characteric of gastropods involving rotation. |
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Definition
| Torsion. The mantle cavity is posterior in embryos, then the viseral mass rotates 180° bringing the mantle cavity above their head. |
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Term
| Slugs undergo uncoiling. What is this? |
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Definition
| Detorsion. An evolutionay reversal of the 180° rotation of their immediate ancestors. |
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Term
| The limpet clade is ...? What's unusual about their shell? |
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Definition
| Limpets are Gastropoda. Their shell ISN'T coiled, but cone shaped. [image] |
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Term
| Name this mollusc, its clade and a key characteristic to reduce competition with other organisms in its habitat. [image] |
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Definition
| Owl limpet. Gastropoda. The design is compromised of prying ability vs. hydrodynamics. A squat offset shape allows it to bulldoze competitors out of its habitat for better access to food. |
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Term
| Name the clade, name, and a unique morpological characteristic for defense of this mollusc:[image] |
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Definition
| Gastropoda. Keyhole limpet. This gastropod can raise its girdle upward to keep starfish from eating it. |
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Term
| Which clade of molluscs have diverse colors and patterns in tropical regions and why? |
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Definition
| Gastropoda. Disruptive coloration can aid in camoflaging in tropical areas of high predator density |
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Term
| Name the clade of this gastropod which glues other shells to itself and why it does this.[image] |
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Definition
| Gastropoda (decorator snail). This gastropod glues shell to itself to look different and to make it more difficult to swallow. |
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Term
| Slugs and what lack shells in what clade?[image] |
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Definition
|
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Term
| What is the clade and name of this mollusc?[image] |
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Definition
| Gastrpoda, sea hare (Aplysia) |
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Term
| What do nudibranches prey on, what is sequestered in projections on their back, and what purpose does it serve? |
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Definition
| Nudibranches prey on cnidarians which carry nematocysts. The nematocysts are then sequestered in cerrata on the nudibranches back. This serves as aposematic coloration to warn predatory fish aganist eating them. |
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Term
| Did nudibranches evolve aposematic coloration to benefit the fish that prey on them? |
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Definition
| No. This trait serves the nudibranch to enhance its survival chance, and was selected for. |
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Term
| Name the clade, name and unique features and adaptations of this animal:[image] |
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Definition
| Cephlpoda. Squid. Highly developed eyes, large brain, keen predator, 3 hearts, beak-like jaws,2 long tentacles with sucker pads (with teeth in larger species), skin pigment varitability due to chromatophores, |
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Term
| Where do eyes arise from? |
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Definition
| A common ancestor: eyes evolved once with the pax-6 gene. |
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