• Middle School Science Grade 7/8 Semester 4

    Grade: 7/8
    Timeline: 18 weeks
    Title:  Ecosystems: Matter and Energy Flow in Organisms

    Unit Overview: In this unit, students will expand on their abilities to understand scientific inquiry.  They will think critically to make connections between claims and evidence. Students will develop their understanding of populations and ecosystems, including studies of populations and food webs.  Students will consider abiotic and biotic factors in the population studies.  Reproduction and heredity will be studied, as well as diversity and adaptations of organisms.  Understanding of environmental changes will be considered.

     Unit Objectives: The objectives of this unit are to apply the Next Generation Science Standard (NGSS) Crosscutting Concepts that bridge disciplinary boundaries, uniting core ideas throughout the fields of science and engineering.
    1. Cause and Effect.  Cause and effect relationships may be used to predict phenomena in natural systems.  Phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.
    2. Scale, Proportion, and Quantity.  Phenomena that can be observed at one scale may not be observable at another scale.
    3. Systems and System Models.  Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems.
    4. Energy and Matter.  Matter is conserved because atoms are conserved in physical and chemical processes.  Within a natural system, the transfer of energy drives the motion and/or cycling of matter.  The transfer of energy can be tracked as energy flows through a natural system.
    5. Structure and Function.  Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function.
    6. Patterns. Patterns can be used to identify cause and effect relationships.   Graphs, charts, and images can be used to identify patterns in data.
    7. Stability and Change.  Small changes in one part of a system might cause large changes in another part. 

     Focus Standards:
    S8.A.1.2.1  Describe the positive and negative, intended and unintended, effects of specific scientific results or technological developments (e.g., genetic engineering).
    S8.A.1.2.2  Identify environmental issues and explain their potential long-term health effects (e.g., pollution pest controls, vaccinations).
    S8.A. 1.2.3  Describe fundamental scientific or technological concepts that could solve practical problems (e.g., Mendelian genetics).
    S8.A.1.3.2  Use evidence, observations or explanations to make inferences about change in systems over time (e.g., carry capacity).
    S8.A.1.3.3  Examine systems changing over time, identifying the possible variables causing this change, and drawing inferences about how these variables affect this change.
    S8.A.1.3.4  Given a scenario, explain how a dynamically changing environment provides for the sustainability of living systems.
    S8A.2.2.3  Describe ways technology (e.g., microscope) extends and enhances human abilities for specific purposes.
    S8.A.3.1.2  Explain the concept of order in a system (e.g., trophic levels).
    S8.A.3.1.4  Distinguish between open loop (e.g., energy flow, food web) and closed loop (e.g., materials in the nitrogen and carbon cycles).
    S8.A.3.2.1  Describe how scientists use models to explore relationships in natural systems (e.g., an ecosystem).
    S8.A.3.2.3  Given a model showing simple cause-and-effect relationships in a natural system, predict results that can be used to test the assumptions in the model (e.g., photosynthesis).
    S8.A.3.3.2  Describe repeating structure patterns in nature or periodic patterns.
    S8.B.1.1.1 Describe the structures of living things that help them function effectively in specific ways.
    S8.B.2.1.1 Explain how inherited structures or behaviors help organisms survive and reproduce in different environments.
    S8.B.2.1.2 Explain how different adaptions in individuals of the same species may affect survivability or reproduction success.
    S8.B.2.1.3 Explain that mutations can alter a gene and are the original source of new variations.
    S8.B.2.1.4 Describe how selective breeding or biotechnology can change the genetic makeup of organisms.
    S8.B.2.1.5 Explain that adaptations are developed over long periods of time and are passed from one generation to another.
    S8.B.2.2.1 Identify and explain differences between inherited and acquired traits.
    S8.B.2.2.2 Recognize that the gene is the basic unit of inheritance, that there are dominant and recessive genes, and that traits are inherited.
    S8.B.3.1.1 Explain the flow of energy through an ecosystem (e.g., food chains, food webs).
    S8.B.3.1.2 Identify major biomes and describe abiotic and biotic components (e.g., abiotic: different soil types, air, water,sunlight; biotic: soil microbes,decomposers).
    S8.B.3.1.3 Explain relationships among organisms (e.g., producers/consumers, predator/prey) in an ecosystem.
    S8.B.3.2.1 Use evidence to explain factors that affect changes in populations (e.g., deforestation, disease, land use, natural disaster, invasive species).
    S8.B.3.2.2 Use evidence to explain how diversity affects the ecological integrity of natural systems.
    S8.B.3.2.3 Describe the response of organisms to environmental changes (e.g., changes in climate, hibernation, migration, coloration) and how those changes affect survival.
    S8.B.3.3.1 Explain how human activities may affect local, regional, and global environments.
    S8.B.3.3.4 Explain how long-term effects of using integrated pest management (e.g., herbicides, natural predators, biogenetics) on the environment.
    NGSS Disciplinary Core Ideas
             LS1.A:  Structure and Function
    • All living things are made up of cells, which is the smallest unit that can be said to be alive.  An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular).
    • Within cells, special structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell.
    • In multicellular organisms, the body is a system of multiple interacting subsystems.  These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body function.
             LS1.B: Growth and Development of Organisms
    • Animals engage in characteristic behaviors that increase the odds of reproduction.
    • Plants reproduce in a variety of ways, sometimes depending on animal behavior and specialized features for reproduction.
    • Genetic factors as well as local conditions affect the growth of the adult plant.
           LS1.C:  Organization for Matter and Energy Flow in Organisms
    • Plants, algae (including phytoplankton), and many microorganisms use the energy from light to make sugars (food) from carbon dioxide from the atmosphere and water through the process of photosynthesis, which also releases oxygen.  These sugars can be used immediately or stored for growth or later use. 
    • Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy.
           PS3.D:  Energy in Chemical Processes and Everyday Life.
    • The chemical reaction by which plants produce complex food molecules (sugars) requires an energy input (i.e., from sunlight) to occur.  In this reaction, carbon dioxide and water combine to form carbon-based organic molecules and release oxygen. 
    • Cellular respiration in plants and animals involve chemical reactions with oxygen that release stored energy.  In these processes, complex molecules containing carbon react with oxygen to produce carbon dioxide and other materials.
          LS2.A:  Interdependent Relationships in Ecosystems
    • Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors.
    • In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction.
    • Growth of organisms and population increases are limited by access to resources.
    • Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations or organisms.  Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival.  Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared.

    Concepts - Students will know:
    • About scientific inquiry and be able to demonstrate the abilities to do scientific inquiry.
    • Living things undergo fundamental life processes;an organism is a complete living thing.
    • How abiotic factors affect organisms.
    • That organisms can be categorized by the role they serve in an ecosystem.
    • How matter and energy cycle through the ecosystem.
    • The importance of biodiversity for the survival of the species and well-being of the ecosystem.
    • How reproduction is essential to the continuation of life forms.
    • That traits of an organism are carried on one or more genes located in the chromosome.
    • How genes affect the traits that are passed from parent to offspring.
    • How genetic information can be expressed.
    Competencies -Students will be able to:
    • Explain current scientific knowledge, models and understanding that guide scientific investigations.
    • Use appropriate tools, and techniques to gather, analyze and interpret data.
    • Define organism.
    • Distinguish between living and non-living things.
    • Identify abiotic factors in an environment.
    • Observe ecosystems over time.
    • Investigate how varying abiotic factors affect organisms.
    • Examine the role of producers, consumers and decomposers.
    • Construct food webs for various ecosystems.
    • Analyze interactions of organisms within an ecosystem (e.g. predator/prey, etc).
    • Demonstrate how energy from the sun flows through food webs.
    • Identify cycles in an ecosystem (food, water, etc).
    • Classify organisms by their characteristics.
    • Explore challenges for survival of species and ecosystems (pollution, invasive species, disease, etc)>
    • Examine how different adaptations have allowed organisms to survive in their environment.
    • Compare and contrast reproduction and life cycles of different organisms.
    • Explain that chromosomes are located in the nucleus.
    • Show that a pair of chromosomes is needed for a trait to be expressed (allele).
    • Apply Mendelian concepts of genetics (dominant/recessive, independent and segregation).
    • Review Mendel's contribution to genetics.
    • Demonstrate how genes combine to determine characteristics.
    • Describe mutation's effects on a trait's expression.

    Formative assessments
    •  Informal notes
    • Teacher observation
    • Quick writes
    • Response sheets
    Summative Assessments
    • Mid-summative Assessments; Investigations 1-2; 3,4,5,6,7,8,9
    • Final Summative Assessment
    • Post-assessment

    Elements of Instruction:
    The NGSS identifies eight Science and Engineering Practices that all students in all grades must participate in to effectively investigate the natural world through the practices of science inquiry, or solve meaningful problems through the practices of engineering design.
    Science and Engineering Practices
    Practice 1 Asking Questions and Defining Problems
    Students should be able to ask questions of each other about the texts they read, the features of the phenomena they observe, and the conclusions they draw from their models or scientific investigations. For engineering, they should ask questions to define the problem to be solved and to elicit ideas that lead to the constraints and specifications for its solution.
    Practice 2 Developing and Using Models
    Modeling can begin with students’ models progressing from concrete “pictures” and/or physical scale models  to more abstract representations of relevant relationships in later grades, such as a diagram representing forces on a particular object in a system.

    Practice 3 Planning and Carrying Out Investigations
    Students should have opportunities to plan and carry out several different kinds of investigations. They should engage in investigations that range from those structured  by the teacher—in order to expose  an issue or question that they
    would be unlikely to explore on their own—to those that emerge from students’ own questions.
    Practice 4 Analyzing and Interpreting Data
    Once collected, data must be presented in a form that can reveal any patterns and relationships and that allows results to be communicated to others. Because raw data as such have little meaning, a major practice of scientists is to organize and interpret data through tabulating, graphing, or statistical analysis. Such analysis can bring out the meaning of data—and their relevance—so that they may be used as evidence.
    Practice 5 Using Mathematics and Computational Thinking
    Although there are differences in how mathematics and computational thinking are applied in science and in engineering, mathematics often brings these two fields together by enabling engineers to apply the mathematical form of scientific theories and by enabling scientists to use powerful information technologies designed by engineers. Both can thereby accomplish investigations and analyses and build complex models, which might otherwise be out of the question. Students will practice these computations.
    Practice 6 Constructing Explanations and Designing Solutions
    The goal of science is to construct explanations for the causes of phenomena. Students are expected to construct their
    own explanations, as well as apply standard explanations they learn about from their teachers or reading.
    Practice 7 Engaging in Argument from Evidence
    The study of science and engineering should produce a sense of the process of argument necessary for advancing and defending a new idea or an explanation of a phenomenon and the norms for conducting such arguments. In that spirit, students should argue for the explanations they construct, defend their interpretations of the associated data, and advocate
    for the designs they propose.
    Practice 8 Obtaining, Evaluating, and Communicating Information
    Any education in science and engineering needs to develop students’ ability to read and produce domain-specific text. As such, every science or engineering lesson is in part a language lesson, particularly reading and producing the genres of texts that are intrinsic to science and engineering.

    Investigation 1: Maintain a milkweed-bug colony
    Investigation 3:  Localize mini-ecosystems
                           Observe effects of a decomposer
    Investigation 5:  Diagram humans in food webs
                           Describe human trophic levels
    Investigation 6:  Discuss other population limitations
    Investigation 7:  Investigate local ecosystem issues
    Investigation 10:  Use walkingsticks simulation 

     Interdisciplinary Connections:
    Language Arts:
       Reading critically in content area
       Academic and content specific vocabulary
       Measurement activities

     Additional Resources / Games: