Squid Dissection Activity & Report

Student Name: ______________________________________

 

Squid

Anatomy

Now that you have learned about mollusks, here is another “hands-on” opportunity for you to show what you know by investigating one of the more complex mollusk species, the squid.  In this activity, you will dissect a squid and identify and describe some of its special adaptations.

 

 

 

Objective

To observe and describe the functions of special adaptations of the most highly developed class of mollusks and to describe the general characteristics of mollusks.

 

Materials

Squid (Calamari or Atlantic longfin squid, Loligo pealei)

Dissection pan or tub

Scissors, Scalpel, Dissection pins and probes

Textbooks, lab manuals or guides with squid diagrams

 

Safety

Remember to follow your lab safety techniques (according to your school’s safety contract).  Dispose of the specimen properly and wash your hands and materials after you complete your dissection.

 

Procedure

Obtain a squid (Calamari) from a local grocery store or a fishing bait and tackle shop.  Thaw out your specimen and place it in a dissection pan or tub.  Remember to use your lab safety techniques and follow the directions below to complete your dissection.  You can also obtain additional guides or lab manuals from your teacher to help in your identification of squid anatomy.

 

A.

External

Anatomy

Look closely at your squid and identify the following structures:  mantle, siphon, chromatophores, tentacles, suction cups, eyes, mantle cavity.  Use the diagram to help you find these structures.   

 

Draw a picture of the squid on your lab report form.  Identify the names and functions of the structures you identify.  Identify the dorsal and ventral sides of the squid.

 

 

B.

Internal

Anatomy

Carefully cut through the mantle to find internal organs.  Slit open the mantle cavity by inserting the tip of the scissors under the mantle at the siphon and cut all the way up to the dorsal end.

 

Examine the mantle cavity.  Note the muscular body wall.  Identify the siphon, collar, and the two gills.  Locate and remove the pen (the vestigial internal shell).

Remove the siphon and cut into head region.  Find the squid’s beak  and tonguelike radula.  Try to locate the esophagus (surrounded by the liver) and follow it to the stomach.  Note the large caecum connected to the stomach.  The intestine then runs from the stomach to the rectum.  Note the ink sac (used in defense).

 

 

Go Further!

Attempt to locate the heart (transparent structure), nephridium (kidneylike excretory organ), and the squid’s cranium (which contains the brain).  Determine the sex of your specimen.  The male has testes that lie beneath the caecum.  The female has a large egg mass and two large nidamental glands (that produce a covering for the eggs).  Remove the eye and cut it in half.  Identify the transparent lens and the shiny black retina.

 

Draw a picture of the internal anatomy of the squid on your lab report form.  Identify the names and functions of the structures you are able to identify.  Then answer the analysis questions following your drawings.

 


 

 

Squid Dissection

Report Form

Name____________________________________________ Date __________

 

External Anatomy

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Internal Anatomy

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

Questions for Analysis

 

1.  Describe how a squid moves. How is this different from the mud snail?

 

 

 

 

 

2.  What features of the squid show that it is adapted to be a predator?  How is this     different from the mud snail?

 

 

 

 

 

3.  Another special adaptation of the squid is its ability to change color.  What might     be the advantage of this special ability?

 

 

 

 

 

4.  What features of the squid are common to all members of the phylum Mollusca?