Macro Mayhem

Essential Question
How does the phrase "appearances can be deceiving" apply to the water quality of a sparkling, crystal blue stream?

Students play a game of tag to simulate the effects of environmental stressors on macroinvertebrate populations.

Objectives

 * illustrate how tolerance to water quality conditions varies among macroinvertebrate organisms
 * explain how population diversity provides insight into the health of an organism

Vocabulary

 * macroinvertebrate
 * biodiversity

Materials

 * identification labels for macroinvertebrate groups, one per student
 * pillowcases or burlap bags
 * chart paper or a chalkboard
 * samples of macroinvertebrate organisms

How it Fits to Standard

 * Structures and Behaviors (4-5): Plants and animals have different structures that meet their needs and respond to the environment.
 * Changes in Ecosystem (2-3): Changes in ecosystems affect living populations and the non-living elements of a defined area
 * Classifying Plants and Animals (K-1): Both plants and animals have different characteristics that can be used to classify them.

Follow Up
Discuss the outcome with students. Emphasize the changes in the distribution of organisms among groups. Have students compare population sizes of groups at the beginning and end of the game and provide reasons for the changes. Review why some organisms are more tolerant of poor environmental conditions than others. Have students compare the stream environment at the beginning of the game to the environment at the end.

Have students investigate a nearby stream. What kind of macroinvertebrates live there? How would students describe the diversity of organisms? Do students' findings provide insight into the quality of the stream? What other observations can students make to determine stream quality?