The next generation of science standards: implications for biology education.
Abstract: 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.
Article Type: Report
Subject: Natural selection
Author: Bybee, Rodger W.
Pub Date: 10/01/2012
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
Accession Number: 303450257
Full Text: 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.

DOI: 10.1525/abt.2012.74.8.3


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:
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

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

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

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

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

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

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

* 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,

* 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


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,

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]


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.


MP.3 Construct viable arguments and critique the reasoning of

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.
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