Download Phylum Mollusca

Current Failures: 1130/2012
1st:
100023457 (44) (57)
100023003 (54) (87)
100023579 (41) (62)
100028564 (39) (58)
100023842 (49) (76)
100023643 (52) (74)
2nd:
100023258 (58) (70)
100037316 (51) (87)
100022959 (48) (85)
100038234 (21) (83)
3rd:
100022683 (62) (81)
100023368 (57) (74)
100023439 (62) (76)
5th:
100023724 (38) (83)
100023306 (59) (80)
100023606 (59) (83)
100037899 (48) (76/I)
100022851 (66) (84)
100036042 (64) (78)
4th:
100038241 (45) (63)
100023553 (34) (72)
100011730 (3) (66)
Yellow # = 1st & 2nd 6-weeks Average
Italicized = At risk of failing the semester
7th:
100033796 (63) (79)
100034582 (58) (78)
100023847 (64) (70)
Bellwork – Bellwork 12/03/2012
1. What is a “water vascular system?”
2. In which phylum can this system be found?
3. When considering vision, how is it different from echinoderms, to
arthropods, to mollusk?
Bellwork – Bellwork 12/03/2012
Name the sections & functions of a crustacean:
Bellwork – Bellwork 11/20/2012
• Don’t start changing water until you are told to do so.
• I will begin to dock you & your group points if vials are not cleaned
out or if the lids of the water jugs are left off. Also, the water jugs
need to be placed back in the shelves where you got them, not simply
piled in the corner.
• Keep in mind that I am paying attention to who does/does not help out
their group
• When you refill your tanks, make sure to fill the tank up to the
waterline unless you have been told to do otherwise.
Bellwork – Bellwork 11/27/2012
1) When considering mollusks, what does HAM stand for?
2) What are the three main parts of HAM? What is the
function of each?
Bellwork –11/28/2012
1) Do not start working on your lab or water changes just yet!
2) Using anterior, posterior, dorsal and ventral, label the following:
a)
b)
c)
d)
e)
f)
g)
Telson (crustacean)
Antenna (crustacean)
Mandible (crustacean)
Walking legs (crustacean)
Swimmerets (crustacean)
Nerve cord (mollusk)
Nerve cord (crustacean)
3) Where is a nacreous layer found? Why is it important to a mollusk
such as a conch?
Bellwork –11/28/2012
1) If you are finished or close to finished with your
lab, you should be the one from your group
working on the tank.
2) Make sure to complete any additional instructions
that are written on your tank.
3) You lab must be completed by the end of class,
remember no groups larger than 4
Crustacean Lab:
14) When considering arthropods, crustaceans
especially, and echinoderms: These two phyla split in
their evolutionary paths based on what physiological
difference?
Replace question #9 with:
• What is the main function for each appendage of a crustacean:
a) Mandibles
b) Antenna
c) Walking Legs
d) Swimmerets
e) Telson
Bellwork: 11/29/2012
1) Define decapod:
2) Give an example of a crustacean that is not a
decapod (sessile).
Crustacean Lab: Unique Features
1. Brine shrimp
2. Decorator Crab
3. Banded coral shrimp
4. Sally Lightfoot Crab
5. Hermit Crab
6. Peppermint Shrimp
7. Bamboo shrimp
8. Skunk Cleaner Shrimp
9. Camel Shrimp
10. Arrow Crab
11. Pistol Shrimp, clip 2
Crustacean Lab: Questions
1. Which section(s) of the body would be most vulnerable to a
predatory attack? Why do you think this?
2. What is unique about the shape eyes of crustaceans in comparison to
the other organisms that we have studied?
3. Describe 3 differences between organisms labeled as shrimp and
those labeled as crabs.
4. What one advantage and disadvantage of the crustacean eye being on
long stalks?
5. The tiny brine shrimp you investigated fill a very similar niche as
krill. What type of role does these organisms play within ocean
ecosystems?
6. Name three crustacean body parts that are used for the detection &
consumption of food.
7. When are crustaceans most vulnerable?
Crustacean Lab: Questions
8. Why must they go through this vulnerable process?
9. What is the main function for each appendage of a crustacean:
a) Mandibles
b) Antenna
c) Walking Legs
d) Swimmerets
e) Telson
10. Define decapod.
11. Name an example of a crustacean that is not a decapod (which one is
sessile)?
12. What type of circulatory system can be found in crustaceans?
Describe how this system works.
Crustacean Lab: Questions
13. Many of the walking legs and claws of crustaceans are covered in
small hairs. What are these hairs called & what are they used for?
14. When considering arthropods, crustaceans especially, and
echinoderms: These two phyla split in their evolutionary paths based
on what physiological difference?
15. What is the hypothetical ancestral mollusk?
16. Why is this organism considered “hypothetical?” What body
feature(s) of mollusks makes this the case?
17. Where can the mantle be found within a mollusk?
18. What is the main function of the mantle?
19. Why is it that a sea star can pull open a mollusk such as an oyster or
a clam, where as a serpent or brittle sea star cannot do anything
requiring such strength?
Crustacean Lab: Questions
20.What do each of the following translate into:
a) Arthropod
b) Gastropod
c) Cephalopod
d) Bivalve
Bellwork: 11/20/2012
Collect the following data:
Salt Water Tanks Only:
• DO
- Phosphate
• Turbidity
- Salinity
• Nitrate
- Calcium
• Nitrite
- Water Hardness
• Ammonia
Make sure to clean out any excess food
• pH
from your filter and gravel/sand. Scrub off
the inside of the glass & clean the outside
• temperature
with Windex once you are finished.
•
Body Part
Antennae
Antennules
Maxillae &
Mandibles
Walking Legs
Abdomen and
Telson
Swimmerets
Feeding
Walking
Swimming
Escaping
Questions:
1) How does the exoskeleton of an arthropod compare with
that of the endoskeleton of an echinoderm? What is each
made of?
2) Which appendages are attached to the cephalothorax?
Which are attached to the abdomen?
3) Which segment of the body is most flexible?
4) How does the nerve cord of an arthropod compare with that
of a human?
5) Arthropods are the first organisms that we have talked
about that have a rounded eye. What do you think this will
change about the visual information collected by this organ
in comparison to eye spots from simpler organisms?
Questions:
6) Do crustaceans have defined genders? How can you tell
one from another?
7) What are three biologically new features about crustaceans
(ones that haven’t been present in previously discussed
organisms).
8) Humans have a closed circulatory system. What type of
circulatory system do crustaceans have? Describe how this
system works.
9) Are crustaceans nektonic, planktonic, or benthic? What
type of consumer are they (herbivore, carnivore, etc)?
10)Crustaceans are found within which phylum? What does
the phylum name translate to? Give an example of a
crustacean that lives on land.
Limb Functions
Anatomy
Phylum Mollusca
Introduction
• Includes animals such as squids, snails, oysters, clams and slugs.
• Most are marine, but many are freshwater and some live on the
land
• Despite the diversity of form and function among the molluscs, all
members of this group have the same basic body plan.
• This is often indicated by presenting a hypothetical ancestral
mollusc (HAM)
• HAM is hypothetical primitive ancestor that has characteristics that
appear among most members of the mollusca
A Closer look at HAM
The foot - a broad, flat muscular organ that is adapted for
locomotion and attachment
The visceral mass - contains the internal organs
The mantle - a fold of tissue that drapes over the visceral mass;
space between the mantle and the visceral mass is called the mantle
cavity
The Shell
• The mantle is responsible for secreting the shell.
• The shell is comprised of three layers:
• The outside of the shell is covered by an organic layer periostracum
• The middle prismatic layer is characterized by densely packed
prisms of calcium carbonate laid down in a protein matrix
• The inner nacreous layer
is composed of calcium
carbonate sheets laid down
over a thin layer of protein
Gills
• The gills of HAM are often indicated as one or more pairs of
bipectinate gills, - flattened filaments attached to a
longitudinal axis on either side
The Radula
• The mouth cavity of HAM possesses a specialized rasping organ called
the radula; sits on a cartilaginous structure - odontophore
• Particles of food brought into the mouth are bound in mucous secreted
by the salivary glands
Body Plan of
Mollusks
29
Other Features of HAM
• Nervous system consists of a nerve ring and 2 longitudinal nerve
cords
• Coelom is reduced
• Open circulatory system
• The excretory
organs of the
molluscs are
metanephridia;
inner ends open into
the coelom via a
ciliated funnel called
the nephrostome;
wastes leave the body
via the
nephridiopore
Molluscan Diversity
Class Gastropoda
• Three evolutionary innovations occurred among the gastropods:
changes in the shell, increased development of the head, the
embryonic process of torsion
1. Changes in the Shell
• The shell became higher and
conical with a reduced aperture
• The shell also became coiled
• Shells initially were planospiral
- bilaterally symmetrical shell
with the whorls lying in the same
plane
• Modern day shells are
asymmetrical - each successive
coil is a little outside and offset a
little above the one below
Why was there a change in shell
architecture?
• Planospiral shell was not as
compact as the asymmetrical shell
• But, this change in symmetry of
the shell created a shift in the
weight to one side of the animal
• To achieve a better weight
distribution, the shell needed to
shift upward and posterior
• The shell axis then became
oblique to the longitudinal axis of
the foot (= bilateral asymmetry)
• The weight and bulk of the main
body whorl, pressed on the right
side of the mantle cavity; thus,
many of the organs on the right
side became lost during evolution
2. The Increased Development of the Head
• The head bears 2 pairs of tentacles, with the eyespots at the base of
one pair
eyespots
tentacles
3. The Embryonic Process known as Torsion
During embryonic development, 1 side of the visceral mass grows at
a much faster rate than the other.
• Causes the visceral mass to rotate 180 degrees relative to the headfoot.
• Advantages: head retracted first; gills receive water currents; the
osphradium (olfactory organ associated with respiratory organs) is
now directed anteriorly
• Disadvantage: may cause fouling
Mollusks
• Mollusks (cont.)
– Nervous system consists of several ganglia
connected by nerve cords
– Coelom (absorbs shock) is reduced, and largely
limited to the region around the heart
– Heart pumps hemolymph through vessels into
hemocoel
36
Adaptations to Avoid
Fouling
• Improved separation of
inhalent and exhalent water
flow
• In some of the more primitive
gastropods (keyhole limpets),
the shell contains a hole at the
top through which the exhalent
water stream exits
• In the more advanced
gastropods, water is brought
into the mantle cavity on the
left side, passes over a single
gill, and exits the right side
Shell
• Most have a single,
spiraled shell and can
move the entire head
and foot into this
shell for protection.
• Also, many
gastropods have a
hardened plate called
the operculum on
the back of the foot
that plugs the shell
aperture when the
body is withdrawn
Bellwork: 12/04/2012
Label: spire, aperture, whorls, sutures, body whorl, anterior, posterior
Nutrition
• Many gastropods are herbivores and use their radula scrap algae
from surfaces of rocks
• Some gastropods are active predators and in these the radula is often
highly modified, e.g., as a drill (oyster drills) or harpoon (venomous
gastropods)
Cone snail
Respiration
• Aquatic gastropods possess gills for respiration
• Terrestrial gastropods obtain oxygen via a well vascularized
mantle
Vascularized
mantle
gills
Bivalves
• Clams, oysters, mussels, and scallops
• Shell of two hinged parts, closed by powerful
muscles
• No head, no radula
• Circulatory system open
• Sexes are separate
• Ciliated gills hang down within mantle cavity on
either side of visceral mass
Beating of cilia causes water to enter cavity
Filter Feeders – capture tiny food particles
suspended in water
Bivalve
Diversity
44
Class Bivalvia
• Shells divided into 2 equal halves or
valves
• Mantle tissue is indented in the anteriorposterior margins, with 2 centers of
calcification
• Shells joined at the dorsal midline by a
non calcified protein ligaments called the
hinge
• Muscles fused across the width (from left
to right) at 1 anterior and posterior position
and form adductor muscles; connect the 2
shell across their width; close the shell
Gills as filters
• Gills play an important role in
feeding: of the total volume of
water that is processed by gills
only 5% is required for gaseous
exchange; 95% of the volume is
used to supply the animal with
food
Adaptive Radiation of Bivalves
Soft Bottom Burrowers
• Those that live deep in the sand or mud; burrowing is accomplished
using the foot that is extended through a specific part of the shell - the
pedal gap
• These molluscs have long tubular extensions of the mantle called
siphons, with both inhalent and exhalent opening
Attached Surface Dwellers
• Those that live attached to hard surfaces
• Some (i.e. oysters) lie on their side and have one of the shell fused
or cemented to the substrate; foot is absent
• The common mussels attach to the substrate by means of byssal
threads, secreted by glands in the foot; foot is reduce in the organisms
Adaptive Radiation of Bivalves con’t
Unattached Surface Dwellers
• Rest unattached on the substrate
• Capable of limited locomotion by rapid clapping of their valves
using a powerful adductor muscle; forces a jet of water out of the
mantle cavity
Hard Bottom Burrowers
• Several species of bivalves are capable of burrowing into hard
surfaces such as rock, coral, wood
• Use the anterior margins of their shell to chip away at the rock;
some secrete chemical to breakdown rock
Adaptive Radiation of Bivalves
Cephalopods
• Large head attached to tentacles with
suction cups or hooks
• Most lack shell (except nautilus)
• Most intelligent of all invertebrates
Cephalopods
• Squid, octopus, cuttlefish, nautilus
• Differs from other mollusks in their appearance and
specializations for life as active carnivores
– Active swimmers (can catch fish)
– Very responsive to stimuli
– All but nautilus have an ink sac used to confuse predators
– Body can change color in response to stimuli through use
of Chromatophores
– Have an extremely well-developed eye
Feeding
• Cephalopods are carnivores
• Have a powerful parrot like beak that is used to tear prey apart.
• They also have a powerful radula
• In some of the octopuses the salivary glands are modified poison
glands
Locomotion
•
Cephalopods are excellent swimmers: streamlined body;
tentacles and fins as stabilizers
• Swim by means of jet propulsion, using the highly modified
muscular mantle and the siphon
– By relaxing the mantle the mantle cavity is expanded and water can be
drawn in
– By contracting the mantle water can be forced out of the mantle cavity by
means of the small siphonal opening
Shell
• Primitively the cephalopods possessed a shell; the fossil record
indicates both coiled and non-coiled shells
• Extant members with coiled shells include Nautilus
• Some cephalopods (cuttlefishes) have an internal shell - cuddle bone
•The octopods have lost the shell entirely
Other General Features
• For protection, they possess an ink
sacs
• Cephalopods have well-developed
sense organs, including a camera type
eye
• Some have well-developed brains and
show a remarkable capacity for
learning.
• Cephalopods are the only molluscan
class with a closed circulatory system
Reproduction
• Sexes are separate
• Sperm is transferred to females in packets - spermatophores
• Male uses a tentacle to reach into its mantle cavity and pick
up some spermatophores
• It then inserts the tentacle into the mantle cavity of the female
near or within the oviduct
Examples of Cephalopods
• Close-up view of an unknown species
of bathypelagic squid encountered by
ROV Tiburon at 3,380 meters depth off
the coast of Oahu.
• This animal was estimated to be four
to five meters in length.
• Different from other squids in that
their eight arms and two tentacles are
roughly equal in length and thickness.
• A giant squid (3.15-metre-long) has
netted off the UK coast; first time in
15 years.
• The squid, believed to be female and
three years old, did not survive being
brought to the surface.
The Mimic Octopus
An Indonesian octopus
mimicking a flatfish (above) and
a lionfish (right)
The Mimic Octopus
Bellwork: 12/05/2012
• Sign in for a quiz
• Please pick up a notecard and fill in the following
information:
– What have you enjoyed about this class so far/What am I doing
correctly as a teacher?
– What could have been done better? What could I be doing to be a
better teacher? What could I do to improve the subject matter that
you are being taught?
• If you do not care, or have no opinion, please leave the card
blank.
• You do not need to put your name on the card, its not for a
grade
Mollusk Observation Lab: Instructions
• Groups may be NO LARGER than 4
• You must work together as a group, there will be
plenty of time to get everything finished
• Station #9 will be a separate grade
Mollusk Observation Lab:
Station #1:
1. Sketch the radula on the slide
a)
b)
c)
d)
What phylum has this tissue?
What is this tissue used for?
Where can this tissue be found within the organism?
What has this tissue been replaced by in more advanced
organisms (mammals, reptiles, amphibians, fish, etc)?
Mollusk Observation Lab:
Station #2:
a) Sketch each shell and label the following:
a)
b)
c)
d)
e)
f)
Columella
Spire
Sutures
Body whorl
Anterior
Posterior
b) Why is each whorl the same shape?
c) What tissue fills the small space in the posterior
region of the shell when the organism is alive?
Mollusk Observation Lab:
Station #3:
1) Gently remove a sample from the jar
a) Sketch what you can see within the organism as well as the
connective tissue that holds the organism together.
2) Gently pull on the outer edges of the shell.
a) Does the shell easily open?
b) Which muscles hold this organism together?
c) How do organisms such as sea stars, equally as small, manage to
open these bivalves?
d) What features are lacking in bivalves that can be found in most
other mollusks?
Mollusk Observation Lab:
Station #4:
1) Observe both sides of the operculum under the dissection
microscope.
a)
b)
c)
d)
Sketch both sides & label the texture of each
Which side is held within the organism? Why do you think this?
What is the purpose of the operculum?
Sketch a snail when it is out of its shell. Label where the
operculum is found
2) Gently flip the snail over under the dissection
microscope.
a) Observe and sketch the snail as it opens up.
b) Label: mouth, radula, foot, eyes, antenna
c) How does it flip itself over?
Mollusk Observation Lab:
Station #5:
1)Sketch the dorsal and ventral views of this organism (do not
flip over the organism to view the ventral side).
a) How is this snail different than other snails observed (if none
have been observed yet, Google an image of “snail”)
b) Label: foot, eye, tentacle, and mantle
c) Specifically, what protective feature is this organism lacking that
is found in most snails?
d) Why does it not need this tissue?
Mollusk Observation Lab:
Station #6:
1) Sketch the two cephalopods & label each as: nautilus, squid,
cuttlefish, octopus
2) Label the following:
a)
b)
c)
d)
e)
f)
Arm
Tentacle
Suction cup
Eye
Mantle
Beak
3) Answer the following:
a)
b)
c)
What type of circulatory system do these organisms have?
What are chromatophores? Name two reasons they are used by cephalopods
What is one major difference (physiological, not size) between the two
samples at this station?
Mollusk Observation Lab:
Station #7:
1)Observe both of these snails while they are upright & sketch them as
they move through their container.
a)
b)
c)
Label: shell, eye, foot, radula, unique feature of each
Which of these organisms hides under the sand? Why do you think this?
Describe and hypothesize a reason for the pattern on the bumblebee snail
2)Flip the organisms onto their “back” at the same time.
a)
b)
Describe how does each flip itself over.
Which flips itself over faster?
3)Observe each organism on its back under the dissection microscope.
a)
Label the foot and radula of each
Mollusk Observation Lab:
Station #8:
1) Observe both the small & large conch shells
a)
b)
How many whorls are on each
Sketch one of the shells and label: anterior, posterior, aperture, spire, sutures,
body whorl
2) Observe the living conch.
a)
b)
c)
d)
What feature(s) of the shell is associated with the eyes and tentacles of the
organism?
Using the large shell, how many times does this feature appear?
Where can the nacreous layer be found on these shells?
What is the purpose of the nacreous layer?
3) Flip over the conch & observe how it flips itself back over.
a)
From this observation: what feature is different in conch than in other
gastropods/snails?
Mollusk Observation Lab:
Station #9:
1) Sketch each shell
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
Label: anterior, posterior, aperture, spire
Name a unique feature of each
How many whorls does each have?
Once the organisms within each shell has died, what are many of these shells
used for?
What is a coelom?
Why would an intertidal organism like snails benefit from a coelom?
What are the two functions of gills within a gastropod?
How is the shell/mantle different in: gastropods, cephalopods, bivalves, and
HAM?
What is HAM, why is it considered hypothetical?
Describe the differences in the eyes/eyespots in: echinoderms, crustaceans,
gastropods, and cephalopods.
Name and describe the 3 evolutionary innovations found in gastropods
Bellwork: 12/06/2012
1. Give 3 examples of an echinoderm:
2. Name a crustacean that spends its entire life on land:
3. Define decapod:
4. Name an crustacean that is NOT a decapod:
Current Failures:
1st:
100023457 (39)
100023579 (41)
100023842 (47)
100023643 (51)
3rd:
100022683 (62)
100023368 (54)
100023439 (57)
100036042 (62)
2nd:
100023258 (53)
100037316 (48)
100038234 (23)
4th:
100038241 (46)
100023553 (42)
100011730 (53)
5th:
100023306 (56)
100023606 (59)
7th:
100033796 (61)
100038593 (67)
100023847 (66)
Bellwork: 12/07/2012
e) What is a coelom?
f) Why would an intertidal organism like snails benefit
from a coelom?
g) What are the two functions of gills within a gastropod?
h) How is the shell/mantle different in: gastropods,
cephalopods, bivalves, and HAM?
i) What is HAM, why is it considered hypothetical?
j) Describe the differences in the eyes/eyespots in:
echinoderms, crustaceans, gastropods, and cephalopods.
k) Name and describe the 3 evolutionary innovations
found in gastropods
Bellwork: 12/07/2012
e) What is a coelom?
f) Why would an intertidal organism like snails benefit
from a coelom?
g) What are the two functions of gills within a gastropod?
h) How is the shell/mantle different in: gastropods,
cephalopods, bivalves, and HAM?
i) What is HAM, why is it considered hypothetical?
j) Describe the differences in the eyes/eyespots in:
echinoderms, crustaceans, gastropods, and cephalopods.
k) Name and describe the 3 evolutionary innovations
found in gastropods
Bellwork: 12/07/2012
Collect the following data:
Salt Water Tanks Only:
• DO
- Phosphate
• Turbidity
- Salinity
• Nitrate
- Calcium
• Nitrite
- Water Hardness
• Ammonia
Make sure to clean out any excess food
• pH
from your filter and gravel/sand. Scrub off
the inside of the glass & clean the outside
• temperature
with Windex once you are finished.
•