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Objectives: Students will create their own complete ecosystems and select the best bioindicator for their system.
Time needed: 3 class periods for the Engage, Explore and Explain. Elaborate should be done over the course of the school year for a full understanding of the organisms and their relationships.
Materials needed: Art supplies, access to an outdoor environment, monitoring lesson plans
Best season: Any
Background information: This lesson would act as a good "evaluate" component of a lesson on the structure of ecosystems.
Engage: "Little Worlds" activity. Hand out art supplies: paper, pens, collage materials. The assignment is to create an artistic representation of a "little world:" a simple, sustainable, self-contained ecosystem with organisms and non-living things that interact. This little world can be anything that the students want to represent (i.e. a fictional ecosystem on a distant planet, a depiction of the ecosystem in a pet's hair, the ecosystem in one's tennis shoe, etc). Creatures and abiotic factors can be real or imagined, but the students should be able to describe, with as much detail as possible, the relationships between these factors and the environment. There should be demonstrations of symbiotic relationships in the little world. Students use art supplies to create their little world, and write a 1-page paper describing the relationships depicted within. If you must, send the students home with their activity to finish it and be able to discuss it in the next class meeting.
Explore: Students are given the opportunity to share their little worlds with their peers. As the students share their work, jot down important vocabulary on the board, as well as concepts that arise: symbiosis, trophic categories, limiting factors, etc.
If there are gaps in the ecosystem represented in their little world, give the students a chance to make it more complete.
When the little worlds are complete, ask the question:
HOW WOULD YOU KNOW IF YOUR LITTLE WORLD IS HEALTHY?
Write student ideas on the board as they come up with them. It is likely that one of the students will volunteer the definition of a bioindicator, though they might not know the term. Look for references to looking at populations of one species in the little world to understand how of well the whole ecosystem is functioning. When this is described, let the students know what a big "Aha" that is, and give them the term "Bioindicator." Which leads to another question:
WHAT MAKES A GOOD BIOINDICATOR?
Again, have students brainstorm some answers to the question, and write down what they say. They should come up with a list of qualities that would be important in a bioindicator (hopefully these qualities match the list in the background information). Do the following comparison activity: Have the students take out a blank sheet of paper and draw a line down the center of the page (so there are two columns). Have each student select one critter from their little world to serve as a bioindicator and write it at the very top of the page. In the left column, have the students copy the list of qualities that they just generated. In the right column, they should write down whether or not they think their critter meets the criteria in the left column. Once completed, bring the students back to discuss as a group.
Explain: Hand out the article, wherein students check their chosen bioindicators against Pearson's criteria. Have them read the article and then look back at their little world. After looking at all of the criteria and the different inhabitants of their little world, students decide the best bioindicator for the health of their little world. Is their current choice of bioindicator the same as the one they selected in the Explore section? The students write a paragraph describing and justifying their choice, speaking to each of the bioindicator criteria.
Elaborate: Break the students in to working groups and assign a real ecosystem to each group. The ecosystems you assign should have some relevance to the students, using nearby indoor and outdoor resources. Some teachers assign quads of the school grounds to their students, others have access to off-campus resources. Use what is convenient for you. If all you have is the school janitor's closet...that's still a learning opportunity! Students should spend some time in their ecosystem, learning what lives within it. They can employ several techniques to create an inventory of organisms within their ecosystem: bird point counts, water quality monitoring, etc. A Wetland Assessment lesson plan is available from HWI, but there are also many other materials available through resources such as Flying WILD, Project WET, etc.
Evaluate: Have the students write a 2-minute message at several key points throughout the school year: once after completing the Explain portion of the lesson, once after a single visit to their real ecosystem, and once after several visits to their real ecosystem. Track how student understanding changes over time and experience.
