• HARRIS PORTER

Sponsored Links

  •   
  • FileName: SixthGrade_Microorganisms.pdf [read-online]
    • Abstract: HARRIS PORTERFIELD TRIPMicroorganismsTheme Pothole Point in the Needles District ofMicroorganisms play a vital role in the high Canyonlands. Potholes are ephemeral and

Download the ebook

HARRIS PORTER
FIELD TRIP
Microorganisms
Theme Pothole Point in the Needles District of
Microorganisms play a vital role in the high Canyonlands. Potholes are ephemeral and
desert ecosystem. They are everywhere! dynamic, so don’t count on a full pothole
unless you’ve visited it very recently. Activity
Utah State Science Core Curriculum Topic in potholes is greater when the water is
Standard Five: Students will understand warmer, from late spring through fall. Lichens
that microorganisms range from simple to are found almost everywhere there is rock;
complex, are found almost everywhere, and you’ll need south-facing and north-facing
are both helpful and harmful. rock slopes for the investigation. Cryptobiotic
Objective One: Observe and summarize soil is extensive in southeastern Utah; a place
information about microorganisms. with crypto islands in slickrock is most easily
Objective Two: Demonstrate the skills examined without damaging the soil.
needed to plan and conduct an experiment
to determine a microorganism’s Times
requirements in a specific environment. Pre trip is 30 minutes
Objective Three: Identify positive and Field trip lessons are each one hour
negative effects of microorganisms and how Post trip is 45 minutes
science has developed positive uses for
some microorganisms and overcome the Science Language Students Should Use
negative effects of others. Algae, fungi, microorganism, decomposer,
single–celled, organism, bacteria, protozoan,
Field Trip Location producer, hypothesis, experiment,
Accessible pothole locations include Sand investigation, variable, control, culture
Flats Recreation Area east of Moab and
Background
Microorganisms are everywhere and play many cells, sometimes forming chains or colonies.
important roles in the high desert ecosystem. They get their nutrition in a variety of ways.
Some microorganisms are plants or animals, 3) Fungi are molds and mushrooms. These
but some belong to the other three kingdoms have a multicellular filamentous form with
of living things. Some sixth-grade students specialized complex cells. They absorb food.
may be familiar with the kingdoms and may 4) Plantae are plants, including mosses, ferns,
ask about them, so here’s an update or review. woody plants, and non-woody plants. These are
1) Monera consists of bacteria, including multicellular forms with specialized complex
cyanobacteria. Monerans are small, simple, cells; they photosynthesize. 5) Animalia
single cells, and sometimes form chains or mats. includes everything from sponges and worms to
Some absorb food; some are photosynthetic. mammals. Animals are multicellular forms with
2) Protista includes protozoans and algae of specialized complex cells. They ingest food.
various types. These are large, complex, single Viruses aren’t included in the kingdoms because
Studying pothole organisms
Sixth Grade Curriculum 5
they are on the borderline between living and array of small organisms and microorganisms.
non-living things. They are noncellular parasites Pothole dwellers have unique adaptations,
that cannot live or reproduce outside of a living enabling them to survive in this feast or famine
organism. environment. Most of these organisms have
shortened life cycles, reducing the length of
Probably, the most fragile component of this time they are dependent on water, and thus
arid region is cryptobiotic soil crust. The crust allowing them to live in shallow, short-lived
is a community of microorganisms, including pools. The life cycles of clam shrimp and fairy
cyanobacteria and a variable mix of lichens, shrimp are 5-10 days. The life cycle of a tadpole
fungi, and mosses. This network of organisms shrimp is 12-14 days. Tadpole shrimp, as a result,
plays a vital role in erosion control, nitrogen require deeper potholes in order to survive.
fixing, and moisture absorption. One footprint
can destroy years or even decades of this soil’s A pothole’s size determines its diversity and
growth, and new growth often has a different species make-up. Microorganisms, such as
mix of organisms than that of the previous single-celled algae and protozoans, inhabit
crust. shallower pools. Slightly deeper pools might
have tiny worm-like larvae of midges wriggling
Rock lichen is composed of another community around their bottoms. The deepest and largest
of microorganisms, namely fungi, with algae, pools might contain a variety of tiny crustaceans
cyanobacteria, or both. That’s two or three and insects: fairy shrimp, clam shrimp, tadpole
kingdoms intermeshed. Fungus forms the shrimp, water striders, back swimmers, water
tough outer layers of lichen, while algal (and/or boatmen, and whirligig beetles.
cyanobacterial) cells enmeshed in fungal
threads compose the inner layers. The lichen A pothole is a unique habitat that is very easily
structure is more elaborate and durable than disturbed. Pothole organisms are sensitive to
either fungi or algae alone. Dry lichens have the sudden water chemistry changes (brought on by
ability to absorb more than their own weight sunscreen, for example), temperature changes,
of water. They can carry on food production at sediment input, being squashed, and being
any temperature above 32ºF. Temporary water, splashed out onto dry land.
such as dew, can be taken almost directly into
the algal cells of the lichen; the water does not
need to go through roots and stems as it does in
vascular plants.
Desert potholes provide homes to a fascinating
Seedling in cryptobiotic soil crust
6 Canyon Country Outdoor Education
PRE-TRIP ACTIVITY
Mystery Photographs
Objectives write each organism’s name next to its photo
Students will be able to: number. Model one example on the board;
a. Define the term microorganism. illustrate that the first one that they figure out
b. Name at least two kinds of microorganisms will probably not go on the first line on their
and their functions. paper. Circulate among the groups as they
work. If available, hand out books with color
Materials photographs of microorganisms to groups that
Six copies of a numbered set of photographs finish early.
of microorganisms (from Kuhn, 1988: 30-33;
Nardo, 1991: 39, 60, 63; Ricciuti, 1994: 11, 47); 3) Reconvene the students as a whole group. Go
seven copies of Mystery Photographs Description over the answers, re-reading and discussing just
Sheet; optional: books with color photographs the descriptions that students found difficult to
of microorganisms. match.
PROCEDURE 4) Preview the field trip, telling students that
they will be looking at a couple of different,
1) Ask students to define the term small communities of organisms, using hand
microorganism. Probe them for how much they lenses and microscopes to get close-up looks,
know about microorganisms. Be sure they know and completing some scientific experiments.
the basic definition of a microorganism: An Review the items that students need to bring to
individual organism that cannot be seen without school on the day of their field trip.
the aid of a microscope.
2) Break students into six groups. Have
each group number a sheet of paper from
one to thirteen. Each group will get a set of
numbered photographs of microorganisms
taken through microscopes. They will also get
a sheet with a description of the organisms in
the photographs. However, the descriptions
are not in the same order as the numbered
photos. Their job, as a group, is to match the
descriptions to the photographs. Tell students
to read the descriptions closely for clues and to
Studying microorganisms through a
microscope
Sixth Grade Curriculum 7
MYSTERY PHOTOGRAPHS DESCRIPTION SHEET
Because the foot-shaped paramecium is The hairy pneumonia bacteria pictured here is
transparent, you can see its dark nucleus. The starting to divide in half.
paramecium filters smaller protozoans and
bacteria from the water to eat. Proteus mirabilis bacteria is normally present
in your intestines, where it feeds on nutrients. It
Spyrogyra are algae that form floating green looks like a hairy hotdog.
masses on ponds. Their spiraling green bands of
chloroplasts are the sites where photosynthesis Yeasts are a type of microscopic fungus. Some
takes place. of them are used for making bread and pizza
dough. Magnified 40,000 times, this one looks a
Desmids are one-celled green algae that can bit like a pizza itself.
look like stars, balls, rods, ovals, or figure eights.
In great numbers, they may tint the water green. Fungi and bacteria are decomposers at work
on some dead plant roots in this microscopic
Shrimp and lobsters have a microscopic view. Look for something that looks like plant
relative called a water flea, a roundish animal roots.
with a small head and feathery antennae. The
antennae allow the water flea to swim jerkily This could be an enlarged view of the leftovers
through pond or pothole water. from your last visit to the dentist. (Haven’t
been lately? Then they’re probably still in your
Hydras are almost-microscopic animals that mouth!) These bacteria in dental plaque are
look like squids or octopuses. Their tentacles shaped like short and long worms.
have stinging cells to paralyze prey such as water
fleas. The threads holding these sand grains together
are actually sheaths of cyanobacteria, the main
An armored amoeba called a foraminiferan organism in cryptobiotic soil crusts.
makes a multi-chambered shell that drops to the
sea bottom after it dies. Where these animals Amoebas are one-celled protozoans that move
are abundant their shells form chalky limestone by changing shape and pushing out pseudopods
layers. The pyramids of Egypt are made of (false feet) in whatever direction they want to go.
cut blocks of limestone made up of these
foraminiferan shells.
8 Canyon Country Outdoor Education
STATION ONE
Life in a Pothole
Objectives observe and catch pothole organisms. Caught
Students will be able to: organisms should be placed in a tray for closer
a. Identify at least three species of animals in a observation with hand lenses. Try to catch a
pothole. smaller organism, and mount it on a slide under
b. Explain at least one reason why diversity is the microscope. Once students look, they often
beneficial to a pothole ecosystem. become interested in the smaller organisms.
Encourage students to use identification sheets.
Materials Review main organisms so students learn their
Dip nets; trays; hand lenses; microscope and names.
slides; Pond Life (Reid 1967); Pothole Organisms
identification sheets; Life in a Pothole Data 3) This step takes 10-15 minutes. Gather
Sheet; clipboard; calculators. students, and discuss diversity, first in a general
sense and then in a biological one. Tell students
PROCEDURE that biological diversity is usually measured by
the number of species present. Have students
1) Give a 5- to 10-minute pothole introduction name the species found in the pothole they
to two pothole groups. Avoid making it any just viewed, and list them on a laminated sheet.
longer; much can be covered during observation Explain that students will be using a diversity
time. Topics to cover during the station should index to determine how rich the pothole is. To
include: (1) habitat limitations in pothole calculate the index, they will need to estimate
communities, such as drying up, temperature the total number of individuals of each species.
extremes, and water chemistry variations; (2) Explain how they might do that in the pothole,
adaptations, especially short life cycles and and give them a few minutes to come up with
how organisms survive dry periods; (3) types of estimates. Show students the diversity index
organisms students may see, including insects formula, and hand calculators to two volunteer
(especially larvae), which mostly spread by students as you go through its calculation with
adults laying eggs in pools, and crustaceans the entire group. Discuss how the index might
(related to shrimp and lobsters), which mostly be used to compare the diversity of different
survive as eggs in sand/mud during dry periods. potholes.
You may also discuss micro versus macro
organisms; (4) pothole formation process, or 4) If the potholes are diverse, just save about
simply mention that these depressions are 5 minutes to observe the second pothole and
rare in the world, but common in the Navajo make a qualitative comparison with the first.
Sandstone. Stress the expectations of students (In this case, have the dip nets put away for
while they are observing the potholes (i.e. the second pothole.) If the potholes are not
where they may stand, not getting into potholes, diverse, have the two groups split the time more
and how to catch and release organisms). evenly between potholes, and calculate diversity
indexes for both. (Collect a sample of pothole
2) Separate into two groups, and go to two water for post-trip activity.)
different potholes. Help students while they
Tadpole shrimp
Sixth Grade Curriculum 9
POTHOLE ORGANISMS
AUDREY GRAHAM
1. Water Flea
2. Water Boatman
3. Mosquito Larvae
4. Tadpole Shrimp
5. Fairy Shrimp
6. Red-spotted toad tadpoles
7. Backswimmer
8. Snails
9. Gnat larvae
10. Clam Shrimp
See also Williams 2000, 172-173.
10 Canyon Country Outdoor Education
DATA SHEET
Life in a Pothole
Species Name Number of Individuals
#1
#2
#3
#4
#5
#6
#7
#8
#9
#10
Total number of Species = Total number of Individuals =
Diversity = Total number of species / Square root of total number of individuals =
Sixth Grade Curriculum 11
STATION #2
Lichens Up Close
Objectives the rocks.”
Students will be able to:
a. Identify rock lichens and name two lichen 2) (Note: You may choose to reverse the order
components. of 2 and 3.) Tell students that they will be using
b. Name one role of lichens in the high desert hand lenses and microscopes to examine the
ecosystem. area’s lichen. Ask each student to write down
c. Explain the basic steps of the scientific process. two observations he/she makes with the hand
lenses and two observations he/she makes with
Materials the microscope. Give boundaries, and hand
Hand lenses; name tags (algae; fungus; water out hand lenses. Have half the group start with
and minerals; sunlight; oxygen; carbon dioxide; the microscopes and half with the hand lenses.
photosynthesis); pictures of lichens (e.g. Afterwards, have students sit back down and
Sharnoff, 1997, 58-71; Corbridge and Weber take turns reading at least one observation each.
1998); microscope and slides; quarter sheets of
blank paper for observations; copies of Science 3) Show students lichen photos, as you talk
Investigation Form and Data Collection Sheet: about lichens. Review why they are important:
Do Lichens Like Sun or Shade? (back to back);
cardboard plot frames; pencils; clipboards; • They grow all over world and may be
measuring tapes; compass. important, like trees, in the carbon dioxide-
oxygen balance in the air we breathe.
Note
If possible, prepare a lichen slide for the • They are important as air pollution
microscope before the station begins. indicators.
PROCEDURE • They sometimes help archaeologists in dating
ruins. (Discuss how lichens grow and their
1) Start by briefly pointing out both lichens and rates of growth.)
mosses on nearby rocks. Make sure that the
students can distinguish between them. Then • Some hummingbirds make nests with them.
have students sit in a group. Tell them that a
lichen is made up of two organisms, and ask • In other parts of the world, reindeer and
if they know or can guess what these are. If a monkeys eat them. Traditionally, some
student answers fungus or algae, have her stand northern Native Americans ate them when
up and put on the corresponding nametag. other food supplies were low.
Prompt as needed. Then, ask students to name
something that plants need. As they answer, • Some are used as dyes.
hand out corresponding name tags, and explain
that the fungus attaches to the rock and brings 4) Save about 35 minutes for the second part of
in most of the water and minerals. Have the this station, a scientific investigation concerning
person with the water and minerals nametag lichen growth in this area. Pass out clipboards,
stand next to the fungus. Have the people with pencils, and back-to-back copies of the Science
the carbon dioxide and sunlight nametags stand Investigation Form and Data Collection Sheet: Do
around the algae. Explain that algae is the only Lichens Like Sun or Shade. Instruct students to
organism of the two that can photosynthesize work in pairs. Go over the steps of a scientific
(make food from these ingredients). Because investigation, as needed. Have students write in
algae gives off oxygen during photosynthesis, the question: “Do more lichens grow on north-
have the person with the oxygen nametag point facing rocks or on south-facing rocks?” For their
away from algae. Give the photosynthesis tag prediction/hypothesis, students should write
to the last student, or have algae hold it. Re- whether they think there will be more, less, or
emphasize that the algae makes most of the the same amount growing on the north-facing
lichen’s food. Mention, however, that fungus rocks. Explain that procedure means the way
attaches to rock, bringing in much of the water in which they will conduct their experiment.
and minerals necessary for making food. An Explain some factors of good procedure,
amusing review, that students will remember, including random selection of plots on their
goes something like this: “Allen Algae and Frieda chosen rock faces and no altering of data to fit
Fungus took a lichen to each other. After they what they have predicted. Demonstrate a way
married, Allen did the cooking, and Frieda built of randomly selecting plots. Go over the data
the house. But, I hear that their marriage is on collection sheet. Take time to explain aspect,
12 Canyon Country Outdoor Education
and review compass directions. Demonstrate EXTENSION
how to measure smallest and largest lichens
and how to estimate percentages of cover by Have students “advertise” in a newspaper
lichens. (Explain that the data sheet asks for article the use of lichens in a new household
more information than is needed to answer our product or a technological breakthrough.
particular question, but scientists often collect The advertisements must include basic lichen
extra data because it can eventually lead to information and their important role in an
more interesting questions and hypotheses.) ecosystem.
Have students fill out the procedural steps they
will use.
5) Give students boundaries, and have them
investigate as many plots as possible on one
slope. When their time is half over, have them
switch to the opposite-facing slope.
6) Gather students, and discuss their results.
If the students haven’t already figured this out,
more lichens, and more types, grow on north
aspects. Their conclusion might be related to
why there are more lichens on north-facing
slopes (i.e. lichens seem to thrive in moister,
cooler locations). Tell students they have just
completed a scientific experiment using all the
elements of the scientific method. Are there
other questions about lichens they could ask?
Reemphasize the important roles of lichens.
Studying lichens
Sixth Grade Curriculum 13
SCIENCE INVESTIGATION FORM
Lichens up close
Scientists’ Names: ______________________________________________ Date: _________________________________
QUESTION
PREDICTION OR HYPOTHESIS
PROCEDURE
List step by step.
RESULTS
What actually happened?
CONCLUSIONS
What did we learn or what do our results mean?
14 Canyon Country Outdoor Education
DATA COLLECTION SHEET
Do More Lichens Grow on North-Facing Slopes or South-Facing Slopes?
Plot#1 Plot#2
Aspect: _________________________________ Aspect: ___________________________________
# of Colors: _____________________________ # of Colors: _______________________________
Smallest:________________________________ Smallest: _________________________________
Largest: ________________________________ Largest: __________________________________
% of Coverage: __________________________ % of Coverage:____________________________
Plot#3 Plot#4
Aspect:___________________ ______________ Aspect: ___________________________________
# of Colors: _____________________________ # of Colors: _______________________________
Smallest:________________________________ Smallest: _________________________________
Largest: ________________________________ Largest: __________________________________
% of Coverage: __________________________ % of Coverage:____________________________
Plot#5 Plot#6
Aspect:___________________ ______________ Aspect: ___________________________________
# of Colors: _____________________________ # of Colors: _______________________________
Smallest:________________________________ Smallest: _________________________________
Largest: ________________________________ Largest: __________________________________
Sixth Grade Curriculum 15
BACK-UP STATION
Cryptos Up Close
To be used in place of station #1 if potholes have dried up note the changes. The mosses swell up, absorbing
or are too muddy for observation; one hour.
moisture, and turn bright green.
Objectives
4) Tell students that there is another function
The students will be able to:
of cryptobiotic soil that is impossible to see.
a. Identify cryptobiotic soil.
Ask if any students have seen their parents add
b. Name at least two functions or roles of
compost or fertilizer to plants. Explain that, like
cryptobiotic soil in the high desert ecosystem.
fertilizer, the lichens in cryptobiotic soil add
c. Explain the basic steps of the scientific process.
nitrogen to the soil. Only a few kinds of plants
d. Measure and record cryptobiotic soil crust data.
add nitrogen (e.g. beans, alfalfa, cryptobiotic
crusts), but nitrogen is essential for other plants
Materials
to grow. Review the cryptos functions as a soil
Disturbed chunks of cryptobiotic crust for
stabilizer and water absorber.
examining; microphotographs of cyanobacterial
sheaths; hand lenses; microscope and slides;
5) Explain to students that they are going to do
bottle of water; eye droppers; copies of Science
a scientific investigation to answer a question
Investigation Form and Cryptobiotic Soil Data
about cryptobiotic soil in this area. Pass out
Collection Sheet (back to back); rulers; pencils;
clipboards with the Science Investigation Form
clipboards; calculators; optional: polysaccharide
and Cryptobiotic Soil Data Collection Sheet (back
sheath model.
to back) and pencils. Students may work in pairs
or on their own. Review the steps of the scientific
Note
process, as needed. Have them write the question
If possible, prepare a microscope slide showing
that they will try to answer: “Is the cryptobiotic
cyanobacterial sheaths before the station begins.
soil bumpier in one area than in another?” Show
them the two areas that they’ll be comparing,
PROCEDURE
and have them make and write their prediction/
hypothesis. Explain factors of good procedure,
1) Have students sit within a few feet of cryptobiotic
including random selection of which bumps they
soil. Tell them that they will look closely at the


Use: 0.4893