Incredible Suckers
Targeted grades: 6 – 8Developed by Tedd Davis and Sarah Olson
OVERVIEW
These lessons are part of a larger unit on the Mollusca. The video "Incredible Suckers" introduces students to the cephalopods and they move to hands-on labs with preserved and fresh cephalopods and work with a cephalopod web site.
Time: three to five 45-minute class periods.
VIDEO
"Incredible Suckers" (1985)
LEARNING OBJECTIVES
Students will be able to identify and compare species of Cephalopods. Students will have hands-on knowledge of live and preserved specimens and will know how to access and use a Squid-centered web site.
VIEWING ACTIVITIES
Prerequisite Knowledge: Students should have a grasp of the concept of biodiversity.
Focus for Viewing--ask students to look, listen and take notes on the following: characteristic(s) that all Cephalopods have in common; and (2) the main species of Cephalopods. Tell students that they will be watching a video during the class, but that it will be fast-forwarded and paused frequently for note-taking and discussion.
NOTE: Time codes on VCRs vary--the following pause points are approximate.
START the video at the opening credits. PAUSE at (1.07) and ask, "What is an abyss?"
START and then PAUSE at (3.13) and ask, "What is extinction ? Give examples."
START and PAUSE at (3.42). Ask, "What is the feature and characteristic that all Cephalopods have in common?" Also ask students to describe a Nautilus.
START and PAUSE at (7.00) and ask, "Why are all cuttlefish more advanced than the nautilus?"
START and PAUSE at (7.08) and ask the following questions: What are chromatophores? This Cephalopod has thousands of chromatophores (a chameleon has only a dozen). Why would an animal have so many ? Why would an ocean animal need more colors?
START and PAUSE at (8.38) and ask, "Why would the winning male flush out the sperm of the previous male?"
START and PAUSE at (12.42) and ask, "What is the size range for squids?"
START and PAUSE at (13.33) and ask, "What is the pen and what did it evolve from?"
START and PAUSE at (16.13) and ask, "What are some of the signs of intelligent behavior?"
START and PAUSE at (23.33) and ask, "Why would the octopus be called the devil fish?" Also ask--what was the size of the hole that the octopus could squeeze through?
START, but PAUSE the video (27.34) before students can hear the answer to the question: "Why would a person be in a hospital and not moving from contact with an octopus?"
START and PAUSE the video at (30.77) and ask, "What are two ways in which a blue ring octopus can poison it's victims?"
START and PAUSE at (32.32) and ask, "Where do the largest octopus in the world live?"
(If using video over two class periods, stop here and ask students to make a note of the image on the screen and of the time code.)
START and PAUSE at (37.42) and ask, "What is the design Flaw ?"
START and PAUSE at (41.90) and ask, "What is the largest squid and how deep does it live?"
START and PAUSE at (42.52) and ask, "How do we know that these animals exist?"
START and PAUSE at (45.56) and ask, "What are the features of the Vampire Squid?"
START and PAUSE at (55.61) and ask "What do Vampire Squids have in the place of suckers on their tentacles?"
POST-VIEWING ACTIVITIES
Squid Lab I uses preserved squid and Squid Lab II uses fresh squid. Squid can be purchased or ordered through your local market. Ask for them whole !
Students should have prior knowledge of safe laboratory and dissection procedures before working on either of these labs.
(See Worksheets attached.)
ACTION PLAN
Visit a local aquarium and look at cephalopods first-hand.
Squid (a.k.a. calamari) are eaten around the world. How are these squid harvested? By whom? Are squid raised commercially anywhere in the world? (Like those other popular mollusks, clams and oysters.)
EXTENSIONS
Visit the Cephalopod web site.
http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/squid_Taningia.html
There are a number of ways to direct students to the website: (1) if your students have e-mail accounts, e-mail the website address to them and have them copy it into Netscape; (2) find and bookmark the website for students; or (3) have students search through Yahoo or any search engine, link to the website and bookmark it.
(Worksheet attached.)
SQUID LAB I
Materials: Preserved squid, dissection tray, hand lens, handouts on squid, colored pencils, rubber gloves, goggles and apron.
Name Period Date
Squid or the flatter cuttlefish are representatives of the class Cephalopoda. Cephalopod means "head foot." Look for the head and foot parts of the squid in preparation for when we look at the rest of the Mollusca phylum. As different as they appear to casual inspection, snails, clams, oysters, slugs, chitons, and cephalopods are all mollusks and are all closely related. This lab will be our first look at the mollusks.
PROCEDURE
(Answer questions on a separate sheet of paper.)
Draw the general shape of your squid. You should get the proportions, coloration and numbers of parts correct.
(How many arms does it have? How many tentacles? Draw a close up, detailed picture of one of the arms complete with suckers.)
What are the purpose(s) of the side fins?
What does the skin look like? Accurately color the skin on your drawing. What might be the purpose of the coloration? What does the skin feel like? What is it's texture? Draw a detailed illustration of the eye.
Locate the mouth and make an accurate drawing of it.
Why would this animal have a rigid tube running the length of its body?
How does this animal fit in the phylum Mollusca? Describe the three main classes of this phylum and give an example of each.
Using the squid illustration handout, label these parts on your own drawing. (Body, Head, Funnel, Eye, Fins, Arm, Beak, Tentacles, Suckers, Mantle.)
(Color the handout, making the titles the same color as the part the title refers to. This does not have to be lifelike, but rather it is to help you recognize the different parts.
SQUID LAB II
Materials: Fresh squid, dissection tray, probes, scalpel or single-edged razor blade, dissecting microscope, handout on squid, rubber gloves, goggles and apron.
Name Period Date
This lab will allow you to explore the internal structures of the squid. As we have studied cephalopods, we have learned that they are very intelligent, especially compared to other invertebrates. They have a highly developed head region with prominent eyes. Make a careful study of the eye of the squid and compare it with a mammalian eye. The circulatory system of a squid is highly developed and in this dissection we will trace these features.
PROCEDURE
(You will be working in groups of 4-6 students for this lab.)
(1) Obtain a squid from your teacher and place in it a dissecting tray. You may use the dissecting microscopes for this lab. Be sure to treat the scopes carefully.
(2) Make one long cut down the body of the squid. You will be told what tool to use in class. Use probes to separate the organs.
(3) Locate the following structures, as illustrated on the overhead. Label and color these features on your handout. (heart, gills, liver, ink sac, eyes, ram jet, visceral mass, beak, radula/tongue, mouth, anus, mantle, funnel)
Are there any eggs present? If so, what is the sex of the squid?
(4) Describe how the ink gets dispersed from the squid. Being careful, because it can stain clothes, take a pin and remove a drop of ink from the ink sac and sign your name below.
(5) Of what use (to a squid) are the two long tentacles?
(6) How does a squid use to move quickly? Why would a squid want to move quickly?
(7) Why does a squid need an efficient circulatory system and brain?
(8) Why are these mollusks considered "head footed?"
(9) Why don't the aliens on shows like Star Trek ever look like cephalopods ?
CEPHALOPODS ON-LINE
http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/squid_Taningia.html
Answer the following questions about Cephalopods:
What are two myths about the Giant Squid?
What is the genus and species name of the Giant Squid?
Where does it live? How do we know? Why is it hard to study this animal?
What does this animal eat?
Compare this Squid with another type of squid--Flasher. What is the biggest Flasher and what is the size range?
How deep in the oceans does this animal live? What is different about this flasher than all other squids?
Look at the map of found Flashers and determine where most of these live.
How are Cephalopods like a snail and a clam?
How many species of the different classes of Mollusca?
What are the pigment cells called on the cephalopods? How do they help this animal survive?
Answer the five questions under the " Inside Story".
