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What these single-celled, gelatinous blobs lack in brain power, they make up for with surprisingly complex decision-making.

About This Video

Grade level: 6-13+
Length: 5 minutes
Next Generation Science Standards: MS-LS1.A, MS-LS1.D, HS-LS1.A

Summary

Slime molds don’t look like much. Amorphous and gloppy, they spread across the forest floor in a mindless quest to consume whatever lies in their path. But research scientists are now learning that the routes slime molds take through their environment are anything but random. Despite their lack of a brain—or even a neuron—these organisms have evolved a very clever, physical way of making decisions about where to go to find the best food sources. Because slime molds move so slowly (just a few centimeters a day), it’s necessary to speed up time to truly understand their complex behaviors. Simon Garnier and his team at the New Jersey Institute of Technology’s SwarmLab use time-lapse macrophotography in their research, and with these techniques are beginning to unravel the nature of these organisms’ “brainless intelligence.” By better understanding how slime molds move and make decisions, Garnier’s team hopes to shed light on how intelligence may have evolved in the first place.

Video Discussion Questions

  1. What are slime molds?
  2. What does it mean to say that slime molds have a 'brainless intelligence'?
  3. Why do the researchers in the video use time-lapse video to study slime molds?
  4. How do slime molds 'make decisions'?
  5. Where might the intelligence of a slime mold reside within it?
     

Classroom Activities to Accompany This Video

3-2-1

3-2-1

Have students choose a time lapse sequence from this video and watch it without sound. In their science notebooks, ask students to write down:

  • 3 things they noticed or observed
  • 2 questions they have or things they wonder about, and
  • 1 thing they learned

On the board, draw a table with three columns labeled 'I noticed...', 'I wonder...', and 'I learned...'. Have students discuss their observations, questions, and knowledge gained, and write these things in the appropriate column on the board. In addition to the following questions, you can use the discussion questions listed in About This Video to engage your students in a deeper dive into slime molds:

  1. What is the purpose of time-lapse video?
  2. How can time-lapse video be used in research, particularly in slime mold research?
  3. What slime mold behaviors can you observe with the time-lapse video that you wouldn't necessarily be able to observe otherwise? Did time-lapse video give you any insight into how slime molds make decisions?
  4. What other applications of time-lapse video can you think of?

Cultivate Your Own Slime Molds!

Slime mold in a petri dish

Your students can test the brainless intelligence of slime molds firsthand by cultivating slime molds in the classroom and challenging the slime molds with a variety of tests, like navigating mazes!

Materials

  • Physarum polycephalum plate culture (can be ordered from science supply companies)
  • petri dishes filled with agar
  • paper towels
  • old-fashioned (not instant) oatmeal flakes

How to Cultivate Slime Mold

  1. Cut a piece of paper towel so that it can cover the bottom of the petri dish completely and hang over the sides. 
  2. Put the Physarum polycephalum on the paper towel in the dish.
  3. Sprinkle water on the paper towel until it is just moist.
  4. Add an oatmeal flake near the Physarum polycephalum.
  5. Put the lid on the petri dish and store the petri dish in a dark place at room temperature. Slime mold are sensitive to light.
  6. Once a day or every few days, sprinkle the slime mold with water and add a couple more oatmeal flakes to the dish. 

Slime Mold Investigations

As soon as their slime molds start growing, your students can devise an experiment to test their 'brainless intelligence.' After coming up with a testable question—such as 'can a slime mold navigate through a maze to obtain food?'—and making a hypothesis, students should design an experiment to test their hypothesis. Here is an example of such an experiment:

As always, make sure your students understand and follow proper lab safety procedures and that all petri dishes are properly and carefully disposed of at the end of the investigations.

Video Credits

Produced by Spine Films, this video appears in bioGraphic, a magazine powered by the California Academy of Sciences to showcase both the wonder of nature and the most promising approaches to sustaining life on Earth.

Additional Resources

California Academy of Sciences News: The Blob Remembers
Read more about how slime molds have 'spatial memories' even though they don't have a brain!

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