Lecture 7 Flashcards
(78 cards)
1
Q
what kind of symmetry do mollusks have
A
bilateral
2
Q
based on the germ layers of mollusca, how would you define them
A
triploblastic coelomates
3
Q
what is a coelomate
A
a true coelom lined with peritoneum derived from mesoderm
4
Q
what is a coelom?
A
the fluid filled cavity of an animal that contains the internal organs
5
Q
what is the habitat of gastropoda
A
- aquatic
- terrestrial
- semi terrestrial
5
Q
what are the classes of the phylum mollusca
A
- polyplacophora
- gastropoda
- bivalvia
- cephalopoda
5
Q
what is the habitat of polyplacophora
A
- aquatic
- semi terrestrial
6
Q
what is the habitat of bivalvia
A
aquatic
7
Q
what kind of shell is on polyplacophora
A
dorsal plates
8
Q
what is the habitat of cephalopoda
A
aquatic
9
Q
what kind of shell is on gastropoda
A
coiled
9
Q
what kind of shell is on bivalvia
A
pair of lateral plates
10
Q
what kind of shell is on cephalopoda
A
present, reduced, or absent
11
Q
are there feet on polyplacophora
A
yes
12
Q
are there feet on gastropoda
A
yes
13
Q
are there feet on bivalvia
A
yes
14
Q
are there feet on cephalopoda
A
they are modified into “arms”
14
Q
what are the key defining characteristics of a mollusc
A
- a mantle
- a radula
- a foot
15
Q
on molluscs, what is a mantle
A
specialized tissue formed from the dorsal epithelium that secretes a shell or multiple shells
16
Q
on molluscs, what is a radula
A
an organ with teeth used for feeding
17
Q
on molluscs, what is a foot
A
a ventral structure used for attachment or locomotion
18
Q
a simple mollusc body has …
A
- foot or head/foot
- visceral mass
- shell
19
Q
what structure assists mollusc feeding
A
the radula
19
Q
what can a radula do if it is modified
A
can be used as a harpoon to inject venom into prey
20
what kind of digestion occurs in the stomach of molluscs
20
in molluscs, digestive enzymes are secreted by what
salivary glands and dgestive glands
20
in molluscs, the anus empties into where
the mantle chamber
20
all animals rely on _______ ________ to produce energy
mitochondrial respiration
21
mitochondrial respiration produces energy in what form
ATP
22
what does mitochondrial respiration require
oxygen
23
what does mitochondrial respiration produce
carbon dioxide
23
what are the four steps of gas exchange
1. ventilation
2. gas exchange (diffusion)
3. circulation (perfusion)
4. cellular respiration (diffusion)
24
what are the key qualities of diffusion
- very efficient over short distances
- time needed increases exponentially with distance
- time required for diffusion quickly becomes a barrier to body size
25
what is bulk flow
a process that allows for transport of substances faster than would be possible by diffusion alone
25
where does bulk flow of water occur
in large animals that lack a circulatory system
25
what are ctenidia
gills
specialized respiratory organs used to obtain oxygen
26
how do molluscs perform ventilation
bulk flow of water over ctenidia
27
where does bulk flow of body fluids occur
animals that have a circulatory system
27
what is a closed circulatory system
circulating fluid remains contained in vessels throughout circulation
28
what fluids are in a closed circulatory system
blood
lymph
29
where is lymph found
closed circulatory systems of vertebrates only
30
what is an open circulatory system
circulating fluid enters open sinuses, allowing direct contact with tissues
31
what fluids are in an open circulatory system
hemolymph
31
what kind of circulatory system do molluscs have
most have open circulatory system
32
what kind of circulatory system do cephalopods have
closed circulatory system
33
how many hearts do cephalopods have
3
34
how does the body plan of a polypacophore differ from the typical mollusc
the mantle pushes out past the shell
35
how many plates does a polyplacophore have
typically 8
35
how does the body plan of a gastropod differ from the typical mollusc
the anus and mouth are at the same end
36
what is a synapomorphy
37
what synapomorphy occurs in all gastropods
rotation of the shell and viscera during development
37
how does the rotation of the shell and viscera occur in gastropods
brings the anus from the posterior end to the right side of the body, then all the way to the adult position above the head
counterclockwise
38
the synapomorphy of gastropods can lead to what
fouling
38
what is gastropod detorsion
a secondary reversal of torsion during development, such that anus is posterior rather than anterior
38
what is fouling
waste washing over the gills
pooping on their gills
39
in bivalvia, what holds the two shells together
a hinge ligament
40
when the adductor muscles are relaxed in bivalves, is the shell open or closed
open
40
what pulls the shells closed in bivalves
adductor muscles
41
when the adductor muscles are contracted in bivalves, is the shell open or closed
closed
42
most bivalves are what kind of feeders
suspension feeders
42
how does the body plan of a bivalve differ from the typical mollusc
no radula and no head
43
what does it mean to be a suspension feeder
43
bivalve gills are covered in what
cilia
44
what do the cilia on bivalve gills do
collect suspended organic matter and direct the food to the mouth
44
glands on the gills of bivalves secrete what and why
mucous that traps particles
45
in the class cephalopoda of molluscs, how has the foot been modified
modified into arms
46
what class of molluscs can perform camouflage
chephalopods
46
what is the difference between hologous traits and analogous traits
homologous means they have a shared common ancestor and descend from the same thing.
analogous means they have the same function but different origins.
47
what htings do cephalopods change for camouflage
- skin texture
- skin pigmentation
48
when papillae under the skin of cephalopods are extended, which muscles are relaxed and contracted
- erector contracted around papillae
- retractor relaxed coming out of papillae
49
how does a cephalopod change its skin texture
- papillae (skin protrusions)
- musculature under skin
- erector and retractor muscles control papillae
50
what fibres innervate the muscles around the chromatophore
nerve fibres
50
how do cephalopods change their skin pigmentation for camouflage
chromatophores
50
what are chromatophores in cephalopods
pigment containing cell with yellow, red, brown or black pigment granules
50
when papillae under the skin of cephalopods are retracted, which muscles are relaxed and contracted
- erector relaxed around papillae
- retractor contracted coming out of papillae
51
what fibres are arranged around the chromatophore
muscle fibres
51
when more of the chromatophore pigment in a cephalopod is visible, are the radial muscled relaxed or contracted
contracted
51
do cephalopods have a nervous system
yes!
