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Honors Marine Biology
Module 5 – Marine Invertebrates II
October 21, 2014
Class Challenge
Your best impersonation
Quiz
Define and give an example for the
following:
mutualism,
commensalism,
parasitism.
Mutualism: A relationship between two or
more organisms of different species where
both benefit from the association.
A bee and a flower
Commensalism:
A relationship between
two or more organisms
of different species
where one benefits and
the other is neither
harmed nor benefited.
Barnacles on the fin of a whale
Parasitism: A relationship between two or
more organisms of different species where
one benefits and the other is harmed.
A tick, mosquito or a tapeworm on an animal
Homeschool Days at Mote Marine
See the October 6, 2014
wavemakersrq.wordpress.com
post that has the schedule.
Marine Invertebrates
Four Major Phyla:
1.
2.
3.
4.
Mollusca:
Arthropoda
Echinodermata
Chordata
Phylum Mollusca
And commonly called Mollusks, and
represent the most species in the ocean
than any other group.
They include clams, abalone, cone shells,
squid and octopuses.
Most mollusks have a bilaterally symmetric
soft body protected by a shell made of
calcium carbonate.
The shell provides protection from the
elements and predators and can also
provide body support.
Mantle
The soft body is covered by a mantle, which
is a sheath of tissue surrounding the
organs of a mollusk, producing the
mollusk’s shell and preforming respiration.
Foot
Many mollusks use a large, muscular foot
for locomotion, anchoring, or obtaining
food.
They also have a series of sensory organs
near their heads.
Gills
Are used for exchanging gases with the
surrounding water. Mollusks also have a
digestive tract, and a somewhat complex
nervous system.
A special organ allows these organisms to
scrape food into their mouths is called a
radula. It is covered with hundreds of
small teeth, used for scraping food into the
mouth.
Class Gastropod (Figure 5.1)
The head of a gastropoda is very complex
compared to that of most other mollusks.
Many of the species have eyes on the tips of
their tentacles. Gastropods have several
feeding strategies. Some have radula to
scrape algae off rocks, like the limpet and
abalones.
Nudibranch
• Have no shells. The name “nudibranch”
literally means “naked gills”. They are
some of the most colorful in the ocean
On Your Own questions
5.1 For each of the gastropod structures
listed below, indicate the organ in the
human body that would perform a similar
function:
a. Radula
b. Gills
c. Excretroy organ
d. Tentacles
e. Shell
Bivalves (Figure 5.3)
•
•
•
•
Mussels
Clam
Scallop
Oysters
• Bivalves have a hinged, two-piece shell.
All bivalves lack radulas and do not have a
noticeable head.
Bivalves have large and elaborate gills used not
only for gas exchange but also for filtering food
particles from the water.
They extend siphons
To suck in and expel
seawater.
Tiny cilia on the gills
Beat back and forth,
Creating a current that
Pulls in the water so that
Plankton and food particles
Can be trapped by the gills
And swept in to the mouth.
Bilvalves
Some burrow into the sand with their
muscular foot. Others have a strong
filaments called byssal threads that attach
themselves to rocks. Oysters cement
themselves to hard surfaces or each other.
Experiment 5.A: Bivalve/Shell
Observation
ID the Shell
Drawing
Killer Cone Snail
http://youtu.be/zcBmMPJrrKk
Gastropod attacks a bivalve
http://youtu.be/70OHQJ2SbQU
Class Cephalopoda
Is the most complex of the mollusks.
“Cephal” means head
“pod” means foot
This is very descriptive of this “head-footed” group of
animals.
Squid, octopus, cuttlefish and nautilus.
(see Figure 5.5)
Cephalopods
Have complex eyes that include a retina,
cornea, iris and lens.
They also have a brain that coordinates and
stores information.
Cephalopod’s
Body is protected by a muscular mantle enclosing
its gills. In other mollusks, water is taken into
the mantle cavity, moves over the gills, and is
slowly expelled through the siphon.
Cephalopods do not have an external shell, so
they can forcefully contract their mantle cavity,
shooting out a jet of water, which propels them
backward. In a squid or octopus, the siphon can
be turned in any direction to give them the ability
to move in any direction they choose.
In addition to the siphon, cephalopds have
sacs from which they can release a dark
fluid to confuse their enemies and allow
retreat.
What was this fluid once used for?
Labs
Experiment 5.B: Dissection of the Squid
Experiment 5.C: Dissection of the Clam
Clam Dissection
http://youtu.be/C-3GqvLswc8
Squid Dissection
•
http://youtu.be/OueQ9kU36i0
Homework
• Module 5 Pages 107 – 124
• Answer On Your Own Questions 5.1 to 5.6
• Study Guide Questions: define: a-e and
2-9.
• Finish Lab book – Bivalves and Univalves; Squid
Dissection.
• Quiz: know the squid dissection and be able to
label its parts.
• Class Challenge: