Honors Marine BiologyModule 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. Mollusca:
2. Arthropoda
3. Echinodermata
4. 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. Radulab. Gillsc. Excretroy organd. Tentaclese. 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 siphonsTo suck in and expel seawater.
Tiny cilia on the gillsBeat back and forth,Creating a current thatPulls in the water so thatPlankton and food particlesCan be trapped by the gillsAnd 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
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
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:
