Primary Source Exemplar: Nutrition and Human Rights
Overview
In this lesson, students will begin to answer these questions, first by gathering information about their own diets and them by relating that information to ecological data. Students create a visual journal of what types of foods they consume over a period of two days, use their meal journal to make a food web and track the transfer of energy that began with producers, including mathematical computations of energy transferred and energy lost, and analyze a national study on food consumption, “Foods Commonly Eaten in the United States,” to determine if their diet over two days is similar to the average U.S. diet over two days. Students finish by writing a claim about the efficiency of their own diet and that of the average American that is supported by ecological efficiency data from their food web.
Learning Objectives
The student will be able to analyze efficiencies of diets by tracking energy transfer.
Sub-objectives
Explain what a primary source is and how primary sources can be used in biological studies.
Students will be able to determine over-arching trends in human diet by analyzing a national study.
Students will be able to evaluate the effectiveness of their diet by comparing data from their own food survey to data from a national study.
Students will be able to evaluate the efficiency of their diet by tracking the transfer of energy.
Students will be able to evaluate the claim “The average human diet is meeting nutritional needs.”
Standards Addressed
CCSS R-2 Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions.
CCSS R-7 Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).
CCSS W-1 Write arguments focused on discipline-specific content.
HS-LS2-3 Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.
Instructional Approach
Introduce the Lesson
Introduce the students to the idea of keeping a journal of their diet by asking them to quickly think of all the different types of food they ate in the last two days. Can they remember? Explain to the students that they will be writing down exactly what they consume over two days. Students might use technology to take pictures of the consumed food, use a journal to record type and portion size of meals or be given a data set of a pre-determined diet. Be sure to ask students to carefully record the amounts of each type of food they eat. Provide an example of how to determine how much of each product they eat. Most packaged foods come with serving size information, which can be used to determine roughly how much the student consumes.
Model and Demonstrate Desired Learning
1. Support students’ understanding of the concept of energy transfer by asking probing questions such as “Where did that food source come from?” This question guides students to determine that the original food sources are producers and the original energy source is the sun.
2. After allowing students to make discoveries, provide direct instruction on the classification of food as proteins, carbohydrates and lipids, the hierarchical arrangement of food webs and the 10% energy transfer rule. Model how to determine the energy transfer for several types of foods, the amount of energy transferred and lost, and whether or not certain foods are efficient in this process.
3. Now, guide students to use their meal journal to make a food web and track the transfer of energy that began with producers, including mathematical computations of energy transferred and energy lost.
4. Explain to students that in this unit they will be using a variety of information from primary sources (text, tables, graphs, etc.) to study an important question about the world’s population and human rights. Have students share (first in pairs, then as a class) what they know about what a primary source is. Present them with a definition of a primary source, such as the one below, and have them annotate the definition for key words that might be related to mathematical study:
Primary sources include observations, data, artifacts, first hand accounts, records and evidence collected from witnesses, scientists, and others, that convey information about the natural and social world. Examples of such sources are: informative or explanatory texts, scientific literature, specimens, data sets, oral histories, autobiographies, memoirs, opinion pieces, journalistic accounts, photographs, maps, realia, graphs, documents, charts, and speeches in various media and formats.
5. Introduce the text from the U.S. Department of Agriculture titled, “Foods Commonly Eaten in the United States.” Students will analyze the data provided in this document to determine if their diet over two days is similar to the average U.S. diet over two days. Begin analysis of the data by asking students to search for specific details by asking guiding questions such as:
What kind of information is shown in the document? How is it organized?
What words, phrases, or concepts do I need to know to better understand what the document is communicating to me?
How often and how much do people eat macaroni and cheese?
What age group consumes the most macaroni and cheese in two days?”
If students are unfamiliar with analyzing databases, model how to read the graph by reading and thinking aloud what each component of the graphs mean. For example, what the various percentages mean for each group of people? What does it mean that some percentages higher than others across the age groups? How much does the students’ age group consume a day?
6. Students will make a claim about the efficiency of their own diet and that of the average American. The claim must be supported by ecological efficiency data from their food web or a food web they create from the database. Guided questions and discussion will be used to support higher analysis of ecological efficiency. Guided questions could include “Which food that you consume is the most/least ecologically efficient in terms of energy transfer?” or “Why might ‘meatless Mondays’ be an important trend in ecological efficiency?”
A rubric could be developed by the teacher, students and peers to rate the depth of the claim, the analytical support of the claim and the clarity of the claim. Students could write their claim in a journal entry, video their claim or produce a public service announcement intended for the food nutrition workers in the school or district.
Assessment
Provide feedback to students as they create their food web to ensure that energy is being transferred in the correct direction. The teacher should also provide feedback on the mathematical computations of energy transfer to ensure correct calculation and conceptual knowledge.
Provide feedback to students on the validity of their dietary efficiency claims. Teachers should watch for incomplete claims that do not indicate a true analysis of data or that lack the demonstration of understanding energy transfer.
Depending on the class size, students may share their claims with the rest of the class, or in groups. Monitor student progress by asking the students to read their claims and back them up with evidence from their diet journals and the “Foods Commonly Eaten in the United States” document.
Peer review should be incorporated either in or out of class as students give each other feedback on the accuracy of their claims.
Adaptations
Students could be asked to analyze only one meal rather than two days of meal tracking.
Students can be given data sets to analyze rather than collecting their own data.
Students can search for data regarding other country’s eating habits.
Different foods from the national data set could be jig-sawed or split rather than each student examining the whole data set.
Selected foods could be chosen from the entire data set.
Students could work in groups to select one group member and analyze only that data.
Supports
A math specialist could be asked to support analysis of mean, SEM and percentages.
Video clips of other organisms in the food web (plants, primary consumers such as cows) could be played to provide context for creating the food web.