Name:__________________________ Period: 1 2 3 4 5 6 7 Date:____________________
Planaria
Regeneration Lab
Background Information:
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. The purpose of this lab is to observe the
anatomy, nervous responses, feeding, and regeneration of the planaria.
Lab Materials:
Living Planaria
Petri Dish
Spring Water
Egg Yolk
Hand Lens
Pen Light
Pipettes
Epsom Salt
Table Salt
Scalpel
Probe
Black Paper
Lab Procedure and Questions:
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 of the dish.
2. Examine the animal using a hand lens.
A. Describe the dorsal (back) surface of the planaria.
B. Make a drawing of the dorsal surface and label the parts you are able to see.
C. Describe the way in which the planaria 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.
C. Using the penlight or a flashlight, shine a beam of light on the anterior region and the eyespots. What is its
response?
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 your worm 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. If needed get fresh water for your planarian.
Scientific Method in Action:
On a separate piece of paper you are going to be using all 7 steps of the scientific method as you experiment on how
the process of regeneration happens with your planaria. You will need to write out each step in as much detail as
you can outline what you specifically did during each of the seven steps. Some of the steps you have already taken
on this assignment will help you with the first several steps of the scientific method. The following instructions
below will help you with steps #4 and #5 of the scientific method.
8. Add a few crystals of Epsom salts to the water in your Petri dish and 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 and follow the planaria care information provided in class, and record your care
daily in the chart.
Planaria Care Chart:______________________________ Planarian’s Name:___________
Date
Care Given
Growth Measurements and Observations
Care and Maintenance of Planaria
1. Keep its water clean and change it daily. Use only spring water! Chang the water only when the planaria are
settled. The planaria will stay attached to the side of the container so you need to gently pour the water out, and then
refill it.
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 during this time.
3. Allow them to eat for about 30 minutes and then transfer them to fresh water. Do not leave any egg 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.