Module 4 Mollusca Flashcards
1
Q
Second largest animal phylum
A
Mollusk
2
Q
True or False: Mollusks are mostly marine phylum with 90000 described species
A
True
3
Q
\True or False: Mollusks are predominant phylum in marine environments and only one group (snails and slugs) has species adapted for land
A
True
4
Q
True or False: All mollusks are soft-bodied
A
True
5
Q
True or False: All mollusks are eucoelomate
A
True
6
Q
Coelom that is restricted to a cavity around the heart in adults
A
Eucoelomate
7
Q
True or False: Majority of mollusks are small
A
True
8
Q
How long can a large mollusks grow?
A
20m or to 900kg
9
Q
Anatomy and Physiology: Contains the feeding, sensory, and locomotor organs.
A
Head-foot
10
Q
Contains digestive, circulatory, respiratory, and reproductive organs. It is also found above the foot.
A
Visceral Mass
11
Q
True or False: Most mollusks have well-developed heads
A
true
12
Q
This contains the mouth and specialized sensory structures such as photoreceptors
A
Head
13
Q
True or False: Cephalopods have complex eyes
A
True
14
Q
Extendable tongue-like organ. Found in all mollusks except bivalves and most solenogasters
A
Radula
15
Q
has filelike teeth made of chitin for scraping, piercing, tearing, or cutting
A
The radula
16
Q
True or False: the teeth in radula are continuously replaced.
A
True
17
Q
These supports the radula
A
Odontophore
18
Q
True or False: foot is modified in some groups.
A
True
19
Q
Adapted for movement or attachment to surfaces, usually located on the ventral surface, and movement is typically waves of muscle contraction
A
Foot
20
Q
True or False: Foot is modified in some groups
A
True
21
Q
What is the foot for limpets?
A
Attachment disc
22
Q
What is the foot for bivalves
A
Hatchet foot
23
Q
What is the foot in cephalopods
A
Siphon
24
Q
Tissue that extends outward from the visceral mass, secretes the shell, contains sensory receptors, capelike; wraps around the body
A
Mantle
25
Space between the visceral mass and mantle. It also houses respiratory organs such as gills (ctenidia) and lungs. It is also where digestive, reproductive, excretory system products are emptied.
Mantle Cavity
26
In aquatic mollusks, water is pump continuously into the mantle cavitiy for?
Respiration, feeding, and excretion
27
They use the mantle and mantle cavity for jet propulsion
Cephalopods
28
True or False: *Many* mollusks can withdraw their head or foot into the **mantle cavity**
True
29
Secreted by mantle and has three layers
Shell
30
What are the three layers of a shell
Periostracum, Prismatic layer, and Nacreous layer
31
What is prismatic layer and nacreous layer made of?
Calcium Carbonate
32
What is periostracum made of?
Conchiolin
33
True of False: Mollusks shell are varied
True
34
True or False: Periostracum is thinner or absent in marine mollusks vs freshwater mollusks
True
35
Where does calcium for the shells come from?
Environment
36
Internal structures and Functions: Most mollusks have a ______ circulatory system
Closed Circulatory System
37
True or False: Open Circulatory system are generally less efficient at supplying oxygen
True
38
True or False: Digestive tract is complex and specialized (Extensive ciliary tracts)
True
39
Mollusks have **2 kidneys** called
Metanephridia
40
The inner end opens into the coelom by?
a nephrostome
41
True or false: **Kidney ducts** are also used in **discharging gametes**
True
42
True or False: **Most** Mollusks are **dioecious** while some are also hermaphroditic
True
43
True or false: Larvae are typically free-swimming **trochophore** larvae
True
44
Some groups such as
bivalves and gastropods
have an additional larval
stage called?
Veliger
45
Free-swimming, early foot, shell, and mantle are visible, only free-swimming stage in some mollusks
Veliger
46
True or False: Cephalopods, some bivalves, and
some freshwater and marine
snails have no free-swimming
larvae
True (Juveniles hatch directly
from eggs)
47
8 classes of mollusk:
○Caudofoveata
○ Solenogastres
○ Polyplacophora
○ Monoplacophora
○ Gastropoda
○ Cephalopoda
○ Bivalvia
○ Scaphopoda
48
Shell-less wormlike animals, Have an **oral shield and a radula**, **Dioecious**, **Resemble the likely common
ancestor of all mollusks**
Caudofoveata
49
Similar to caudofoveates, No radula or gills, Monoecious, Often feed on cnidarians
Solenogastres
50
“Many plates”, commonly known as chitons, dorsoventrally flattened,
dorsal shell is made up of 8 plates, Have a radula
Polyplacophora
51
**Chemoreceptive sense
organs** found near the **anus**
Osphradia
52
True or False: Polyplacophora is mostly dioecious and has no veliger stage
True
53
True or False: Head and cephalic sensory
organs are reduced
True ( Photosensitive structures
pierce through the plates)
54
“One plate”, One caplike shell covering the
dorsal side, Simple radula, Some organs are serially
repeated (Pseudometamerism)
Monoplacophora
55
“Boat feet”, also known as tusk shells or
tooth shells, mantle is tube shaped, single conical shell open on
both ends, Lack ctenidia
Scaphopoda
56
If Scaphopoda lack ctenida then how does gas exchange occur?
Gas exchange occurs
through the mantle
57
“Stomach foot”, the **largest class of mollusks**, includes **snails, slugs, conches,
limpets, sea butterflies**, **Only class with terrestrial
species**
Gastropoda
58
Gastropods are either?
shell-bearing or have a
reduced shell
59
True or False: *Most* gastropods have a
**head with eyes on
tentacles**
True
60
True or False: Gastropod's shell is always univalve when
present (one piece)
True
61
True or False: Shell gets **larger and spirals**
around **the central axis**
True
62
contains the
smallest and oldest whorl
The Apex
63
_____is often colored with an operculum
The Aperture
64
The aperture (opening) is
often colored with an
Operculum
65
The **rotation** of the shell, mantle, and visceral organs in **gastropod
development**. This also **allows the head to be
withdrawn into the
mantle cavity.**
Torsion
66
This leads to the anus and
mantle cavity opening
above the head (Increases risk of fouling)
Torsion
67
The spiral winding of the
shell and visceral mass
Coiling
68
True or False: **early gastropods** had a
**bilaterally symmetrical shell**
True
69
True or False: Evolving a **cone-shaped
shell** allowed for more
**compact body plans**
True
70
Why are organs asymmetrically arranged?
To account for the unbalanced
weight
71
What are lost in most extant species?
Right gill, atrium, and
kidney are lost in most
extant species
72
What is the advantage of losing the right gill?
It helps avoid fouling
73
True or False: Most gastropods are **herbivores**
True
74
True or False: *Some* feed on **decaying flesh**
while others **hunt**
True
75
**Venomous cone snails**
(genus Conus) have a
**modified radula** for
administering a **venom**
called
Conotoxin ( Lethal to humans in
several species)
76
Most gastropods respire using a?
Ctenidium
77
True or False: Basal gastropods have 2 ctenidium
True
78
**Pulmonates** have a **highly
vascular area in the mantle
cavity** that serves as a ______
Lung
79
True or False: In Gastropoda, sensory organs include **eyes or
simple photoreceptors, tactile organs, and chemoreceptors**
True
80
True or False: Gastropods can be monoecious or dioecious
True
81
True or False: in monoecious gastropods, both partners lay eggs
True
82
Three subclasses of Gastropod:
Prosobranchia, Opisthobranchia, Pulmonata
83
**Largest group**; *most* **marine
snails** and *some*
**terrestrial/freshwater
gastropods**. It only has one pair of tentacles
Prosobranchia
84
Sea slugs, sea hares, sea
butterflies. They are mostly marine and shallow water and have 2 pairs of tentacles
Opisthobranchia
85
**Land and most freshwater
snails/slugs** with a **few
brackish and marine
species**. This subclass has no ctenidia; **mantle cavity has a lung**
Pulmonata
86
“Two-valves", **2-part shelves** fused with
ligaments on the dorsal side and **opened and closed by muscle**
Bivalvia
87
Examples of this are Oysters, mussels, scallops,
clams, etc
Bivalves
88
True or False: Bivalves are **Mostly marine** with **some living in freshwater and brackish
environments**
True
89
True or False: Majority of Bivalves are **sedentary
filter-feeders**
True
90
True or False: Bivalves has No head, radula, and minimal
cephalization
True
91
True or False: Shell of a Bivalve is Laterally compressed
True
92
2 shells (valves) held
together by a
Dorsal hinge
ligament
93
Oldest part of the shell is
called the
Umbo
94
is a byproduct of a response to irritation caused by a foreign object
Pearl Production
95
True or False: Mantle secretes many
layers of nacre around
the object
True
96
Tue or False: Visceral mass suspended
from the dorsal side
True
97
True or False: *Posterior side of the mantle
folds* are **modified** to form **incurrent and excurrent
openings**
True
98
True or False: **Foot** is attached to the
*visceral mass*
**anteroventrally**
True
99
How is blood pumped?
Blood is pumped into
the foot to anchor it
into the substrate, then
muscles contract to
shorten the foot
100
How can file shells and scallops swim?
Scallops and file shells
can swim by **clapping**
their valves
101
Where does gas exchange occur in Bivalves?
Gas exchange occurs through the mantle and ctenidia
102
These are highly modified
for filter feeding
Ctenidia
103
True or False: **Respiratory currents** bring *water and food particles* into the
**mantle cavity**
True
104
True or False: **Some** bivalves have **symbiotic
relationships** with bacteria and
dinoflagellates
True
105
What do Shipworms produce to digest wood?
Shipworms have bacteria
that **produce cellulase** to allow them to digest wood
106
Where do Giant clams get nutrition?
Giant clams get nutrition from **photosynthetic
products of dinoflagellates**
107
True or False: Bivalves are usually dioecious
True
108
How are gametes discharged?
Gametes are discharged
into the mantle cavity then
carried out with excurrent
flow
109
True or False: Fertilization is external in most bivalves
True
110
Which clams have internal fertilization
most of freshwater clams
111
True or False: Many bivalves burrow into mud
or sand while some can burrow into wood
or stone
True
112
“Head foot” These are Octopuses, squid, cuttlefish,
nautilus. All are marine
Cephalopoda
113
True or False: Cephalopoda are active predators
True
114
What do Cephalopoda feed on?
They feed on small fish,
crustaceans, worms, and
other mollusks
115
How are their food captured?
Food is **captured with the
arms** and then brought to
the **beaklike jaws**
116
Where do octopuses and cuttlefishes secrete venom?
Octopuses and cuttlefishes
secrete venom from their
salivary glands
117
True or False: The blue-ringed octopus
produces a potent
**neurotoxic venom** that is
lethal to humans
True
118
Shell: the only
extant cephalopod with an
external shell
Nautilus
119
True or False: Shell of a nautilus is divided into
multiple internal
chambers.
True
120
True or False: The Chambers are filled
with **gas** to keep the
**shell upright**
True
121
True or False: The shell is small, curved,
and completely surrounded
by the **mantle** in **cuttlefish.**
True
122
In squids, internal shell is reduced into
Pen
123
This cephalopod completely lack shell
Octopus
124
Movement: Cephalopods move by
**expelling water** from
the **mantle cavity**
through a _____?
Siphon (Siphon can be aimed)
125
True or False: **Squids and cuttlefish**
are excellent swimmers
True
126
True or False: Octopuses are more
adapted for crawling
True
127
What kind of circulatory system do Cephalopods have?
Cephalopods have a
closed circulatory
system
128
True or false: Cephalopods have **2
branchial hearts** for
moving blood
through the gills and
**1 systemic heart** to
move blood to the
rest of the body
True
129
Function of 2 branchial hearts of Cephalopods
moving blood
through the gills
130
Function of the systemic heart of a cephalopods
To move blood to the
rest of the body
131
True or False: Cephalopods other
than nautiloids only
have one pair of gills.
True (Nautiloids have 2 pairs)
132
True of False: Cephalopods have complex
and elaborate nervous
systems and sensory organs
True
133
They have the largest brain in any
invertebrate with
multiple lobes
Cephalopods
134
The **nerve fibers** of
this aquatic animal are among the
**largest in any animal**
Squids
135
True or False: Cephalopods have sensory organs that are well-developed
True
136
The eyes of cephalopods are highly complex except for?
Nautiloids
137
True or False: Cephalopods can be
taught to distinguish
shapes
True
138
True or False: Arms have both tactile
and chemoreceptor
organs
True
139
They are capable of
observational learning and
tactile exploration
Octopods
140
True or False: An octopus observing
another being rewarded
would remember which
choice is rewarded
True
141
True or False: Octopods can distinguish
textures via touch
True
142
How do cephalopods communicate?
Cephalopods communicate
primarily through visual
signals
143
Color changing of Cephalopods is facilitated
by cells
Chromatophores
144
True or False: Most cephalopods
cannot detect color;
patterns are detected as
polarized light
True
145
Why do cephalopods produce black ink?
Cephalopods produce a dark ink
for defense
146
True or False: **All cephalopods** are
dioecious
True
147
How do Cephalopods reproduce?
Males use a modified arm to pluck a spermatophore
from the mantle cavity and insert it into a female’s
mantle cavity
148
Why do males engage in color display during reproduction?
Males engage in color
displays to compete
prior to copulation
149
Why do cephalopods not produce free-swimming larvae?
because Juveniles hatch directly from eggs
150
3 subclasses of Cephalopods:
Nautiloidea, Ammonoidea, Coleoidea
151
Genus Nautilus is the only surviving member of this cephalopod and have 2 pairs of gills
Nautiloidea
152
Ammonites; all extinct
after the Cretaceous
Ammonoidea
153
All other living
cephalopods and only has 1 pair of gills
Coleoidea
154
True or False: Mollusks are an important food source
True (60 million tonnes of
mollusks were harvested
from the eastern US in 2014
amounting to 2.68 billion
USD)
155
They are threatened by ocean acidification
Mollusks
156
How are mollusks affected by ocean acidification
Higher levels of acidity
affect the availability of
calcium and Shelled mollusks are
vulnerable to increases in
acidity.
