My Science Box

Sources
Bottle Biology contains everything you wanted to know about terraqua columns.

Standards
Grade 6
Ecology (Life Sciences)

Summary
Once students have some experience working with a basic terraqua column (see the Terraqua Columns Lesson), they have an opportunity to design and conduct their own investigations with their mini-ecosystems. There are hundreds of variables students can manipulate with a minimum of materials – temperature, light, pollution, type of water, type of soil, etc. As a class, students brainstorm variables that might affect the plants, soil, and/or water in a terraqua column. In teams, students propose a project, and once approved, set about testing their ideas and observing the effects of their manipulations on their mini-ecosystem. If your school participates in a local science fair, this is a fantastic activity to introduce students to experimental design, variables, and control groups.

Sources
The idea for this activity came from a workshop by Karen Kalamuck at the Exploratorium. THANK YOU Karen!

Going Further
Another cool termite trick… Did you know that termites mistake the smell of a Bic pen for a pheromone that they use to navigate? Pheromones are chemicals that communicates a message to other members of the same species. Although humans do have pheromones, termites and other social insects communicate extensively through these chemical messages. Termite workers indicate the path to a food source by leaving behind a trail-pheromone. A chemical in Bic pens (not other pens for some reason) mimics the trail-pheromone. If you draw a line with a Bic pen on paper then place a termite on the line, the termite will faithfully follow the line wherever it leads. Try drawing curly-Qs and other shapes. See what happens when a termite hits a crossroads. Try pens by other manufacturers. Try different colors of Bic pen.

Lesson Plan

1. It’s pretty useless trying to hold the kids attention when there are moss and mushroom covered logs on the tables. Thus, give the students the question sheet right away and let them go once you read the rules:
2. Use any of the tools provided.
3. Don’t harm any organisms.
4. You may carefully break small pieces of the log apart but NO SMASHING. Keep all the pieces of the log in the basin, NOT all over the table or the floor.
5. Have students answer the questions in a lab notebook or on a separate sheet of paper. The questions are on the student Rotten Log Questions download but are also listed again here for your convenience:

• List as many organisms in the ecosystem as you can find. For each organism, draw a picture and label it with a name that describes the organism like “light-brown, long bodied ant-like thing” or “2 cm-long black beetle”. More things are living than you might think…
• List as many non-living parts of the environment as you can find. There is more than just wood – think about solids, liquids AND gases!
• Which of the things you just listed are part of the log community?
• Which of the things you just listed are part of the log ecosystem?
• What is the difference between a community and an ecosystem?
• Find evidence about the food webs that make up the community. Do you see any organisms eating? Do you see any “poop” that gives a hint about what the organisms have been eating? Draw as much of the food web as you can.
• Describe one organism-organism interaction that you observe.
• Describe one organism-environment interaction that you observe.
• How will this lab impact the populations of organisms in your log? Pick one organism and describe how the population of this species will be affected by our investigation.
• Is this ecosystem sustainable? Why or why not? Use your observations to support your idea.
• If you have a protozoa viewing station set up, invite groups one at a time to come visit you at the microscope to see the protozoa.
• Reserve plenty of time to clean up.

Getting Ready

1. Find some nice, juicy, moss and mushroom covered, termite and beetle infested logs. You know you’ve found a good log if you can pull off chunks of wood with your hands. I discovered mine (8 logs, enough for my students in groups of 4) in a wooded area of Golden Gate Park. You can use the same log with 2 successive groups of students if you just make sure the first group doesn’t go crazy with the hammer. You can also flip the log over for the second group. I found that the best time to go log hunting is after a month of nice, wet weather after mushrooms have begun to appear.
2. Make copies of the Rotten Log Questions
3. Cover your tables with newspaper
4. Set out logs and the group materials

Teacher Background
I used this activity as a lab-based test that the kids didn’t actually think was a test. It was a super way for them to reveal the holes in their understanding before the written test. Some of the major concepts that can be assessed in this lab include differentiating between a community and an ecosystem, creating food webs, identifying interactions between organisms and between organisms and their environment, predicting the effects of human impact on populations, and assessing ecosystem sustainability.

Time
45-55 minutes

Grouping
Groups of 4-6 students per log

Materials
For each student:

• Copy of the Rotten Log Questions

For each group of students:

• 1 rotting log, preferably with lots of mushrooms, moss, fungi, termites, beetles and other creepy crawlies in and around the log
• 1 large plastic wash basin or large heavy duty yard waste trash bag to keep the log in
• Work gloves
• Screwdriver, shovel, pry bar, hammer or other tools that can be used to pry open sections of the log
• Bug boxes
• Newspaper to cover the tables

Summary
This is an alternative assessment activity in which students pull apart a rotting log as an example of a microhabitat that can be explored in the classroom. As they dissect the log and discover the myriad of bizarre creatures on and inside the log, the notes the students keep can be used as an assessment of many of the major concepts in this unit. Another use for this lab is as an engaging way introduce a very special organism-organism relationship, symbiosis. Termites have a symbiotic relationship with the protozoa in their gut. The protozoa that digest the cellulose in the wood for the termites, can be extracted from the termites’ gut and observed under a microscope. One of my students who witnessed the extraction and then saw the protozoa proclaimed “That was the coolest thing I have ever seen. Ever.” Finally, if you are just fascinated by termites and want to become completely enamoured, try putting a termite on a line drawn by a Bic pen…

Summary
At the end of the unit, students can now apply their understanding of ecosystems, food webs, resource management, native vs. nonnative species, and human environmental impact to a real world situation. Individuals involved in habitat restoration routinely research and select plants and animals to include in a redesigned ecosystem. In this final project, students will create posters with a minimum of 8 native plants and 5 native animals that should be included in the redesign of the habitat they surveyed previously. They will look at how these organisms will interact and discuss how to sustain the ecosystem into the future. If it is possible to do a long term habitat restoration near your school, this is an excellent exercise to get the students personally invested in the restoration work because they played a role in selecting the species they will reintroduce.