HS.LS2.1

**Use mathematical and/or computational representations to support explanations of factors that affect carrying
capacity of ecosystems at different scales. **
*[Clarification Statement: Emphasis is on quantitative analysis and comparison of the relationships among interdependent factors including boundaries, resources, climate, and competition. Examples of mathematical comparisons could include graphs, charts, histograms, and population changes gathered from simulations or historical data sets.] [Assessment Boundary: Assessment does not include deriving mathematical equations to make comparisons.]*

HS.LS2.2

**Use mathematical representations to support and revise explanations based on evidence about factors affecting
biodiversity and populations in ecosystems of different scales. **
*[Clarification Statement: Examples of mathematical representations include finding the average, determining trends, and using graphical comparisons of multiple sets of data.] [Assessment Boundary: Assessment is limited to provided data.]*

HS.LS2.3

**Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic
and anaerobic conditions. **
*[Clarification Statement: Emphasis is on conceptual understanding of the role of aerobic and anaerobic respiration in different environments.] [Assessment Boundary: Assessment does not include the specific chemical processes of either aerobic or anaerobic respiration.]*

HS.LS2.4

**Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.**
*[Clarification Statement: Emphasis is on using a mathematical model of stored energy in biomass to describe the transfer
of energy from one trophic level to another and that matter and energy are conserved as matter cycles and energy flows through ecosystems. Emphasis is on atoms and molecules such as carbon, oxygen, hydrogen and nitrogen being conserved as they move through an ecosystem.] [Assessment Boundary: Assessment is limited to proportional reasoning to describe the cycling of matter and flow of energy.]*

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HS.LS2.5

**Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among
the biosphere, atmosphere, hydrosphere, and geosphere.**
*[Clarification Statement: Examples of models could include simulations and mathematical models.] [Assessment Boundary: Assessment does not include the specific chemical steps of photosynthesis and respiration.]*

HS.LS2.6

**Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem. **
*[Clarification Statement: Examples of changes in ecosystem conditions could include modest biological or physical changes, such as moderate hunting or a seasonal flood; and extreme changes, such as volcanic eruption or sea level rise.]*

HS.LS2.7

**Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.* **
*[Clarification Statement: Examples of human activities can include urbanization, building dams, and dissemination of invasive species.]*

HS.LS2.8

**Evaluate the evidence for the role of group behavior on individual and species’ chances to survive and reproduce.**
*[Clarification Statement: Emphasis is on: (1) distinguishing between group and individual behavior, (2) identifying evidence supporting the outcomes of group behavior, and (3) developing logical and reasonable arguments based on evidence. Examples of group behaviors could include flocking, schooling, herding, and cooperative behaviors such as hunting, migrating, and swarming.]*