Addressing Sustainability in the High School Biology Classroom through Socioscientific Issues

By inergency On Mar 26, 2023

Addressing Sustainability in the High School Biology Classroom through Socioscientific Issues

4.1. Program Redesign

The initial version of SGI received very positive feedback and was used widely in classrooms across the United States. The redesign needed to build upon this prior work while embracing the new developments in the field of sustainability and addressing the new standards. The general steps involved in the redesign process are shown in Figure 3. The SEPUP curriculum developers reaffirmed the use of sustainability as the overarching course theme, based on the demonstrated value of using the three pillars of sustainability framework for enabling students to see the relevance of science to their lives and those of their family, friends, and community members.

The next step was to define the scope and configuration of the biology content that would be incorporated into the curriculum. Since the goal was to align with the NGSS, the course would include all 24 Performance Expectations (what students should know and be able to do at the end of instruction) in Life Science and an additional two Performance Expectations (PEs) in Engineering, Technology, and Applications of Science explicitly linked in the standards to Life Science. The curriculum developers organized the PEs into bundles to determine the course units. The units of Ecology, Cells, Genetics, and Evolution are organized around core ideas which “have a long history and solid foundation based on the research evidence established by many scientists working across multiple fields” [1] (p. 141). Most significantly, the development team decided to reconfigure the first unit as a short introductory sequence on sustainability to provide an overarching thematic framework for the entire program. This introductory sequence provided students with an engaging, low-stakes opportunity to become familiar with the SGI approach to sustainability and set them up for success in the four larger units.

Figure 3 presents the process used by SEPUP curriculum developers in redesigning Science and Global Issues to align with the Next Generation Science Standards. The process is linear in the first few steps but becomes iterative in the later steps.

The fourth step of sequencing the content within units is essential for determining an issue that will connect well through the unit. Many of the PEs had been written in such a way as to suggest a possible logical sequence for student learning. For example, the first PE in ecology required students to understand that all populations of organisms have the potential to grow exponentially. This understanding was essential for most of the remaining PEs in the ecology bundle. Thus, it made sense to address this PE first in the Ecology unit. In some cases, the ordering of the PEs was less obvious, and in a small number of cases, modifications were made to the order after the unit issue had been chosen; this is indicated by the narrow arrow pointing backwards to this step in Figure 3.

The fifth step in the process involved identifying the socioscientific issue to drive the learning for an entire unit of 15 to 17 activities. General criteria for selecting an issue included: (1) the issue requires students to develop an understanding of multiple PEs that are applied over the course of the entire unit; (2) the issue is current and has an audience or stakeholder community that cares about the findings and possible solutions; (3) the issue has the potential to build upon local, everyday, or family experiences throughout the unit, helping students to see the relevance of the issue to their everyday lives; (4) the issue should be compelling to students from a wide range of communities, including students from varying educational, economic, and cultural backgrounds; and (5) the issue can be made observable to students through one or more of the following: (a) a case(s), scenario, data set, video, photographs, or a simple data visualization (e.g., a graph). To ensure the chosen issue worked with the sustainability theme, the developers also considered if the issue connected well across the NGSS science content addressed in the unit, that it could be significantly informed by scientific evidence relevant to the unit, and that the issue did not have an easy solution. The medium-width arrow in the flowchart indicates that occasionally, unit issues continued to be refined as development progressed. The issues and corresponding overarching questions for the introductory sequence and content units are shown in Table 1.

Table 1 presents the titles of the five units in Science and Global Issues, the unit issues, and the overarching questions that drive the storyline and learning sequences throughout the unit.

The sixth step entailed identifying investigative phenomena. Penuel and Bell argued that “Instructional sequences are more coherent when students investigate compelling natural phenomena (in science) or work on meaningful design problems (in engineering) by engaging in the science and engineering practices” [24]. This aligns well with SEPUP’s instructional model. As such, the developers divided each unit into learning sequences that averaged approximately five activities, each driven by an investigative phenomenon. In SGI, the requirements for an investigative phenomenon are as follows: ( 1) it can be made observable to students through a case, scenario, data set, video, photographs, a simple data visualization (e.g., graph) or other appropriate means; (2) it involves something that is puzzling or instigates student questioning or wonderment; (3) it drives a sequence of learning and may cover one or more PEs because it is too complex to be explained in one activity; (4) it is connected and/or relevant to the sustainability challenge presented by the unit issue in a way that is obvious to students and allows them to engage in sensemaking as they build conceptual understanding or gather evidence that they will use to develop their solution or recommendation in response to the unit issue.

The final step in the redesign process was to develop a storyline that provides a coherent flow to the unit, moving from one learning sequence to the next. The SEPUP storyline is built around the science and engineering concepts needed to explain phenomena and solve problems related to the sustainability issue under investigation. By answering the driving question for each investigative phenomenon, students move through the storyline and deepen their understanding of how various science and engineering concepts and ideas are woven together across the entire unit and how they connect to the sustainability issue. As students work to answer the driving question posed in each learning sequence, they engage in active learning and sensemaking that integrate the three dimensions of the NGSS (disciplinary core ideas, science and engineering practices, and crosscutting concepts), gathering evidence from a variety of sources and investigations as they build an increasingly sophisticated explanation for how or why something happens in the natural world. Ultimately, students apply what they have learned to make a decision about or propose a solution to the sustainability challenge presented by the unit issue. As shown in Figure 3, this step is highly iterative and is modified as needed until the redesign is completed.

An additional component of the process not captured in Figure 3 was the goal of showing how some sustainability issues cross unit and content boundaries. To accomplish this goal, developers sometimes used specific contexts for addressing issues that would be revisited in subsequent units. This approach allows students to develop an appreciation for the complexity of problems in sustainability and the need to incorporate scientific knowledge from multiple disciplines when attempting to develop solutions. Table 2 shows the specific contexts for addressing issues through SGI. For example, the sustainability of fisheries is used as the primary context throughout the Ecology unit. Students explore what may cause a fishery’s population to decline in numbers due to both natural and human-caused changes in the environment. They consider different approaches to promoting the sustainability of fisheries based on ecological, social, and economic perspectives. This fishery context is revisited again at the end of the Evolution unit, this time in the context of unintended evolutionary changes: human impact on the environment is causing fish species to evolve to a smaller body size, which also impacts the sustainability of the fishery. In another example, the Cells unit explores how climate change affects human health, specifically how global warming increases the prevalence of infectious diseases. The Evolution unit revisits this issue from the perspective of how global warming is affecting the evolution of the pathogens that cause these diseases.

Table 2 also shows how these contexts align with UN Sustainable Development Goals. Some of the contexts are more substantially aligned than others. For example, the Cells unit focuses on how climate change is affecting human health, with numerous opportunities for students to examine these connections. Thus, the unit is well aligned with SDG Goal 3: Good Health and Well-being. The unit identifies the cause of some infectious diseases as water-borne pathogens, which become a problem when people do not have access to clean drinking water. The unit does not delve into this specific sustainability issue in depth, so it is less deeply aligned with SDG Goal 6: Clean Water and Sanitation.

Table 2 presents the UN SDGs addressed in Science and Global Issues, and the contexts for addressing them in the four NGSS content units; specific contexts were sometimes used in more than one unit.

4.2. Unit Specific Example (Genetics)

Thus far, we have described the general process of developing a curriculum around sustainability-oriented socioscientific issues in order to provide a big picture view of how this approach might be embodied. However, in order to conceptualize in more detail how this might look in a classroom day-to-day, it is important to have a clear picture of a curricular unit from beginning to end. It is fairly easy to make meaningful connections between sustainability and some common topics covered in a traditional high school biology course, such as species loss due to habitat destruction. Other areas are less straightforward. What connections are there between mitosis and sustainability? How can one relate an understanding of sustainability to that of enzyme structure and function? Issue-oriented science allows students to approach these less straightforward areas and make more nuanced, subtle connections between sustainability and biology. It allows students to see firsthand the interconnectedness of sustainability and all aspects of biological science through examples from real-world contexts and stories that they can engage with. To make these seemingly abstract topics relevant and compelling, the Genetics unit examines the issue that although people rely on genetically engineered crops to maintain a global food supply, the use of this technology can impact sustainability. Specifically, students investigate how genetically engineered crops affect the sustainability of food production.

Students begin the unit with a basic introduction to genetic modification and examine data that show a significant increase in herbicide-resistant weed species in the United States since the introduction of genetically modified, herbicide-resistant soy plants in the mid-1990s. Students are then presented with a fictitious scenario that mirrors real-world situations in which a farmer has discovered “superweeds” in their fields. These superweeds are a common weed species that have acquired a genetically modified trait, such as herbicide resistance, that makes them more difficult to control. Students follow this scenario through three learning sequences which introduce genetics content alongside the problem faced by the farmer. As students deepen their understanding of the core content, they are simultaneously gathering evidence that will help them to evaluate potential solutions to the issue. Within individual activities, the developers consistently and explicitly provide opportunities for students to think through the connections between the core scientific concepts and the unit-specific issue related to sustainability. These connections are embedded throughout the activity procedures and questions that help them build understanding. The unit issue, which in this instance is genetic modification and sustainable food production, is always at the forefront of student learning. This intentionality provides a storyline for students to follow, and allows students to immediately see the applicability of the core genetics content in the “real” world. Coupling the issue with sustainability further serves to underscore the importance of understanding and applying the scientific content to global sustainability challenges, ideally leading to increased student engagement and scientific literacy. The context and examples for these development guidelines are detailed for the Genetics unit below.

The first learning sequence of six activities focuses on the investigative phenomenon of how superweeds were initially introduced to the farmer’s field. Students learn what superweeds are and how genetically modified organisms are created, and they begin to understand the impact these plants can have on crop production. As students learn about mitosis and asexual reproduction, they make sense of how an organism with a genetic modification would carry that modification in all (or nearly all) cells of its body. Learning about basic genetic crosses for specific traits helps students figure out how a genetic modification might pass from one generation to the next. At the end of the learning sequence, students should have a better understanding of the potential challenge of superweeds in terms of the sustainability of the global food supply and at least an initial understanding of some of the ways that superweeds might have appeared in this farmer’s fields.

The second learning sequence of the unit centers on the investigative phenomenon of superweeds appearing in different locations that are far apart from each another. Over the course of seven activities, students learn about protein synthesis, cell differentiation, gene expression, the molecular mechanism of enzymes, d how mutations can affect enzyme function (particularly how this can be harnessed to create herbicide resistance), meiosis, and sexual reproduction. They also learn how individual genes or gene sequences can be identified in an organism. Many herbicides target specific enzymes or sets of enzymes that plants require to grow. The genetic modification of crop plants for herbicide resistance often relies on using a mutation in a gene for an enzyme that prevents it from binding with an herbicide while remaining functional. Students can contextualize their understanding of protein synthesis (production of enzymes), enzyme function, genetic mutation, gene expression, meiosis, and sexual reproduction within the superweed scenario. At the conclusion of each activity, students work through questions that are designed to help them make connections between the core science content and how it relates to both the specific superweed scenario and the overall sustainability of global crop production. For example, at the conclusion of the activity on meiosis, students discuss the following:

Farmer Green is still not sure if the superweeds in his fields are herbicide resistant because of a mutation or if they are the result of transgene migration from herbicide resistant corn, like the corn he grows, to a weedy relative. What question does Farmer Green need answered to determine which scenario occurred? Use what you know about DNA and genes leading to the formation of proteins to explain how the answer to your question would help Farmer Green figure out which scenario occurred. Hint: Think about what genes the superweeds would have in each scenario and if the genes would produce the modified EPSPS enzyme or a different type of protein.

This discussion leads to subsequent activities in which students learn more in-depth information about genetics (e.g., diploid versus haploid cells) and then about how gel electrophoresis can be used to compare genetic sequences and identify specific genes in DNA samples, all in the context of Farmer Green comparing the DNA from his superweeds to that from neighboring farms. This exploration helps students answer the question of whether the superweeds are the result of a spontaneous mutation or transgene migration.

The third and final learning sequence of the four activities brings together everything the students have been learning to examine the benefits and trade-offs of potential solutions for maintaining sustainable global and/or local food production. They focus on answering the driving question: Are genetically modified organisms the solution for sustainable global food production? The content in this learning sequence also brings together other areas students have studied in previous units (ecology and cell biology) and foreshadows topics in the final unit, which that follows genetics (evolution, especially natural selection). Students begin the learning sequence with an investigation into how superweeds can affect local biodiversity by analyzing and interpreting data on patterns of weed and insect populations prior to and after reports of superweeds being present in fields. The students’ analysis of the data and what it means for local biodiversity requires them to incorporate what they learned about biodiversity in the ecology unit and begin to weigh what they have learned about genetic modification and the potential trade-offs involved in its use. Students then apply this understanding in the following activity, which involves reading about the benefits and trade-offs of genetic modification in several case studies, all involving food production (golden rice, disease-resistant rice, salmon modified for faster growth, and virus-resistant papaya). This provides students with a broader conception of the potential benefits and trade-offs of genetic modification as it relates to the sustainability of global food production.

The third activity of the sequence has students again apply their understanding of genetics, genetic modification, and relevant the benefits and trade-offs in an expansion of the Farmer Green scenario in which students are asked to analyze data about the sustainability of the agriculture of the entire area. Based on the patterns presented in the data, students make an evidence-informed recommendation as to whether the area should grow genetically modified soy. This activity supports students in applying their understanding of genetics and genetic modification to analyzing a specific scenario and potential solution in the context of sustainable food production. As students reflect on their analysis, the activity concludes with students answering the question What information should policymakers evaluate when making decisions about genetically modified organisms? Thus, they return to connecting what they are currently learning to real-world contexts. The students conclude the unit with an evaluation of four alternative farming proposals that address superweeds. Students focus on how the outcome of each proposal may affect the sustainability of agriculture in the area. Supported by evidence, the students construct a recommendation for the proposal of their choice, present it to the class, and independently write up their recommendation. As part of their recommendation, they answer the questions shown in Table 3. An example of one student’s written answers to questions 1 and 2, collected during the field testing of the course, are shown as well.

Table 3 presents questions used with students in the Science and Global Issues Genetics unit and actual responses provided by a student during the field test of the program.

This student’s responses clearly show that they were able to bring together their understanding of the core scientific content, the unit issue, and the concept of sustainability. Teachers can then use the concluding class discussion to delve more deeply into the students’ explanation of how problems with monoculture relate to genetics and genetic diversity or why there would be a reduction in transgene migration, both of which are referred to in their written response. The field test teachers commented on the students’ written and oral responses in their feedback, noting that students were consistently engaged and made connections between the traditional science content, sustainability, and the specific unit issue. One teacher summarized this by saying: “I think the activities nicely and clearly lead to the students developing understanding and skills that allow them to make evidence-based decisions at the end.” Furthermore, the continuous storyline, which focused on the socioscientific issue of superweeds and their effects on the sustainability production, provided further motivation for students to make these connections. This was captured in another teacher’s comment: “The investigative phenomenon provides a strong reason for students to understand why an understanding of genetics is important and a different perspective other than just what traits you inherit from your parents.”