Middle School Life Sciences
Students in middle school develop understanding of key concepts to help them make sense of the life sciences.
These ideas build upon students’ science understanding from earlier grades and from the disciplinary core
ideas, science and engineering practices, and crosscutting concepts of other experiences with physical and
Earth sciences. There are five life science topics in middle school: (1) Structure, Function, and
Information Processing; (2) Growth, Development, and Reproduction of Organisms; (3) Matter and Energy
in Organisms and Ecosystems; (4) Interdependent Relationships in Ecosystems; and (5) Natural Selection
and Adaptations. The performance expectations in middle school blend core ideas with science and engineering
practices and crosscutting concepts to support students in developing useable knowledge across the science
disciplines. While the performance expectations in middle school life sciences couple particular practices
with specific disciplinary core ideas, instructional decisions should include the use of many science and
engineering practices integrated in the performance expectations. The concepts and practices in the performance
expectations are based on the grade-band endpoints described in the NRC Framework.
Structure, Function, and Information Processing
The Performance Expectations in Structure, Function, and Information Processing help students formulate an answer to the
question, “How do the structures of organisms contribute to life’s functions?” Middle school students can plan and carry
out investigations to develop evidence that living organisms are made of cells and to determine the relationship of
organisms to the environment. Students can use understanding of cell theory to develop physical and conceptual models
of cells. They can construct explanations for the interactions of systems in cells and organisms and for how organisms
gather and use information from the environment. By the end of their studies, students understand that all organisms are
made of cells, that special structures are responsible for particular functions in organisms, and that for many organisms
the body is a system of multiple interacting subsystems that form a hierarchy from cells to the body. Crosscutting concepts
of cause and effect, structure and function, and matter and energy are called out as organizing concepts for these core ideas.
Growth, Development, and Reproduction of Organisms
The Performance Expectations in Growth, Development, and Reproduction of Organisms help students formulate an answer to the
question, “How do organisms grow, develop, and reproduce?” Students understand how the environment and genetic factors determine
the growth of an individual organism. They also demonstrate understanding of the genetic implications for sexual and asexual
reproduction. Students can develop evidence to support their understanding of the structures and behaviors that increase the
likelihood of successful reproduction by organisms. They have a beginning understanding of the ways in which humans can select
for specific traits, the role of technology, genetic modification, and the nature of ethical responsibilities related to
selective breeding. At the end of middle school, students can explain how select structures, functions, and behaviors of
organisms change in predictable ways as they progress from birth to old age. Students can use the practices of analyzing
and interpreting data, using models, conducting investigations, and communicating information. Crosscutting concepts of
structure and function, change and stability, and matter and energy flow in organisms support understanding across this topic.
Matter and Energy in Organisms and Ecosystems
The Performance Expectations in Matter and Energy in Organisms and Ecosystems help students formulate answers to the
questions: “How do organisms obtain and use matter and energy? How do matter and energy move through an ecosystem?” Middle
school students can use conceptual and physical models to explain the transfer of energy and cycling of matter as they
construct explanations for the role of photosynthesis in cycling matter in ecosystems. They can construct explanations
for the cycling of matter in organisms and the interactions of organisms to obtain matter and energy from an ecosystem
to survive and grow. Students have a grade-appropriate understanding and use of the practices of investigations,
constructing arguments based on evidence, and oral and written communication. They understand that sustaining life
requires substantial energy and matter inputs and that the structure and functions of organisms contribute to the
capture, transformation, transport, release, and elimination of matter and energy. Adding to these crosscutting
concepts is a deeper understanding of systems and system models that ties the performances expectations in this topic together.
Interdependent Relationships in Ecosystems
The Performance Expectations in Interdependent Relationships in Ecosystems help students formulate an answer to the
question, “How do organisms interact with other organisms in the physical environment to obtain matter and energy?
To answer the question, middle school students construct explanations for the interactions in ecosystems and the
scientific, economic, political, and social justifications used in making decisions about maintaining biodiversity
in ecosystems. Students can use models, construct evidence-based explanations, and use argumentation from
evidence. Students understand that organisms and populations of organisms are dependent on their environmental
interactions both with other organisms and with non-living factors. They also understand that the limits of resources
influence the growth of organisms and populations, which may result in competition for those limited resources. Crosscutting
concepts of matter and energy, systems and system models, and cause and effect are used by students to support
understanding the phenomena they study.
Natural Selection and Adaptations
The Performance Expectations in Natural Selection and Adaptations help students formulate answers to the
questions: “How does genetic variation among organisms in a species affect survival and reproduction? How does
the environment influence genetic traits in populations over multiple generations?” Middle school students
can analyze data from the fossil record to describe evidence of the history of life on Earth and can construct
explanations for similarities in organisms. They have a beginning understanding of the role of variation in
natural selection and how this leads to speciation. They have a grade-appropriate understanding and use of
the practices of analyzing graphical displays; using mathematical models; and gathering, reading, and communicating
information. The crosscutting concept of cause and effect is central to this topic.
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