Decomposers Lesson 1 Background Information

Three-dimensional Learning Progression

The pretest and discussion in this lesson (a) help students to anticipate and begin thinking about the questions that they will answer in this lesson and (b) help you as a teacher see how your students’ reason about how matter and energy are transformed when things decay (digestion, biosynthesis, and cellular respiration in decomposers). In the Application Activity Sequence, both Activity 1.1 and Activity 1.2 in this lesson serve as the “Establish the Problem” phase for all the activities in the Decomposers unit.

Key Ideas and Practices for Each Activity

In Activity 1.1, the unit pretest is useful for two purposes. Your students’ responses will help you decide how much detail you want to include during the unit, particularly details about chemical structures of materials. If your students are mostly at Level 2 in the carbon learning progression, you may want to focus on the main ideas (like the tracing of matter and energy and the Three Questions) rather than chemical structures. Your students’ responses will also provide a starting point for discussions about the focus for this unit.

In Activity 1.2, through the discussion students will come to recognize that they have many different ideas about what happens when bread molds, as well as unanswered questions. We expect many students to express Level 2 or Level 3 ideas, for example, that decomposers grow because their cells divide, or that gas has no mass, or that decay is not related to decomposers.

Key Carbon-Transforming Processes: Digestion, Biosynthesis, and Cellular Respiration

Content Boundaries and Extensions