• Critters of Ackley Lake - Exploring Protozoa in the Classroom

     

  • Sophomore biology students have been keeping field journals to document the natural world around them, ask questions about life processes, and connect ideas in class to real-world practice.  While journaling out on Ackley Lake, students collected samples of water from the shore

    Back in the classroom, we examined the  samples under a microscope.  Students discovered a world of cilliates, euglena, fungi and algae.  We used a cell phone mount to record some video and pictures of what we found, and students each completed a field journal entry.  We'll revisit these critters later in the year when we discuss cellular structure and processes.

Cilliates

  • Some tips for exploring protozoa at home or in your classroom:

    • Collection. Collect water by squeezing plants, moss or algae from a pond or stream into an empty plastic container.  Lowering a cup until it is just above the surface of the substrate (mud) and tipping it upward is another strategy to help capture something cool.
    • Use Care. Don't shake the sample; don't leave it in a sealed plastic bottle where it will cook in the sun; examine the sample soon after collection.
    • Saving a Sample. When the sample has to be saved for several days, I pour the water into a small fish tank or other wide flat container and add a couple pieces of boiled grain and air pump/air stone made for aquariums.  The grain provides a food source for bacteria that many protists eat.  The air stone will oxygenate the water which is necessary for community of organisms in it - but it can also prevent toxic blue-green algae growth.  I've heard to keep the sample away from sunlight - I think that is to prevent it from heating or growing blue-green algae - but I usually put a plant light on it to keep the plants and photosynthetic spirogyra alive and haven't had issues
    • Microsope Use. Use a convex slide, place a couple drops of the sample into the dimple.  Hold a slide cover at a 45 degree angle on the slide and allow it to tip onto the drop to avoid air bubbles.  Microscopes don't have to be very high quality or high magnification.  A plastic scope capable of 40x magnification is sufficient.  Just keep the lenses and objectives clean.
    • Smartphone Microscope Adapter. An inexpensive adapter that holds a smartphone on the tube is invaluable for working with students.  Use it to stream from your phone to a larger screen for all students to see.  Use it to shoot video or photos that can be referenced later. Use it to increase accessiblity for all students.
    • A Guide to Protozoa.  Mic-UK has a nice basic online guide that can be used to help identify specimins that are collected.  I also like to use Van De Graaff's Photographic Atlas for the Biology Laboratory or Leboffe and Pierce Photographic Atlas for the Microbiology Laboratory.  They are handy references for the biology classroom.