Pond Water Protists: Paramecium, Euglena & Chlamydomonas
An online microscope lab for middle school science on StudyScope. Students work through 3 real prepared microscope slides in order: Paramecium (Whole Mount), Euglena (Whole Mount), and Chlamydomonas (Whole Mount).
Three single-celled organisms from pond water, each with a different way of getting around: Paramecium rows with thousands of cilia, Euglena pulls itself along with one flagellum, and tiny Chlamydomonas is a swimming green alga. For each one, students describe what they see, hunt for the structure it moves with, then check against labeled examples. You drive the slides; students follow on their own screens and can pan and zoom. Have students keep a three-column table: "Organism," "How it moves," and "How it gets food." About 30 minutes.
- Grade level
- Middle school
- Time
- 30 minutes
- Subject
- Microbiology
- Slides
- 3
- NGSS
- MS-LS1-1, MS-LS1-2
NGSS alignment
- MS-LS1-1: Provide evidence that living things are made of cells, either one cell or many different types of cells.
- MS-LS1-2: Model the function of a cell as a whole and the ways its parts contribute to that function.
Lab steps
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Paramecium: covered in cilia
Slide: Paramecium (Whole Mount)
- Each of these shapes is one whole living thing, made of a single cell. They are Paramecium, collected from pond water. The red and green colors come from stains added to make them easier to see. Describe their shape. What everyday object do they remind you of?
- Zoom in on this green cell and look closely at its edge. You'll see a fuzzy fringe all the way around. What do you think that fringe is made of? How might it help a Paramecium move or eat?
- Check the labels. The fringe is made of cilia: thousands of tiny hairs that beat together like oars to push the cell through water. They also sweep food (mostly bacteria) toward the cell. Add Paramecium to your table: how does it move?
- Now look at these red cells. Hunt for two things: • a cell with a darker lump inside it • a cell that looks pinched in the middle, like a figure eight What do you think is happening to the pinched cell?
- Check the boxes. The dark lump is the macronucleus, the large nucleus that runs the cell's day-to-day work. The pinched cell is splitting into two new Paramecium. This is called binary fission. If one Paramecium splits in two, and each of those splits again, how many would there be after 3 splits?
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Euglena: one whip-like flagellum
Slide: Euglena (Whole Mount)
- This slide is full of Euglena. Like Paramecium, each one is a single cell. Again, the colors come from stains. Compare them to Paramecium. Are they bigger or smaller? Use the scale bar to estimate. Do you see a fringe of cilia?
- Zoom in on this group. Euglena does not have cilia. Instead, some of these cells have one long, thin thread coming off one end. Find a cell with a thread attached. What job do you think the thread does?
- Check the labels. The thread is a flagellum. Euglena whips it around to pull itself through the water. Living Euglena are green because they have chloroplasts and can make their own food from sunlight. Add Euglena to your table. Is it more like a plant or an animal? Give one reason for each side.
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Chlamydomonas: a tiny swimming alga
Slide: Chlamydomonas (Whole Mount)
- These small green ovals are Chlamydomonas, a single-celled alga. Each oval is one whole organism. Use the scale bar (or the measure tool) to estimate how long one cell is. How does that compare to Paramecium and Euglena?
- Check the box. One Chlamydomonas is only about 8 to 10 micrometers long. You could line up about 20 of them along one Paramecium. Alive, each cell has two flagella for swimming and a big chloroplast for making food. They are too small to see on this slide. Add Chlamydomonas to your table.
- Look back at your table. All three organisms are single cells living in the same pond. Which one is most like an animal? Which is most like a plant? Why do you think scientists put all three in their own group, the protists, instead of calling them plants or animals?
Slides used in this lab
Teach it live
Present the lab live and every student screen follows your slide, zoom, and current step, with students joining by room code on Chromebooks, iPads, or any browser, no student accounts. Add the lesson to your library to edit the steps, reorder slides, and add your own teacher notes.