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Water: Middle School

Exercise I. Draw Your Own Pfiesteria!

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Picture of pfiesteria.

Step 1. How big is Pfiesteria?

The size of Pfiesteria is 5-450 Um (micrometers). Compare that with your ruler: 1 millimeter is 1000 micrometers. If the smallest Pfiesteria were lined up on your ruler, 200 of them would fit in 1 mm!

Step 2. What does Pfiesteria look like and what does it do?

Go to Web site 3: "Images of Pfiesteria"[broken] Exit EPA Disclaimer . This Web site contains a photographic perspective of the organism, as seen through microscopes.

Click on Web site 2: "Life Cycles of Pfiesteria pescicida"[broken] Exit EPA Disclaimer , for details on how Pfiesteria actually kill fish.

As you can see, there are many different versions of Pfiesteria. This is because they can take on different forms depending on their particular life-cycle stage. They are in the flagellated, amoeboid, or encysted forms or stages.

Step 3. Make your own Pfiesteria.

Use the empty box on the Draw Your Own Pfiesteria worksheet below to draw a picture of Pfiesteria in one of its stages. Make sure you identify the stage. In your drawing, identify the features that correspond to the descriptive name of the lifestage, and label key features such as the flagella

Picture of a light bulb indicating a new idea. For ideas on how to translate a photograph into a drawing, click on Web site 2: "Life Cycles of Pfiesteria pescicida" [broken]] Exit EPA Disclaimer and enlarge the drawing.

Step 4. Figure out the scale of your drawing.

Picture of a ruler. Measure the diameter of the Pfiesteria in your drawing using a ruler. Now compute the scale of your drawing with respect to a 'real' Pfiesteria.
(Hint: If the diameter of your Pfiesteria is 1 mm, then the scale would be 1:200)  

Worksheet: Draw Your Own Pfiesteria

You may prefer to download and print a PDF Version (1 pp, 450K) of this worksheet.

Name: _________________________ Date: ________________

Name of Stage: _________________________

Scale of Drawing: _______________________

(Your Picture goes here.) spacer

Additional Resources and activities (as time permits):

Investigate the investigators:

Read and print out the news story "Scientists track the 'phantom'" (PDF) (11 pp, 171K) about how Pfiesteria disabled and affected the scientists researching it.

Middle Schools  |  Hysteria Over Pfiesteria  |  Exercises: I  |  II  |  III  |  IV  |  Top

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