The release of A Framework for K–12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (NRC, 2012) provides the basis for the next generation of science standards. This article first describes that foundation for the life sciences; it then presents a draft standard for natural selection and evolution. Finally, there is a discussion of the implications of the new standards for biology programs in general and curriculum, instruction, and assessment in particular.
In the time since the first national standards for science education were released in the mid- to late 1990s, biology advances have included the June 2000 announcement that a majority of the human genome had been sequenced. The completed sequence was announced in April 2003. The latter was almost 50 years to the day (May 1953) after the publication by James Watson and Francis Crick of the structure of DNA. In 2002, Edward O. Wilson published The Future of Life, in which he argued for greater attention to the interactions among human populations and the Earth’s biological systems. Now, it is time for biology educators to consider the next generation of science standards and the implied reform of life science education.
The release of A Framework for K–12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (National Research Council [NRC], 2012) provides a foundation for the next generation of science education standards. As the title indicates, this framework addresses grades K–12, science and engineering practices, crosscutting concepts, and disciplinary core ideas. All of the aforementioned have implications for the biology education community. The three dimensions of the Framework are introduced in the following sections.
Scientific & Engineering Practices
Since the late 1950s, the life sciences curriculum has included both the concepts and the processes of biology. Beginning with the inclusion of inquiry in a framework developed by the Biological Sciences Curriculum Study (BSCS) in the late 1950s, the processes of science (i.e., inquiry) have been a component of BSCS programs and the life science curriculum (Rudolph, 2002, 2008). The 2012 NRC Framework included a new variation on traditional inquiry; namely, science and engineering practices. The science practices are reflective of those described in the AP Standards Science: College Board Standards for College Success (College Board, 2009), and the NRC reports Taking Science to School (Duschl et al., 2007) and Ready Set Science (Michaels et al., 2008). Figures 1, 2, 3, 4, 5, 6, 7 and 8 provide brief summaries of the practices. Those summaries are adapted from the Framework (NRC, 2012) and detailed discussions published in National Science Teachers Association (NSTA) journals (Bybee, 2011a). The scientific and engineering practices are presented in detail because they will continue to be a major component of biology education and, thus, have significant implications for life science programs and classroom practices.
Life Science Core Ideas
The life sciences are based on a small number of unifying principles that explain paradoxical observations – there is both a diversity and a unity of life. On the one hand, there are millions of species of organisms on Earth, and one goal of biologists is to understand the differences among species. On the other hand, living systems share many characteristics and similarities, and understanding this unity is also an aim of life scientists. Although there are many concepts and principles of biology, it is possible to describe a small number of core ideas that form the basis for teaching and learning. The life science core ideas can be used to organize school programs and classroom practices so that students develop an understanding of the patterns and processes of living systems. The NRC Framework proposes the following four disciplinary core ideas for study of the life sciences (see Figure 9).
The first disciplinary core idea – From Molecules to Organisms: Structures and Processes – addresses the structure and function of individual organisms and how these complementary components support life, growth, behavior, and reproduction. The first core idea centers on the unifying principle that cells are the basic unit of life.
The second disciplinary core idea – Ecosystems: Interactions, Energy, and Dynamics – describes organisms’ interactions with other organisms and with their physical environment, how they obtain resources, how changing environmental factors affect organisms, and how organisms change the environment. In addition, the core idea included social interactions and group behavior within and between species and how all of these factors combine to determine ecosystem functioning.
The third disciplinary core idea – Heredity: Inheritance and Variation of Traits across generations – focuses on the transfer of genetic information between generations, explaining the mechanisms of genetic inheritance and describing the environmental and genetic causes of gene mutation and the alteration of gene expression.
The fourth disciplinary core idea – Biological Evolution: Unity and Diversity – presents factors that account for species’ unity and diversity. The idea also involves (a) the evidence, converging from a variety of sources (e.g., comparative anatomy, comparative embryology, molecular biology, and genetics) for shared ancestry; (b) how genetic variation may give some individuals a reproductive advantage in a given environment; (c) how this natural selection leads to adaptation (i.e., it explains the distribution of traits in a population, and how these may change in response to changes in conditions and eventually lead to development of separate species; and (d) how biodiversity is affected by the actions of humans and by other factors.
The disciplinary core ideas describe longstanding foundations for life science education – life processes, heredity, ecology, and evolution. The Framework includes detailed content for the core ideas. That content will be included in the standards and is essential for life science programs. I also note that the core ideas represent an update on the National Science Education Standards (NRC, 1996) and Benchmarks for Science Literacy (AAAS, 1993). In addition, the core ideas align with Science: College Board Standards for College Success (College Board, 2009) and frameworks for the National Assessment for Educational Progress (NAEP) and the international assessments, Trends in International Math and Science Study (TIMSS), and the Program for International Student Assessment (PISA).
In addition to concepts that define the basic structure of biology, the next generation of science standards will include crosscutting scientific concepts. Figure 10 displays those concepts.
Crosscutting concepts are not new to science education. The Benchmarks for Science Literacy (AAAS, 1993) and National Science Education Standards (NRC, 1996) had Common Themes and Unifying Concepts and Processes, respectively. The crosscutting concepts and their respective differences in relation to the nature of science (i.e., patterns and cause-and-effect), sizes and mathematical relationships (i.e., scale, proportion, and quantity), and concepts that unify all areas of science (i.e., systems and system models, energy and matter, structure and function, and stability and change) are detailed in a recent NSTA article (Duschl, 2012).
What is new in the Framework is the requirement that practices, disciplinary core ideas, and crosscutting concepts be articulated as performance expectations in the science education standards.
The Form & Function of the Next Generation of Science Standards
Although the titles and content vary, the categories of science practices, disciplinary core ideas, and crosscutting concepts were in prior standards. In the earlier documents, the categories were described separately and implied that all three dimensions should be addressed in the curriculum. The Framework specifically recommends that standards should emphasize an articulation of all three dimensions: “A major task for developers will be to create standards that integrate the three dimensions. The committee suggests that this integration should occur in the standards statements themselves and in performance expectations that link to the standards” (NRC, 2012, p. 218). To be clear, the form of a standard statement should include a practice, core idea, and crosscutting concept.
Integration of the three dimensions is based on the rationale that (a) in order to understand scientific and engineering ideas, students should engage in the practices of science and engineering; and (b) students cannot learn or show competence in the practices of science and engineering except in the context of specific content.
The integration of practices, core ideas, and crosscutting concepts has been a challenge for the teams developing the next generation of science standards. But the teams have met the challenge. The integration implies a meaningful change in life science instructional materials and assessments. Figure 11 displays a draft of a high school standard for Natural Selection and Evolution.
I specifically sought permission to include the standard on Natural Selection and Evolution for this article. My intention is to send a clear and unequivocal signal that biological evolution will be included in the next generation of science standards. I also add a reference to a recent publication that will support the teaching of evolution in biology classrooms (Bybee & Feldman, 2012).
The standard includes all of the statements of performance expectations (a–e) in the upper portion of Figure 11. The performance expectations that comprise the standard are a combination of a practice, disciplinary core idea, and crosscutting concept, the details of which are referenced in the three foundation columns below the standard. The foundation columns, headed by Science and Engineering Practices, Disciplinary Core Ideas, and Crosscutting Concepts, are from The Framework for K–12 Science Education (NRC, 2012). The specific standard will also include connections to other standards at this grade level, articulation across grade levels, and connections to Common Core State Standards for English Language Arts and Mathematics. Admittedly, this is a lot of detail and information packed into one standard. But it responds to requests from state agencies, school districts, and science teachers.
Standards have the potential to influence all the fundamental components of life science education. This is the function of standards. By fundamental components, I am referring to school programs and teachers’ classroom practices, teacher education and certification, and state standards and assessments.
Examine any of the statements and you will see that they are stated as a performance expectation integrating a practice, core idea, and crosscutting concepts. Using performance expectations places the emphasis on combining practices and content in the assessment of student learning.
Implications for Life Science Teachers & Teaching
The next generation of science standards builds on an earlier generation of standards (NRC, 1996) and presents new challenges for the biology education community in general and for life science teachers in particular.
For the biology education community, there is the fact that any framework or set of standards has limits. All the subdisciplines of biology cannot be represented, and all the facts and content within one area cannot be included. The standards center on the major conceptual areas of the discipline and the core ideas in that area.
The new standards provide a contemporary view of science practices and make a direct connection between specific practices and biological concepts. Although the standards directly address students’ performance expectation and thus assessment, the implication for curriculum and instruction is not far to seek. Science practices have a richer meaning than the past methods, processes, or inquiry (see, e.g., Bybee, 2011b; Krajcik & Merritt, 2012).
The science standards will include technology and engineering. As a point of historical reference, I note the inclusion of concepts and processes of technology and engineering in Science for All Americans (Rutherford & Ahlgren, 1989) and both Benchmarks for Science Literacy (AAAS, 1993) and National Science Education Standards (NRC, 1996). For a more detailed clarification, I refer readers to a recent article by Cary Sneider (2012).
In the 21st century, the continued separation of science and technology and, especially, a bias against technology are simply inappropriate given the complementary relationship between the two disciplines. One of the great advances of the 20th century, sequencing of the human genome, could not have been completed in such a short period without technology. As a beginning, life science teachers can review the scientific and engineering practices described in this article and begin introducing students to the similarities and differences in historical examples, contemporary advances, and their work in the life science classroom.
Life science teachers have a variety of things to consider as they strive to address 21st-century perspectives (Bybee, 2011b). Advances in our understanding of how students learn (Bransford et al., 2000; Donovan et al., 2000), 21st-century skills (NRC, 2008), and societal challenges in food, energy, environment, and health (NRC, 2009) are among the contextual themes for curriculum, instruction, and assessment in biology. Although important, considerations such as these require an understanding of scientific and engineering practices and disciplinary core ideas in the life sciences. The next generation of science standards provides that foundation.
The justifications for improving life science education are not difficult to find, but one of the most significant will be the states’ adoption of the science standards and the implications of those standards for assessments.
I will end with an observation based on prior work on national standards. The next generation of science standards is the first, easiest, and least expensive step in the reform of biology education. Development of new life science programs, changing assessments, and professional development of biology teachers present the more essential challenges. The latter also will result in the greatest benefit to our students and society.