The next generation of science standards: implications for biology education.
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.
Key Words: Life science standards; science and engineering practices; crosscutting concepts; disciplinary core ideas; curriculum; instruction; and assessment.
|Author:||Bybee, Rodger W.|
|Publication:||Name: The American Biology Teacher Publisher: National Association of Biology Teachers Audience: Academic; Professional Format: Magazine/Journal Subject: Biological sciences; Education Copyright: COPYRIGHT 2012 National Association of Biology Teachers ISSN: 0002-7685|
|Issue:||Date: Oct, 2012 Source Volume: 74 Source Issue: 8|
|Topic:||Event Code: 350 Product standards, safety, & recalls|
|Product:||Product Code: 8200000 Education NAICS Code: 61 Educational Services|
|Organization:||Organization: National Research Council; National Science Teachers Association|
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 1-8 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).
* Crosscutting Concepts
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.
* Concluding Discussion
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.
AAAS. (1993). Benchmarks for Science Literacy. New York, NY: Oxford University Press.
Bransford, J., Brown, A. & Cocking, R., Eds. (2000). How People Learn: Brain, Mind, Experience, and School: Expanded Edition. Washington, D.C.: National Academies Press.
Bybee, R.W. (2011a). Scientific and engineering practices in K-12 classrooms. Science Teacher, 78, 34-40.
Bybee, R.W. (2011b). The Teaching of Science: 21st Century Perspectives. Arlington, VA: NSTA Press.
Bybee, R.W. & Feldman, J. (2012). EVO Teachers Guide: Ten Questions Everyone Should Ask about Evolution. Arlington, VA: NSTA Press.
College Board. (2009). Science: College Board Standards for College Success. New York, NY: College Board.
Donovan, M.S., Bransford, J.D. & Pellegrino, J.W., Eds. (2000). How People Learn: Bridging Research and Practice. Washington, D.C.: National Academies Press.
Duschl, R.A. (2012). The second dimension--crosscutting concepts: understanding A Framework for K-12 Science Education. Science Teacher, 79, 34-38.
Duschl, R.A., Schweingruber, H.A. & Shouse, A.W., Eds. (2007). Taking Science to School: Learning and Teaching Science in Grades K-8. Washington, D.C.: National Academies Press.
Krajcik, J. & Merritt, J. (2012). Engaging students in scientific practices: what does constructing and revising models look like in the science classroom? Understanding A Framework for K-12 Science Education. Science Teacher, 79, 38-41.
Michaels, S., Shouse, A.W. & Schweingruber, H.A., Eds. (2008). Ready, Set, Science! Putting Research to Work in K-8 Science Classrooms. Washington, D.C.: National Academies Press.
National Research Council. (1996). National Science Education Standards. Washington, D.C.: National Academies Press.
National Research Council. (2008). Research on Future Skill Demands: A Workshop Summary. Washington, D.C.: National Academies Press.
National Research Council. (2009). The New Biology for the 21st Century. Washington, D.C.: National Academies Press.
National Research Council. (2012). A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas. Washington, D.C.: National Academies Press.
Rudolph, J.L. (2002). Scientists in the Classroom: The Cold War Reconstruction of American Science Education. New York, NY: Palgrave Macmillan.
Rudolph. J.L. (2008). The legacy of inquiry and the Biological Sciences Curriculum Study. In R. Bybee (Ed.), BSCS: Measuring Our Success. Colorado Springs, CO: Biological Sciences Curriculum Study (BSCS).
Rutherford, F.J. & Ahlgren, A. (1989). Science for All Americans. New York, NY: Oxford University Press.
Sneider, C. (2012). Core ideas of engineering and technology: understanding A Framework for K-12 Science Education. Science Teacher, 79, 32-36.
Wilson, E.O. (2002). The Future of Life. New York, NY: Knopf.
RODGER W. BYBEE is Retired Executive Director of the Biological Sciences Curriculum Study, 670 Ridgeside Dr., Golden, CO 80401. He was also Executive Director of the Center for Science, Mathematics, and Engineering Education at the National Research Council, where he led the development of the National Science Education Standards. E-mail: email@example.com.
Figure 1. Asking questions and defining problems. Science begins with a question about a natural phenomenon. A basic practice of the scientist is the ability to formulate empirically answerable questions about phenomena to establish what is already known, and to determine what questions have yet to be satisfactorily answered. Engineering begins with a problem that needs to be solved. A basic practice of engineers is to ask questions to clarify the problem, determine criteria for a successful solution, and identify constraints. Figure 2. Developing and using models. Science often involves the use of models to help develop explanations about natural phenomena. Models enable predictions of the form "if ... then ... therefore" to be made in order to test hypothetical explanations. Engineering makes use of models to analyze systems to identify flaws that might occur, or to test possible solutions to a new problem. Engineers design and use models to test proposed systems and to recognize the strengths and limitations of their designs. Figure 3. Planning and carrying out investigations. Scientific investigations are a major practice of scientists in planning and carrying out systematic investigations that require clarifying what counts as data and in experiments identifying variables. Engineering investigations are conducted to gain data essential for specifying criteria and to test proposed designs. Engineers must identify relevant variables, decide how they will be measured, and collect data for analysis. Their investigations help them to identify the effectiveness, efficiency, and durability of designs under different conditions. Figure 4. Analyzing and interpreting data. Scientific investigations produce data that must be analyzed in order to derive meaning. Because data usually do not speak for themselves, scientists use a range of tools--including tabulation, graphical interpretation, visualization, and statistical analysis-to identify the significant features and patterns in the data. Sources of error are identified and the degree of certainty calculated. Modern technology makes the collection of large data sets much easier, providing secondary sources for analysis. Engineering investigations include analysis of data collected in the tests of designs. This allows comparison of different solutions and determines how well each meets specific design criteria--that is, which design best solves the problem within given constraints. Engineers require a range of tools to identify the major patterns and interpret the results. Advances in science make analysis of proposed solutions more efficient and effective.
Figure 5. Using mathematics and computational thinking. In science, mathematics and computation are fundamental tools for representing physical variables and their relationships. They are used for a range of tasks, such as constructing simulations; statistically analyzing data; and recognizing, expressing, and applying quantitative relationships. Mathematical and computational approaches enable prediction of the behavior of systems along with the testing of such predictions. Moreover, statistical techniques are also invaluable for identifying significant patterns and establishing correlational relationships. In engineering, mathematical and computational representations of established relationships and principles are an integral part of the design process. For example, structural engineers create mathematics-based analysis of designs to calculate whether they can stand up to expected stresses of use and be completed within acceptable budgets. Moreover, simulations provide an effective test bed for the development of designs as proposed solutions to problems and for their improvement, if required.
Figure 6. Constructing explanations and designing solutions. The goal of science is the construction of theories that provide explanatory accounts of the material world. A theory becomes accepted when it has multiple independent lines of empirical evidence, greater explanatory power, a breadth of phenomena it accounts for, and explanatory coherence and parsimony. The goal of engineering design is a systematic solution to problems. Each proposed solution results from a process of balancing competing criteria of desired functions, technical feasibility, cost, safety, aesthetics, and compliance with legal requirements. The optimal choice depends on how well the proposed solution meets criteria and constraints.
Figure 7. Engaging in argument from evidence. In science, reasoning and argument are essential for clarifying strengths and weaknesses of a line of evidence and for identifying the best explanation for a natural phenomenon. Scientists must defend their explanations, formulate evidence based on a solid foundation of data, examine their understanding in light of the evidence and comments by others, and collaborate with peers in searching for the best explanation for the phenomena being investigated. In engineering, reasoning and argument are essential for finding the best solution to a problem. Engineers collaborate with their peers throughout the design process. A critical stage is the selection of the most promising solution among a field of competing ideas. Engineers use systematic methods to compare alternatives, formulate evidence based on test data, make arguments to defend their conclusions, critically evaluate the ideas of others, and revise their designs in order to identify the best solution. Figure 8. Obtaining, evaluating, and communicating information. Science cannot advance if scientists are unable to communicate their findings clearly and persuasively or learn about the findings of others. A major practice of science is thus to communicate ideas and the results of inquiry-orally; in writing; with the use of tables, diagrams, graphs, and equations; and by engaging in extended discussions with peers. Science requires the ability to derive meaning from scientific texts such as papers, the Internet, symposia, or lectures to evaluate the scientific validity of the information thus acquired and to integrate that information into proposed explanations. Engineering cannot produce new or improved technologies if the advantages of their designs are not communicated clearly and persuasively. Engineers need to be able to express their ideas orally and in writing; with the use of tables, graphs, drawings, or models; and by engaging in extended discussions with peers. Moreover, as with scientists, they need to be able to derive meaning from colleagues' texts, evaluate information, and apply it usefully. Figure 9. Disciplinary core ideas: life sciences. 1. From Molecules to Organisms: Structures and Processes A: Structure and Function B: Growth and Development of Organisms C: Organization for Matter and Energy Flow in Organisms D: Information Processing 2. Ecosystems: Interactions, Energy, and Dynamics A: Interdependent Relationships in Ecosystems B: Cycles of Matter and Energy Transfer in Ecosystems C: Ecosystem Dynamics, Functioning, and Resilience D: Social Interactions and Group Behavior 3. Heredity: Inheritance and Variation of Traits A: Inheritance of Traits B: Variation of Traits 4. Biological Evolution: Unity and Diversity A: Evidence of Common Ancestry and Diversity B: Natural Selection C: Adaptation D: Biodiversity and Humans
Figure 10. Crosscutting science concepts (NRC, 2012). * Patterns * Cause and Effect: Mechanism and Explanation * Scale, Proportion, and Quantity * Systems and System Models * Energy and Matter: Flows, Cycles, and Conservation * Structure and Function * Stability and Change Figure 11. HS.LS-NSE Natural Selection and Evolution. This standard is from an early draft of the next generation of science standards and will be revised on the basis of feedback from states and public reviews. The standard is presented here with permission from Achieve and is intended as an example of the basic architecture and presentation for the standards. HS.LS-NSE Natural Selection and Evolution Students who demonstrate understanding can: a. Use a model to explain that the process of natural selection is the result of four factors: (1) the potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment. [Clarification Statement: Mathematical models may be used to communicate the explanation, 2) refers the heritable genetic variation, and phenotypic variation it leads to among individual in a specie due to mutation and sexual reproduction] b. Use evidence to explain how natural selection, genetic drift, gene flow through migration and co-evolution leads to adaptations that result in populations dominated by organisms that are anatomically, behaviorally, and physiologically able to survive and reproduce in a specific environment. [Assessment Boundary: Evidence should center on survival advantages of selected traits for different environmental changes such as temperature, climate, acidity, light, biotic factors] c. Analyze and interpret data to support explanations for the processes by which organisms with an advantageous heritable trait tend to increase in numbers in future generations, and organisms that lack an advantageous heritable trait tend to decrease in numbers in future generations. [Clarification: Data on a specific environment and changes in the environment over time is analyzed using computational thinking] d. Obtain, evaluate and communicate information describing how changes in environmental conditions can affect the distribution of traits in a population causing 1) increases in the population of some species, 2) the emergence over time of new species, and 3) the extinction of other species. Use evidence obtained from technology to compare similarities in DNA sequences, anatomical structures, and order of appearance of structures in embryological development to support common lines of descent in evolution. [Clarification: add boundary] e. Plan and carry out investigations to gather evidence of patterns in the relationship between natural selection and changes in the environment. [Clarification Statement: A possible investigation could be to study fruit flies and the number or eggs, larvae, and flies that hatch in response to environmental changes such as temperature, moisture, and acidity over multiple generations] The performance expectations above were developed using the following elements from the NRC document A Framework for K-12 Science Education: Science and Engineering Practices Developing and Using Models Modeling in 9-12 builds on K-8 and progresses to using, synthesizing, and constructing models to predict and explain relationships between systems and their components in the natural and designed world. * Use multiple types of models to represent and explain phenomena and move flexibly between model types based on merits and limitations, (a) Planning and Carrying Out Investigations Planning and carrying out investigations to answer questions or test solutions to problems in 9-12 builds on K-8 experiences and progresses to include investigations that build, test, and revise conceptual, mathematical, physical, and empirical models. * Evaluate various methods of collecting data (e.g., field study, experimental design, simulations) and analyze components of the design in terms of various aspects of the study. Decide types, how much, and accuracy of data needed to produce reliable measurement and consider any limitations on the precision of the data (e.g., number of trials, cost, risk, time), (f) Analyzing and Interpreting Data Analyzing data in 9-12 builds on K-8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data. * Use tools, technologies, and/or models (e.g., computational, mathematical) to generate and analyze data in order to make valid and reliable scientific claims or determine an optimal design solution, (c) * Consider limitations (e.g., measurement error, sample selection) when analyzing and interpreting data, (c) * Compare and contrast various types of data sets (e.g., self-generated, archival) to examine consistency of measurements and observations, (c) Constructing Explanations and Designing Solutions Constructing explanations and designing solutions in 9-12 builds on K-8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific knowledge, principles, and theories. * Apply scientific reasoning, theory, and models to link evidence to claims and show why the data are adequate for the explanation or conclusion, (b) * Construct and revise explanations and arguments based on evidence obtained from a variety of sources (e.g., scientific principles, models, theories) and peer review, (b) * Base casual explanations on valid and reliable empirical evidence from multiple sources and the assumption that natural laws operate today as they did in the past and will continue to do so in the future, (b) Obtaining, Evaluating, and Communicating Information Obtaining, evaluating, and communicating information in 9-12 builds on 5-8 and progresses to evaluating the validity and reliability of the claims, methods, and designs. * Critically read scientific literature adapted for classroom use to identify key ideas and major points and to evaluate the validity and reliability of the claims, methods, and designs, (d), (e) * Generate, synthesize, communicate, and critique claims, methods, and designs that appear in scientific and technical texts or media reports, (d), Disciplinary Core Ideas LS4.A: Evidence of Common Ancestry and Diversity * Genetic information, like the fossil record, also provides evidence of evolution. DNA sequences vary among species, but there are many overlaps; in fact, the ongoing branching that produces multiple lines of descent can be inferred by comparing the DNA sequences of different organisms. Such information is also derivable from the similarities and differences in amino acid sequences and from anatomical and embryological evidence, (e) LS4.B: Natural Selection * Natural selection occurs only if there is both (1) variation in the genetic information between organisms in a population and (2) variation in the expression of that genetic information-that is, trait variation-that leads to differences in performance among individuals. (a),(c) * The traits that positively affect survival are more likely to be reproduced, and thus are more common in the population, (b), (c), (d), (f) LS4.C: Adaptation * Natural selection is the result of four factors: (1) the potential for a species to increase in number, (2) the genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for an environment's limited supply of the resources that individuals need in order to survive and reproduce, and (4) the ensuing proliferation of those organisms that are better able to survive and reproduce in that environment, (a) * Natural selection leads to adaptation, that is, to a population dominated by organisms that are anatomically, behaviorally, and physiologically well suited to survive and reproduce in a specific environment. That is, the differential survival and reproduction of organisms in a population that have an advantageous heritable trait leads to an increase in the proportion of individuals in future generations that have the trait and to a decrease in the proportion of individuals that do not. (b), (c), (f) * Adaptation also means that the distribution of traits in a population can change when conditions change, (d) * Changes in the physical environment, whether naturally occurring or human induced, have thus contributed to the expansion of some species, the emergence of new distinct species as populations diverge under different conditions, and the decline-and sometimes the extinction-of some species, (d) * Species become extinct because they can no longer survive and reproduce in their altered environment. If members cannot adjust to change that is too fast or drastic, the opportunity for the species' evolution is lost, (d) Crosscutting concepts Patterns Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena. Classifications or explanations used at one scale may fail or need revision when information from smaller or larger scales is introduced; thus requiring improved investigations and experiments. Patterns of performance of designed systems can be analyzed and interpreted to reengineer and improve the system, (c), (e), (f) Cause and Effect Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects. Cause and effect relationships can be suggested and predicted for complex natural and human designed systems by examining what is known about smaller scale mechanisms within the system. Systems can be designed to cause a desired effect. Changes in systems may have various causes that may not have equal effects, (a), (b), (d) Connections to other topics in this grade-level: HS.ESS-HE, HS.ESS-CC Articulation across grade-levels: MS.LS-NSA, MS.LS-GDRO Common Core State Standards Connections: [Note: these connections will be made more explicit and complete In future draft releases] ELA-- RI.9-10.8 Delineate and evaluate the argument and specific claims in a text, assessing whether the reasoning is valid and the evidence is relevant and sufficient; identify false statements and fallacious reasoning. RI.9-10.1 Cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text. RI.9-10-8 Delineate and evaluate the argument and specific claims in a text, assessing whether the reasoning is valid and the evidence is relevant and sufficient identify false statements and fallacious reasoning. SL.9-10.2 Integrate multiple sources of information presented in diverse media or formats (e.g., visually, quantitatively, orally) evaluating the credibility and accuracy of each source. SL.11-12.2 Integrate multiple sources of information presented in diverse formats and media (e.g., visually, quantitatively, orally) in order to make informed decisions and solve problems, evaluating the credibility and accuracy of each source and noting any discrepancies among the data. Mathematics-- MP.3 Construct viable arguments and critique the reasoning of others. N-Q Reason quantitatively and use units to solve problems. S.ID Summarize, represent, and interpret data on a single count or measurement variable. S.IC Make inferences and justify conclusions from sample surveys, experiments, and observational studies.
|Gale Copyright:||Copyright 2012 Gale, Cengage Learning. All rights reserved.|