To activate my students' shared prior knowledge, I begin this lesson with a review of the Benthic Macroinvertebrate Exit Ticket that the students completed in the first lesson in the macroinvertebrate unit. It is important that students be able to define a macroinvertebrate and describe their defining characteristics. Reviewing their previous exit ticket allows students to reengage with their learning about macroinvertebrates.
To introduce students to the macroinvertebrates they will see in our future field studies, I split the macroinvertebrates into two groups. I spend one lesson focusing on each group of macroinvertebrates. In this lesson, I introduce the first group of macroinvertebrates to students using the macroinvertebrate identification power point presentation. All macroinvertebrates in this group are pollution sensitive, meaning that they can only live in cool, clean water free from major pollution. This fact is key as the presence or absence of pollution sensitive macroinvertebrates tellls us much about water quality.
I begin the lesson by introducing the two new vocabulary words; pollution-sensitive and bioindicator species. I write these on the board and guide students to come up with a definition for each term. Then, using the power point presentation, I show the students one macroinvertebrate's picture and identifying features. I model how to record the information on the macroinvertebrate identification chart. Next, I provide students with time to draw and color the species on their chart. I repeat this process for all pollution-sensitive macroinvertebrates. A sample of a student's completed chart shows the illustrations and definitions for all pollution-sensitive macroinvertebrates.
To aid students in remembering the key feature of the three most common pollution-sensitive macroinvertebrates, I show students a gesture to represent the mayfly, stonefly, and caddisfly. A video demonstration of the gestures can be found here.
I close the lesson by providing students with time to share their work on the macroinvertebrate identification chart with a peer partner. I encourage students to share their drawings and descriptions of each macroinvertebrate with their partner and to modify or add to their chart if they feel that their partner captured an important idea or detail that they did not. Summarizing their learning is an instructional strategy that aids students in remembering key concepts and connecting their new learning to their prior knowledge.