The Macroinvertebrates simulation gives students an introduction to the practice of using macroinvertebrates to monitor the quality of a freshwater ecosystem. The term macroinvertebrate includes animals without backbones that are large enough to see without a microscope. Worms, insects, and crustaceans are all examples of macroinvertebrates. This simulation uses twelve different animals.
The simulation has two river ecosystems and macroinvertebrates can be collected from each of these separately. Each time the user clicks on the "Click here to collect macroinvertebrates" area, a sampling of organisms will appear in the collection tray. At this point students can count the organisms and record their data. They can continue to collect to increase their sample size. As with most simulations on this site there is a randomized component so each student/group will get slightly different data from the activity.
There are two main ways this simulation can be used. First, it can be used to practice quantifying biodiversity using a variety of methods, such as Simpson's Diversity Index. This simulation can be used as a freshwater alternative to the forest setting of the Biodiversity simulation. A worksheet is provided that utilizes Simpson's Diversity Index.
Second, Macroinvertebrates can simulate a river quality study using macroinvertebrates as bioindicators. Bioindicators are species that can be used to assess the status of an ecosystem. The worksheet that accompanies this simulation walks students through a fairly simple river quality analysis. While actual field studies often involve slightly more complicated and diverse metrics, this activity gives students an introduction to the process. This simulation can stand on its own as an in-class activity, or it can be used to introduce the process before doing an actual assessment in the field.
In the river assessment activity, students will identify the organisms collected by groups. Group I is pollution sensitive, Group II is somewhat pollution tolerant, and Group III is pollution tolerant. As pollution in the environment increases the proportion of pollution tolerant species in the environment will increase, which is why this method can be used to assess and compare water quality. To perform the analysis students will need to find percents and use a chart to assign values to each group.