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Basically, I'm a Fungi
Pronounced by some as “fun guy,” the fungi are part of the
mostly microbial world of decomposers. Along with bacteria, fungi are
responsible for the decay of dead things that would otherwise pile up
around us. Basically, I’m a Fungi makes these organisms readily
observable as cultures that grow on special materials — Petri plates
that contain prepared media that act as a food source. This particular
medium contains a relatively high amount of sugar, which favors fungi
over bacterial cultures.
Two types of fungi may grow in your plates. Yeasts
tend to grow into smooth, spreading circular colonies, while most molds
will eventually
develop into fuzzy growths. It’s not important that you identify
which is which, just that you observe and appreciate the diversity and
abundance of these decay organisms, which can be found on almost every
surface.
Materials Needed
Instructions
- When your Petri
plates arrive, be sure not to open the lids. You’ll inadvertently
introduce microbes if you do.
- To conserve media and make side-by-side comparisons, use
a permanent marker to divide each plate into thirds on both the lid
and the bottom.
- Select surfaces to be tested for the presence of
fungi. A good variety will include soil, water, air (the inner surface
of the bottle),
plants,
and animals.
- In each of the three Petri plates,
write the name of one of the surfaces that you’re testing at the outer edge
of the bottom side of the plate (the top may move around). Consider
making
one of
the sections a “control,” which you do not disturb.
The control can be used to make comparisons.
- Using a sterile
swab for each surface, gently swipe the surface. Take care not
to pick up debris.
- Open the appropriate Petri plate. Start
at the outer edge of the appropriate section and make a streak in
an “S” shape.
Be sure not to press too hard and to keep your streak within
section boundaries.
- Replace the lid and tape it closed.
- Turn each plate upside-down to
avoid a “rain” of condensation
from the lid as the colonies grow.
- Incubate in a warm place.
- Observe microbial growth in your plates
over a two-week study period and record what occurs on your “Basically,
I’m a Fungi” Data
Sheet.
Note: It is safe to culture microbes in this
way — they grow
in a closed container and are types that are already
present in the environment. To dispose of the plates,
spray with disinfectant solution,
seal, and throw away. The only thing to be careful
about is opening the plate during your study — each
time you do, you may introduce new microbes!
Activity Questions
Before you swab your plates:
- What are the distinguishing characteristics
of fungi?
- Which surfaces do you think harbor these microbes?
- How do you think
different surfaces might compare?
After your study period:
- What surfaces did you test for the presence of fungi?
- Describe the
growth that resulted from testing these surfaces.
- How did different
surfaces compare?
- Were you surprised by your results? Why?
- What can you conclude about
fungal life in your EcoColumn?
SHARE YOUR RESULTS: Basically, I'm a Fungi
TRACK OUR PROGRESS: Basically, I'm a Fungi
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