flatworm
 
 
Lab Study:  The Planaria
 
Background: 
 
The planaria is a free-living flatworm, belonging to the Phylum Platyhelminthes. They are able to react to various stimuli and they are known for their remarkable  power to regenerate.

 

Purpose:  To observe the anatomy, nervous responses, feeding, and regeneration of the planaria.

 

Materials:         living planaria                egg yolk                       pipettes

                        scalpel                          petri dish                      hand lens

                        Epsom salts                  probe                           spring water     

                        pen light                        table salt                       black paper

 

Procedure:

 

1.  Remove a planarian from the jar at the front of the room using a pipette. Place it in a petri dish with enough water to just cover the bottom.

 

2.  Examine the animal using a hand lens.

     A.  Describe the dorsal surface.

 

 

     B.  Make a drawing of the dorsal surface and label the parts you are able to see.          

 

 

 

 

            C.  Describe the way in which it moves.

 

 

3.  Check the planarian’s reaction to various stimuli.

            A.  Create a current in the water of the petri dish using a pipette.  How does it react?

 

 

            B.  The projections on each side of the head are called auricles.  Touch them with the                            probe.  How does the animal react?     

 

 

            C.  Touch the other areas of the body and describe its reactions.

 

 

            D.  Place a crystal of table salt in the water (DO NOT PUT THE SALT ON THE                                            ANIMAL!).  Describe its reaction.  Then, carefully change the water.

 

 

 

4.  Carefully hold the planaria above your head to observe the ventral side.  Use your hand lens.

            A.  Describe the ventral surface.

 

 

            B.  Make a drawing of the ventral surface and label the parts.

 

 

 

 

 Using the penlight, shine a beam of light on the anterior region and the eyespots.                                    What is its response?
 
 

 

bo 
 
 

6.  Using your pipette, carefully move the planaria to the center of the petri dish.  Place a lid on top that has been partially covered with black paper.  Record below under which type of lighting the planaria seems to spend the majority of its time (observe for a few minutes to determine

this). 

 

 

7.  Bring your planaria to the front of the room and obtain a small piece of egg yolk.  Place it in the dish and observe the planaria feeding for 10 minutes.  Record your observations below.  Then, remove the egg yolk from your petri dish.

 

 

 

Add a few crystals of Epsom salts.  Wait a few minutes.  The planaria will be anesthetized.  Decide how you will cut your planaria to allow it to regenerate.  See the diagram below for possible cuts.  With a razor blade, cut the planaria in the desired location and transfer each half to a separate jar with a little spring water.  Make only one cut.  Follow the planaria care information provided in class, and record your care daily in the chart. 

 

 

 

 

 

 

 

 

 

 

Planaria Care Chart                                                      Name:  _______________

           

                Date

             Care Given

           Observations

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Care and Maintenance of Planaria

 

1.  Keep its water clean and change it daily.  Use only spring water!  Change the water only when they are settled – they will stay attached to the side of the container – gently pour the water out, then refill. 

 

2.  Planarians should be fed once a week.  They love fresh egg yolk, and will eat liver if you have any around.  Don’t be surprised if your new pet doesn’t eat during the first week – they are busy regenerating!

 

3.  Allow them to eat for about 30 minutes and then transfer them to fresh water.  Do not leave any yolk in the water with them.

 

4.  Keep them in a cool, dimly lit area.  They do not like too much light!

 

5.  It is your responsibility to watch and care for your planaria!  Do not place them in a place where something could happen to them.  Negligence will affect your grade.

 

 

 

 

Care and maintenance of Planaria

 

1.  Keep its water clean and change it daily.  Use only spring water!  Change the water only when they are settled – they will stay attached to the side of the container – gently pour the water out, then refill. 

 

2.  Planarians should be fed once a week.  They love fresh egg yolk, and will eat liver if you have any around.  Don ’t be surprised if your new pet doesn’t eat during the first week – they are busy regenerating!

 

3.  Allow them to eat for about 30 minutes and then transfer them to fresh water.  Do not leave any yolk in the water with them.

 

4.  Keep them in a cool, dimly lit area.  They do not like too much light!

 

  1. It is your responsibility to watch and care for your planaria!  Do not place them in a place where something could happen to them.  Negligence will affect your grade.

 

 

 

 

 

 

 

Congratulations!  You’ve Just Had a Planaria!

 

You have each been given one half of a planaria.  Remember that planaria can regenerate, so by the time you are finished caring for your planaria, you should have 1 complete organism.

 

The Guidelines

 

Remember that this planaria is yours to care for.  You must treat it with love, kindness, and respect.  The way you treat your planaria as a child will ultimately determine how it behaves as an adult.  Make sure that it accepts responsibility for its actions, treats others the way it would want to be treated, and carries itself with dignity, modesty, and honor.

 

Your planaria must have a name.  Remember that planaria are hermaphrodites, so you have the choice to give your planaria a boy name or a girl name.

 

Planaria Care

 

Caring for your planaria is a 25 point project

 

You will receive 10 points for completing your planaria care sheet.  I will periodically check your care sheet, so make sure that it is filled out and up-to-date.  If your sheet is not filled out and up-to-date, you will lose 5 points.  They will be checked in class at random. 

 

The planaria is your baby!  You must care for your planaria!  To ensure that you are exhibiting the proper behavior of a planaria parent, we will be checking to make sure that you have your planaria on your person while in school. 

 

You must have your planaria with you at all times while in school (7:30 – 2:15).  The exception to this rule is gym class.  Although your planaria won’t like it, you must leave your planaria behind when in gym class.  They should be safely locked in a locker.  No sympathy will be given for stolen planaria due to your negligence.

 

You may be asked to present your planaria at anytime during the school day.  Any teacher may ask you to show your planaria, so beware!

 

The parent (that’s you) loses 5 points off their planaria lab each time that they are caught without their baby planaria.

 

Your babies will be due for a final check-in on May 5th.  Good luck and good parenting!

 

It’s important to be a caring parent!  Dead planaria will result in the loss of 5 points off your planaria project.

 

You may make up the 5 points for your dead planaria by composing a 1 paragraph (4-5 sentences) explanation as to why you think your planaria died.  You need to give an honest evaluation as to the circumstances that led to your planaria’s demise.