WHAT MAKES US TICK…TOCK?: USING FRUIT FLIES TO STUDY CIRCADIAN RHYTHMS.

Teachers often ask: How can I engage my students in the study of “real” science? The answer can be found in the National Research Council’s A Framework for K–12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (NRC 2012). This framework calls for a new approach to science education and is the basis for the Next Generation Science Standards (NGSS) (NGSS Lead States 2013). It emphasizes the need for stronger collaboration within the scientific community to develop curricula that address the core ideas, scientific practices, and crosscutting concepts for all students. Project NEURON has developed a curriculum unit titled, “What makes me tick … tock? Circadian rhythms, genetics, and health,” that combines scientific practices identified in the Framework and NGSS (Figure 1, p. 38); core biological ideas, such as Genetics and Animal Behavior; and crosscutting concepts, including Cause and Effect, Structure and Function, and System Models. Unit materials are available free online (see “On the web”).

This article gives an overview of the unit, then describes in detail one of its eight lessons. FIGURE 1 Alignment with the Next Generation Science Standards. These lessons align with the following NGSS, among others. HS-LS3 Heredity: Inheritance and Variation of Traits Performance Expectations Students who demonstrate understanding can: HS-LS1-1. Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells. HS-LS3-1: Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

Common Core State Standards Connections: ELA/Literacy: RST.11-12.1 Cite specific textual evidence to support analysis of science and technical texts, attending to important distinctions the author makes and to any gaps or inconsistencies in the account. (HS-LS1-1, HS-LS3-1) WHST.9-12.2 Write informative/explanatory texts, including the narration of historical events, scientific procedures/experiments, or technical processes. (HS-LS1-1) WHST.9-12.9 Draw evidence from informational texts to support analysis, reflection, and research. (HS-LS-1-1) RST.11-12.9 Synthesize information from a range of sources (e.g., texts, experiments, simulations) into a coherent understanding of a process, phenomenon, or concept, resolving conflicting information when possible. (HS-LS3-1) ADAPTED FROM NGSS, PAGES 89 AND 93 (NGSS LEAD STATES 2013) Unit overview The first lesson asks students to draw connections between the science of circadian rhythms and their own lives. The stu dents discuss how their behavior and moods can be affected by their sleep-wake cycle. In Lesson 2, students focus on how environment and genetic mutations can affect the sleep-wake cycle. In Lessons 3 and 4, they investigate how specific genetic mutations can lead to physiological and behavioral changes. In Lesson 5, students investigate light intensity in their schools and ponder how humans’ exposure to light can affect circadian rhythms. In Lesson 6, students examine conditions that can disrupt humans’ circadian rhythms and then report on the dangers of this phenomenon. In Lesson 7, students explore epigenetics and how environment and lifestyle choices can influence not only their own circadian rhythms but also their offspring’s rhythms. Finally, in Lesson 8, students create a proposal for school administrators that makes a case for when the school day should begin. The students use their findings from the unit’s activities as evidence and reasoning to back up their proposal. Figure 2 (p. 39) provides an overview of the “What makes me tick … tock?”