Chapter 6 - Molluscs Flashcards
today we will be learning abt the molluc (117 cards)
1
Q
How many living species of Mollusca are there? How many fossil species?
A
Over 90,000 living species; 70,000 fossil species
2
Q
Enumerate some of the common shared features of molluscs
A
- Radula,
- large muscular foot or tentacles for movement,
- mantle for respiration and shell secretion
3
Q
Which of these are not nutritional modes of molluscs:
a. Filter feeder
b. Parasites
c. Herbivorous grazer
d. Detritus feeder
e. Predaceous carnivore
f. None of the above
A
f. None of the above
4
Q
Give the scientific name of a chiton
A
Tonicella lineata
5
Q
Give one characteristic (apomorphy) of Caudofoveata
A
Calcareous spicules form scales
6
Q
What is the clade containing only Caudofoveates and Solenogasters? What is the clade that contains them and Polyplacophorans?
A
- Aplacophora
- Aculifera
7
Q
What are some molluscs considered as pests?
A
Burrowing shipworms, snails and slugs
8
Q
True or False: The head-foot region of molluscs contain the feeding, sensory, excretory, reproductive, and locomotry organs.
A
False
Excretory and reproductive organs are not found in the region
9
Q
Found in all molluscs except bivalves and some solenogasters
A
Radula
10
Q
Up to how many teeth can be found in the radula?
A
250,000
11
Q
Describe the radula
A
Protruding, rasping, tongue-like organ that is a ribbon-like
membrane with rows of tiny teeth
12
Q
The portion of the radula that supports the teeth and is cartilaginous is called the:
a. spicules
b. visceral mass
c. teeth
d. odontophore
This ain’t in the PPT but it’s cool to know
A
d. odontophore
13
Q
Which of these are used by molluscs for attachment to substratum?
a. mantle groove
b. foot
c. pallium
d. glochidia
A
b. foot
14
Q
Name some of the modifications of the mollusc foot
A
- Attachment disc of limpets
- Hatchet foot of clams
- Siphons for jet propulsion in cephalopods
15
Q
Yellow and pink marine snail
A
Calliostoma sp.
16
Q
Example of nudibranch in the PPT
A
Chromodoris sp.
17
Q
Example of an octopus in the PPT
A
Octopus briareus
18
Q
What do free-swimming forms of the foot use for locomotion?
A
modified wing-like or fin-like
parapodia
19
Q
What secretes and lines the shell?
A
Mantle
20
Q
outer horny layer of the shell protecting underlying layers from eroding burrowers, with growth occurring only at the margins of the shell
A
Periostracum
21
Q
What does the middle prismatic layer consist of?
A
densely packed prisms of calcium carbonate
laid on protein matrix
22
Q
Shell layer next to the mantle, secreted continuously by the mantle surface so it increases in thickness as the animal grows
A
Inner nacreous layer
23
Q
What type(s) of reproduction can be found in molluscs?
A
Most dioecious, some hermaphroditic
24
Q
Mollusc larva
A
trochophore
25
What mostly ancestral trait do trochophore larvae directly undergo?
metamorphosis into a small juvenile
26
molluscan intermediate larval stage in many gastropods and bivalves
veliger
27
What are veligers hatched with?
beginnings of a foot, shell, and mantle
28
Which types of molluscs s have no free swimming larvae, with only juveniles hatching directly from eggs?
* Cephalopods
* some freshwater bivalves
* snails
29
Christmas tree worm
*Spirobranches spinosus*
## Footnote
Notable for having a trochophore similar to Mollusca, indicating common ancestry among molluscs and annelids
30
Type of snail whose veliger was shown in the PPT
*Pedicularia* sp.
31
Other name for Class Caudofoveata
Chaetodermomorpha
32
class consisting of about 120 species of worm-like, marine organisms ranging from 2 to 140 mm long
Class Caudofoveata
33
What does Class Caudofoveata mainly eat?
microorganisms and detritus
34
How do most species under Class Caudofoveata burrow and orient themselves?
burrow and orient vertically with terminal mantle cavity and gills at entrance
35
True or False: Solenogasters have radula, gills, and a foot.
False
| Solenogasters have no radula, nor do they have gills.
36
midventral, narrow furrow found in the foot of Class Solenogasters
pedal groove
37
Other name for Class Solenogasters
Neomeniomorpha
38
What feeding habit does Class Solenogasters exhibit?
Do not burrow but are bottom dwellers and feed on cnidarians
39
True or False: All solenogasters are hermaphroditic.
True
40
Caudofoveate example in the PPT
*Chaetoderma elegans*
41
What is visible on the skin of solenogasters and caudofoveates?
spicules
42
Class of chitons
Class Polyplacophora
43
What is the body structure of Class Polyplacophora?
Generally flattened dorsoventrally with a convex dorsal surface that has seven or eight articulating limy plates
44
Where do chitons tend to live?
rocky surfaces along intertidal regions; some found at great depths
45
What reinforces chiton radula?
magnetite
46
What is the function of magnetite?
Reinforces the chiton radula to scrape algae from rocks
47
Mossy chiton
*Mopalia muscosa*
48
Class of molluscs previously deemed extinct
Class Monoplacophora
49
What are the traits of Class Monoplacophora?
* radula
* rounded shell
* creeping foot that resemble limpets
50
How many living species of Gastropoda are there?
Over 70,000
51
True or False: No snails are specialized for burrowing
False
## Footnote
Some snails are specialized for climbing, swimming, burrowing
52
Describe gastropod shells
A one-piece univalve that can be coiled or uncoiled
53
What is the smallest and oldest part of the gastropod whorl?
Apex
54
What is the central axis of the gastropod shell?
Columella
55
The structure of the shell that covers the shell aperture or entry
Operculum
56
Whelk species that shows the parts of a gastropod shell
*Busycon* sp. (*Busycon contrarium* and *Busycon carica*)
57
True or False: Some snails release toxic secretions by using stolen cnidocytes or forming poison harpoons to catch prey
True
58
This species of snail has a modified operculum with a sharp spike to give an active blow to possible predators
*Strombus* sp.
59
What is the scientific name of the parasitic flatworm that infests snails of the genus *Succinea*?
*Leucochloridium paradoxum*
60
How do snails detect potential prey?
by detecting chemical cues from metabolic waste
61
Give the scientific name of the red abalone
*Haliotis rufescens*
62
What is the scientific name of the moon snail?
*Polinices lewisii*
63
What genus of snail feeds on fish, worms, and other molluscs using a lethal sting to secure prey?
*Conus*
64
*Conus* snails have a modified radula with forms a harpoon with poison gland, containing venom called ____
**conotoxin**
65
Why are some species of*Conus* valuable for research?
their conotoxin can be lethal to humans, so they can help in the research of cell receptors and ion channels of nerve cells
66
True or false: Copulation in monoecious gastropods can involve exchange of spermatozoa
True
67
What type of fertilization do most snails have?
Internal fertilization
## Footnote
Primitive reproductive feature is external fertilization forming
free swimming trochophores
68
Describe how gastropods lay their eggs
Eggs are laid in clusters (sometimes in tough capsules)
69
True or False: Most freshwater snails are ovoviviparous?
True
## Footnote
Meaning that the eggs develop within the snail body and are not laid
70
Name the three traditional sub-classes of Gastropoda
Prosobranchia, Opisthobranchia, Pulmonata
71
What are the Prosobranchs?
Mostly sea snails, but also include freshwater and land snails
## Footnote
Examples are periwinkles, horse conch, limpets, and the flamingo tongue snail
72
Give the scientific name of a limpet
*Patella* sp.
73
What is the scientific name of a flamingo tongue snail?
*Cyphoma gibbosum*
74
These are two pairs of tentacles of Opisthobranchs with one modified to increase chemo-absorption
rhinophores
75
Are the Opisthobranchs all monoecious or dioecious?
Monoecious
76
What differentiates the Opisthobranchs from the other gastropods?
## Footnote
Hint: it's in the shell
Shell is reduced or absent
77
Give the scientific name of a sea hare
*Aplysia dactylomela*
78
What is the ancestral respiratory organ of molluscs?
Ctenidia
79
Pulmonates have lost their ancestral ctenidia, what took its place as a respiratory organ?
The vascularized mantle wall which is now a lung
80
How do aquatic species of Pulmonates differ from land species?
* Aquatic species have one pair of nonretractile tentacles with eyes at the base
* Land species have two pair of tentacles with the posterior pair having eyes
81
What's the scientific name of a banana slug?
*Ariolimax columbianus*
82
What are the other names of Bivalvia?
Pelecypoda or "hatchet-foot"
83
How do most bivalves feed?
As sedentary filter feeds which depend on currents produced by their cilia
84
What do bivalves lack?
Head, radula, and other aspects of cephalization
85
True or False: No bivalves are found in freshwater
False
86
Give the scientific names of some bivalves in the PPT
* *Mytilus edulis*: Mussel
* *Chlamys opercularis*: Scallop
* *Tagelus plebius*: Stubby razor clam
* *Tridacna gigas* and *maxima*: Giant clam
* *Aequipecten irradians*: Surface-dwelling scallop
87
What holds the two valves of bivalves together?
Hinge ligament
88
The oldest part of a bivalve shell that grows outward in rings
Umbo
89
True or False: A mollusc that has its mantle wrapped around the viscera and a shell that is a tube is in the class Scaphopoda
True
## Footnote
Also known as the tusk or tooth shells
90
True or False: Scaphopods have gills like other molluscs but also can breathe through their mantle
False, gaseous exchange occurs via the mantle but they lack gills
91
What are the mucus-covered tentacles of scaphopods called? What is their function?
**Captacula**, it functions to catch food
92
Other than gills, what other feature do scaphopods lack?
Eyes and other sensory features
93
Give the scientific name of a scaphopod
*Dentalium* sp.
94
How are chromatophores controlled in cephalopods?
contractions of muscle fibers attached to cell boundary
95
spermatozoa packaged in spermatophores and stored in sac that opens up to mantle cavity
male seminal vesicle
96
How is the foot different in cephalopods compared to other classes?
Foot merged with head region and modified for expelling water from mantle cavity
97
True or False: Cephalopods are sensitive to the salinity of the waters they live in.
True
98
One arm of male cephalopods modified as intromittent organ
hectocotylus
99
What is the function of the hectocotylus?
remove spermatophore from male mantle cavity and insert to female oviduct
100
What do Nautiloidea and Ammonoidea have in common?
* Gas chambers for buoyancy
* Shell has transverse septa w/ sequential chambers
* Siphuncle
101
A cord of living tissue that connects chambers to visceral mass
Siphuncle
102
In which chamber of nautiloid and ammonoid shell can the living animal be found?
Last chamber
103
True or False: Nautiloidea has 1 pair of gills while Coloidea has 2
False
| Nautiloidea has 2 pairs of gills while Coloidea has 1
104
What do Nautiloidea tentacles have?
adhesive secretions
105
What can be found beneath the head of Nautiloidea?
funnel, mantle cavity, and visceral mass sheltered by shell
106
Which era were Ammonoidea species prevalent? By which era were they extinct?
Prevalent during Mesozoic, extinct at end of Cretaceous
107
What are the traits of Ammonoidea shells?
Chambered shells with complex and drilled septa
108
Order of Coloidea with a shell that is small, curved, and entirely enclosed by the mantle
Sepiodea
109
Give a scientific name for a cuttlefish.
*Sepia latimanus*
110
Which orders of Coloidea evolved from straight-shelled ancestors?
Myopsida, Degopsida, Octopoda
111
Squid shell
Pen
112
What are the traits of the squid shell?
thin proteinaceous strip enclosed by mantle
113
Give a scientific name for a squid.
*Loligo vulgaris*
114
Order of deepwater vampire squids
Vampyromorpha
115
What are the traits of the octopus shell?
none lol it doesn't have one
116
Which eras did most Nautiloidea populate the Earth?
Paleozoic and Mesozoic eras
117
What other type of animals are cephalopod eyes similar to?
Vertebrates
