Question: How many kinds of mushrooms can you find, and do some appear to be associated with particular kinds of green plants?
NOTE: STUDENTS MUST BE CAUTIONED NOT TO EAT ANY MUSHROOM or parts thereof, and as with all outdoor activities, TO WASH HANDS CAREFULLY AFTER THE ACTIVITY.
How To Do It: After a rainy week in any season, class hunts around the edge of the schoolyard seeking mushrooms. This should work in any schoolyard with a brushy or woody edge. Students examine mushrooms carefully, looking for spores, looking for larval or adult insects in the mushroom, and, most important, trying to figure out what plant (usually a tree, sometimes a shrub or perennial herb) the mushroom is associated with. After all, no mushroom is an island—all are sporophytes of fungi associated with living (usually) or dead plants (see field guide entry). If there’s time and interest, this can be done best by digging with the fingers at the base of the mushroom, locating the root that is nearest, and tracing the root to the tree or whatever to which the root belongs.
Discussion: What is a mushroom? What is its place in the fungal life cycle? What’s it doing associated with a live plant? What benefit does the fungus get from the plant? What benefit does the plant get from the fungus? Are different mushrooms associated with different plants? Why might this be so? Or are some apparently associated between plants of different species? Might fungi serve as a “living bridge” between different trees of different kinds? Why are fungi often poisonous? Why put the energy into producing a poison? Is it foolproof? What are those insects doing inside the mushroom? Might they be damaging it? On the other hand, might some insects inadvertently benefit the fungus? How? Might spores stick to their bodies? How else might animals inadvertently benefit fungal spores? What if mice and flying squirrels were to eat mushrooms (they often do, without poisoning themselves) and then were to defecate elsewhere? etc. etc. Lots of mushroom questions, but the most fun part is just the mushroom hunt.
Framework: 7.a. (actually, a topic not on the outline).
79. Fungal Succession on Pineapple.
Question: What happens to pineapple (or other food) when it’s kept for too long?
Needed: Some sort of canned fruit or other soupy food that someone has kept for too long in the refrigerator (or out of the refrigerator). Ask students to ask their moms not to throw out last week’s bowl of rotting fruit etc., as long as there is obvious “mold” starting to grow on it. On the other hand, teacher can exert some control over the situation by buying (a) a small can of pineapple; (b) a small can of applesauce; © one banana; (d) a potato, and four small refrigerator dishes with snap-top lids.
How To Do It: Cut the potato in half; peel the banana; open the cans; put each substance in a different refrigerator dish and let stand uncovered (on counter, not in refrigerator) overnight. The next morning, sprinkle a bit of water on the banana and on the potato, then close the lids. Leave dishes on counter, out of direct sunlight, at room temperature. Check every day for signs of fungus. Have students draw a “map” of each of the glops of food, and run these off on the mimeo so that there are lots of copies. As soon as the first mold (fungus) appears, have students “map” the extent of the colony (ies) daily. Use a different color code for each kind of fungus on each of the four foodstuffs. Plot the course of fungal colonization, colony growth, dieoff or overgrowth (by another species) until the mess has completely dried up or until you can’t stand it any more. Look at what you have.
Discussion: Do the first molds to “colonize” the food persist all the way through? Or are they replaced by other kinds? Why might this be so? Could it be because the first colonists actually change the nature of the food, rendering it less fit for themselves but more suitable for other kinds of mold? or are the later colonists competitive superiors, capable of destroying (through overgrowth or poison) the first colonists? or do the first colonists simply have short but merry lives. whereas the later “colonists” are more sober, slower growing kinds? What’s going on, anyway? Do you think there are interactions between different fungi? Ever hear of antibiotics? Where were they first discovered? Might not one kind of mold secrete a kind of chemical that kills off other kinds of mold (and other decomposing organisms), thus saving the food for itself? Do you see any evidence? Looking at the maps, do you see one colony of one kind “encroaching” on a colony of another kind, and the latter shrinking from the contact? Would it be of any benefit to molds (and other decomposers) to make their food “stink” and “taste/look/smell yucky” to you or other potential consumers? What would happen if you were weird and liked to eat moldy food (and weren’t poisoned by it)? what would happen to all those poor little fungi? So is there some survival value to fungi (and other decomposers) in making the foods they have colonized “yucky” to larger consumers? Forgetting this last part: can you think of any examples around the schoolyard of a situation where there is a time sequence of plant (and animal) species on a site, with some coming in quickly and others coming in later? What are the similarities and differences between fungal “succession” and plant succession? etc. How would you test all of the hypotheses you’ve come up with? Are the first colonists of the different foods the same or different? Are the later arrivals the same or different? Might the first colonists be “generalists” and the later arrivals be “specialists” (or the other way around)? etc. etc. etc.
Season: A (best done indoors).
Framework: 7a (3b. 4d, 8a, 13).
Question: Does the efficiency of scavengers vary with habitat, and why?
Season: F,S (W).
Background Information: Note the importance of scavengers (and decomposers) in our world. Without them, the world would long since have been buried under a pile of dead animals and plants. Some human activities are rough on scavengers, though, and some habitats have less than their share. Let’s find out.
Needed: One hot dog; one small piece of fresh liver; one slice of mild cheddar cheese (no processed cheese, please—too salty); recently dead houseflies if available; microscope slides or small slide-sized pieces of cardboard.
How To Do It: Students decide on schoolyard habitats among which they want to compare scavenger efficiency. They come up with a prediction of what habitat will have the highest scavenger efficiency, which habitat the least (and thus the most potential to accumulate stinking decaying matter). They will scatter 5 slides or cardboard pieces (replicates) in each habitat. Cut liver, cheese, and hotdog into tiny pieces (cubes about 3 mm on a side), so that there will be one piece of each for each slide. Pieces cannot be any larger or they will attract cats or dogs instead of the smaller scavengers of interest. On each slide are spaced out one representative of each food item (3 or, if the hoped-for houseflies are available, 4). Put the slides out at the end of one school day and check early in the morning of the next. Compare results between habitats.
Discussion: In which habitat were scavengers the most efficient? the least efficient? Why might this be so? What habitat has the most cover for scavengers? the least cover? Which has the most inimical microclimate for scavengers? the most mellow? In which would human disturbance have messed up scavengers the most? What do you think the scavengers are? If few pieces have been removed by morning, the slides can stay out throughout the following day, and students can check them whenever the teacher permits, not only for removal but also for who’s doing the removal. Are ants responsible? what else? Hopefully one of the habitats chosen will have been the most complex (vegetationally), woodsy area of the schoolyard. Is dead material recycled most rapidly in the most undisturbed and complex habitat? Is dead material most likely to accumulate and stink/rot in the most highly modified habitat? What are some implications to human activity? etc. etc.
81. Wanted: Soil, Dead or Alive
Question: What living things are, or have been, in soil?
Framework: 11 (2.a., 13).
Needed: hand lenses, toothpicks, baggies.
How To Do It: Teacher collects samples of soil (only 1 cup is needed, but more is OK) from various schoolyard habitats, and labels each sample with a number; teacher makes independent description of the habitat/microhabitat from which soil was taken, and keeps this secret from students. Try to keep samples intact, so that top layer remains distinct. Wrap each soil sample securely in aluminum foil.
Students divide into small groups (2-3). Turn out the lights while teacher passes hand-lenses and toothpicks to each student and a soil sample to each group. Tell students that they are extraterrestrial beings, and that they must analyze a sample of the surface of a distant planet. The sample has been collected by a voyaging spaceship that has just returned. Tell students that this is the only material they will have to determine whether or not there is life on the mystery planet. Their mission is to study the sample, collecting evidence for life (or lack thereof). If possible, they should use their imagination to extrapolate from the evidence compiled to a proposed environment from which the sample was taken. Turn on the lights and emphasize that they must open the packets carefully to preserve their fragile structure. Have students enter a description of each fragment of evidence into a logbook, numbering each entry. Have them collect the material evidence in Baggies, numbering each according to the entry describing it. Have them pool their research effort by writing a few sentences summarizing their evidence and drawing conclusions about the habitat. Go through their results, showing all of the class the notable discoveries and reading the written summary. For each soil sample, then tell the students where it came from, and compare the students’ extrapolated description to the actual description.
Discussion: Discuss the differences between things that are alive, have once been alive, or things that show no evidence of having been part of a living organism.
82. Plant Chemistry
Question: Do different plants have different chemistries, and why?
Season: SF (W).
Needed: blindfolds for about 50% of the students; Sharpies for marking leaves.
How To Do It: Teacher collects samples of a variety of leaves, testing eah to be sure it has a noticeable and distinct aroma. Good candidates are citrus, bay, carrot, mustard, bean-family, dogwood, pine, juniper. Divide the class into half. Pass out several leaves of several different plantts to one half of the students, blindfolds to the other half. Pair the students, and have each pair number every leaf and then classify the leaves according to shape, marking a particular letter on each leaf of one type. Blindfold one student in each pair. Have the other students break off a small, unmarked portion of each leaf and present it to the nose of the blindfolded student, comparing two leaves together (same or different) until all are categorized. Record the results.
Discussion: Compare the classification by smell and sight. Was it easier to classify the plants by smell, or by sight? If you were an herbivore able
to feed on only a few plant kinds, how might you identify the right plant?
83. Layers of Butterflies.
Question: Do different butterflies occur at different heights above ground, and why?
Season: F (S).
Framework: 8a (5a, 5e. 2a).
Needed: meter sticks.
How To Do It: Find a fairly butterfly-rich part of school grounds (weedy hedge or woods edge might work), on a warm sunny day. Students simply search for butterflies (resting, feeding, or flying) and guesstimate the height above ground, using the meter stick—to the nearest 10 cm for butterflies under 1 m, to the closest 1 m for higher ones. Continue for at least 20 minutes. Then make a “tally chart” of the distribution of butterflies of each kind (students do not have to classify formally, just recognize different kinds) against height above ground, like the following:
Type of Butterfly
a b c d e f
Discussion: Now comes the fun part. Sitting around outside, students try to figure out why different butterflies are at different heights, and for every idea proposed students must come up with a way of testing it. Some of the ideas are:
(1) Butterflies at different heights get to use different sets of flowers for their nectar food. Any evidence?
(2) Female butterflies fly at the heights where the plants on which they lay their eggs occur; thus, males fly at those heights too. Any evidence?
(3) Butterflies “trying not to be seen,” i.e., cryptically colored butterflies, cling close to the ground; brightly colored butterflies, “not afraid” of advertising their presence to potential predators, fly out in the open or up in the air.
(4) Small butterflies fly close to the ground where the wind won’t mess them up; large, strong butterflies don’t care, so fly anywhere they damn well please.
(5) What else? let students come up with ideas and suggestions for testing these ideas.
84. Rock Pets
Question: Is there any pattern to what arthropods live under rocks; in particular, do ants show a “checkerboard” distribution under rocks?
Needed: This activity works ONLY when the school grounds have several dozen ROCKS (a rarity in Florida), old shingles, old boards, or whatever that have been lying on the ground for a long time. The ideal schoolyard would have a number of rocks ca. 6-12 inches across partially embedded in the soil; or a number of old shingles tossed every which way at least 6 months earlier.
Background Information: This pattern suggests that competition may be responsible for an evened-out distribution.
How To Do It: Given the above unlikely events: Students make a “map” of the locations of rocks. Then they turn over rocks and note what ants are underneath: what kinds, and how many kinds. Teacher co-ordinates nomenclature among different students or groups (“tiny fast black ant, big red-brown ant, etc.”). At the end, label each rock on the map with the kind(s) of ant underneath.
Discussion: Questions to keep in mind, and to discuss at end, are: how many kinds of ants total occur under rocks? how many kinds occur under a single given rock? How are the different species distributed? Are they like a “checkerboard,” for example with 10 rocks having ants A, then B, then A, then A, then B, then A, . . . but never both? How might you explain the distribution you find? Do ants eat one another? Might they eat the same things? Might they simply be aggressive towards one another, whatever the cause? How does this finding relate to the distribution of other kinds of plants and animals? etc. etc.
85. First Come, First Served?
Question: How do different ant species deal with food discoveries and with other ants who discover the same food?
Note: So many concepts are embodied in this activity that it might be good to split it into 2, or even 3, separate activities—up to you—but it does work, especially in sandy schoolyard margins.
Framework: 8a (3.c.ii).
Needed: strips of cardboard (not corrugated cardboard, just stiff cardboard like that on the back of a notepad), and a small amount of each of the following: cheap tunafish (in oil); saltine crackers; cooking oil; not-too-ripe banana; honey. Cardboard strips should be about 15 cm x 3 cm (6” x 1”), and there should be one for each two students.
How To Do It: Each strip gets a small dollop of each food item: a little pile of tuna, a little pile of cracker crumbs, a few drops of cooking oil, a slice of banana, a little mound of honey, all arranged in a row and none touching another. Students take strips to the chosen habitat (I suggest the sandy border of a schoolyard, near the lawn but also near weedy scrub), and each pair gets to choose a location for their strip (but make sure they remain in basically the same habitat—otherwise this turns into another scavenger hunt). It’s best to do this on a fairly to very warm day when ants are active. Anyway, just watch and record observations: what ants arrive first, how many arrive at once, what happens next (does the scout go running back to the nest, and how many colleagues does she bring with her?), how many kinds of food does the first kind of ant exploit, who comes next, how do they recruit, do they beat up on the early ants, do they try as many different kinds of food? Students do not have to identify ants by name; they just have to distinguish different kinds, and keep these straight. Students who are getting little or no action should be allowed/encouraged to abandon their worthless strips and to converge on the action centers, because I guarantee (almost) that some students will have very active “food strips.”
Discussion: The following should be considered: are the first ants to arrive smaller than the later ones? do they get beat up by the later ones? do they have broader diets? do they even bother recruiting help, or do they just scram with what they can carry? do the later arriving ants have good recruitment? do they arrive in a big gang? are they more particular in the food they choose? which food do they choose? how can different ant species eating the same foods coexist? what would happen if the order of discovery were reversed, that is, the current first-come-first-served ant were slower than the other? would coexistence occur? so, what can you say about the relationship between the following: speed at discovering food, generalized vs. specialized diet, recruiting, and behavioral dominance? can you think of any other situations where “fast wimps” and “slow bullies” coexist and exploit similar resources? etc. etc.
86. Spider Specialists.
Question: Are webs of different spider species designed to catch prey of different sizes, and why?
Framework: 8a (3.c.ii).
Needed: Insect nets (bought or home-made from cheesecloth, stiff wire, and dowel).
How To Do It: Search schoolyard-edge vegetation for spider webs of 2 or more species. Most schoolyards will have webs of several different sizes and inter-strand distances. Choose 2 or at most 3 of the most distinct interstrand differences (ideal would be orchard-spider [Leucage] webs, golden-orb-weaver [Argiope] webs, banana-spider [Nephila] webs). Measure interstrand distances (in mm) on a few webs (again, measure interstrand distance halfway between the center and the edge of the orb). Then measure the length of prey, if any, that have been caught. Is there a relation between interstrand distance and size of prey? Now, with insect nets sweep through vegetation and see what you can get. Try tossing insects of different sizes/ shapes/ jumpinesses into the different webs. Which insects pass right through which webs without touching a strand? Which insects rip through which webs? Which insects bounce off which webs? Which insects are caught by which webs? A better trick yet would be to have a fruit fly culture and a housefly (or stablefly) culture, and to release flies of these two radically different sizes near the webs.
Discussion: So, are large interstrand distances (and tough webs) effective at catching large insects? are small interstrand differences (and nearly invisible, filmy webs) better at catching small insects? why don’t spiders spin webs effective at catching all insects? does this mean that different kinds of spiders end up catching different prey? why are there these differences? Do spiders spin different webs “to avoid competition”? Do you really think that the spiders are competing with one another—are insects so scarce that building a web that captures different prey from other spiders is really important? or is each spider simply specialized for a particular kind of prey for efficiency reasons? in which habitat would more different kinds of harmfall insects be consumed, taken out of circulation, by spiders: a habitat with one numerous spider species, or a habitat with several different spider species? that is, what effect does a diversity of spiders (and webs) have on their prey? etc. etc.
Question: Do plants inhibit the germination of one another’s seeds?
Framework: 8a (4c).
Needed: Paper towels; packets of lettuce and radish seeds; mortar and pestle, or something to grind leaves; bowl. Covered plastic Petri plates would be great but are not absolutely necessary.
How To Do It: Soak lettuce or radish seeds in plain water, in bowls, overnight. The next day, send students out collecting leaves from 4-8 different kinds of common schoolyard shrubs/trees. Use some guidance: best possibilities are wax myrtle, cherry laurel, bay, magnolia. Do not use conifers or oak. Each kind of leaf should be ground up, in a little water, in the mortar and pestle or whatever. Soak the paper towel, fold in half (if not pre-folded), and place either on windowsill or (better) after appropriately folded, in plastic Petri dishes kept on windowsill. Sandwiched inside each “and”) lettuce seeds. Leave some as is (controls). Underneath others, on top of another wet paper towel, place a reasonably sized dollop of one kind of wet leaf mush. Have at least 2 replicates of each kind of leaf mush. Towels must be kept constantly damp. Simply note the speed of germination of the seeds under the different treatments.