What are biological indicators? Why are macroinvertebrates good indicators of water quality? Objective Students will: - Be able to successfully identify macroinvertebrates using a dichotomous key. - Understand how macroinvertebrates are important indicators of water quality. Preparation Instructor should review the presentation, accompanying dichotomous key(s) and "Life on the James" activity before instruction. Total preparation time: about 60 minutes. Procedure Opening questions (5 minutes) Introduction to macroinvertebrate identification (25 minutes) Dichotomous key practice (10 minutes) “L Duration: 90 Minutes.