LEARNING PATHWAYS · MR. ALEXANDER’S CLASS
Learn and review the knowledge and skills in the seventh-grade standards. Each pathway focuses on a learning target with explanations, examples, and practice to help you check your understanding.

SEVENTH-GRADE STANDARDS
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MS-LS4-6 • Use proportions and graphs to explain how trait frequencies can change across generations through natural selection.
Open pathway → Math • The Number SystemAdd and subtract positive and negative rational numbers using models and properties.
Open pathway → Science • Evolution & EvidenceMS-LS4-2 • Use anatomical similarities and differences in modern and fossil organisms to explain evolutionary relationships.
Open pathway → Math • Geometry7.G.5 • Write and solve equations using complementary, supplementary, vertical, and adjacent angles.
Open pathway → Math • Geometry7.G.6 • Solve area, surface area, and volume problems involving polygons, cubes, right prisms, and composite figures.
Open pathway → Science • Natural SelectionMS-LS4-5 • Synthesize reliable information about selective breeding and genetic technologies that influence inherited traits.
Open pathway → Science • EcosystemsMS-LS2-5 • Evaluate competing solutions for protecting biodiversity and ecosystem services using evidence and constraints.
Open pathway → Science • Cells & Body SystemsMS-LS1-3 • Use evidence to argue that the body is made of interacting subsystems built from cells, tissues, and organs.
Open pathway → Science • Cells & Body SystemsMS-LS1-2 • Develop and use a model showing how cell parts contribute to the functioning of the whole cell.
Open pathway → Science • Cells & Body SystemsMS-LS1-1 • Plan and conduct an investigation that provides evidence that living organisms consist of one or more cells.
Open pathway → Math • Geometry7.G.4 • Use circle area and circumference formulas and explain informally why area equals πr².
Open pathway → Science • Engineering for Life ScienceMS-ETS1-2 • Systematically evaluate competing design solutions against the same criteria and constraints.
Open pathway → Math • Statistics & Probability7.SP.3 • Compare overlapping data distributions and describe the difference in centers in units of variability.
Open pathway → Math • Statistics & Probability7.SP.2 • Use random samples to estimate population values and examine how estimates vary across repeated samples.
Open pathway → Math • Statistics & Probability7.SP.8 • Represent compound sample spaces and use lists, tables, tree diagrams, and simulations to find probabilities.
Open pathway → Math • Proportional RelationshipsRecognize one proportional relationship in different forms.
Open pathway → Math • Proportional RelationshipsFind and interpret the multiplier k.
Open pathway → Math • Geometry7.G.3 • Describe the two-dimensional shape made by slicing a three-dimensional prism or pyramid.
Open pathway → Science • Engineering for Life ScienceMS-ETS1-1 • Define a precise life science design problem with measurable criteria, constraints, and environmental considerations.
Open pathway → Science • Genetics & HeredityTracking two genes while checking whether independent assortment is a reasonable model.
Open pathway → Science • Genetics & HeredityHow allele interactions affect phenotype—and what “dominant” does not mean.
Open pathway → Math • Geometry7.G.2 • Construct triangles from stated conditions and explain whether they make one triangle, several triangles, or no triangle.
Open pathway → Science • EcosystemsMS-LS2-4 • Construct an evidence-based argument explaining how physical or biological ecosystem changes affect populations.
Open pathway → Science • Evolution & EvidenceMS-LS4-3 • Compare pictorial patterns of embryological development to infer relationships not obvious in adults.
Open pathway → Science • EcosystemsMS-LS2-3 • Model matter cycling and energy flow among living and nonliving parts of an ecosystem.
Open pathway → Math • Statistics & Probability7.SP.6 • Estimate probability using long-run relative frequency and predict approximate counts.
Open pathway → Science • Matter & Energy in OrganismsMS-LS1-7 • Model how food molecules are rearranged to support growth and release energy as matter moves through an organism.
Open pathway → Science • Evolution & EvidenceMS-LS4-1 • Analyze fossil patterns to explain the existence, change, diversity, and extinction of organisms over time.
Open pathway → Science • Genetics & HeredityHow sections of DNA and their different versions contribute to inherited variation.
Open pathway → Science • Genetics & HeredityMS-LS3-1 • Develop a gene-to-protein model explaining how mutations can have harmful, beneficial, or neutral effects.
Open pathway → Science • Genetics & HeredityHow DNA differences arise and contribute to diversity, health, and evolution.
Open pathway → Science • Genetics & HeredityReading and interpreting an organism’s allele combination.
Open pathway → Math • Proportional RelationshipsSee constant rates as straight lines through the origin.
Open pathway → Science • Genetics & HeredityClassifying allele pairs and connecting them to inheritance predictions.
Open pathway → Science • Genetics & HeredityTwo inheritance patterns that go beyond a simple dominant–recessive model.
Open pathway → Science • EcosystemsMS-LS2-2 • Explain and predict patterns of competition, predation, and mutually beneficial interactions across ecosystems.
Open pathway → Math • Statistics & Probability7.SP.4 • Use center and variability from random samples to make cautious comparisons between two populations.
Open pathway → Science • Genetics & HeredityHow controlled crosses and careful counting revealed basic inheritance patterns.
Open pathway → Science • Engineering for Life ScienceMS-ETS1-4 • Develop a model, generate test data, and use repeated testing to refine a life science design.
Open pathway → Science • Genetics & HeredityUsing one gene at a time to predict possible offspring genotypes and phenotypes.
Open pathway → Math • Expressions & EquationsSolve multi-step real-life and mathematical problems with rational numbers and assess reasonableness.
Open pathway → Math • The Number SystemMultiply and divide positive and negative rational numbers and interpret quotients.
Open pathway → Science • Natural SelectionMS-LS4-4 • Explain using evidence and probabilities why heritable variation affects survival and reproduction in a particular environment.
Open pathway → Science • Genetics & HeredityHow heritable variation and differential reproduction change populations over generations.
Open pathway → Science • Genetics & HeredityUsing family diagrams to trace inheritance patterns while respecting uncertainty and privacy.
Open pathway → Math • Proportional RelationshipsConnect fractions, decimals, and percentages to “per 100.”
Open pathway → Science • Genetics & HeredityHow genes, development, and environment contribute to observable characteristics.
Open pathway → Science • Matter & Energy in OrganismsMS-LS1-6 • Use evidence to explain how photosynthesis moves matter and transfers light energy into stored chemical energy.
Open pathway → Science • Growth & ReproductionMS-LS1-5 • Explain with evidence how genetic differences and environmental conditions can influence organism growth.
Open pathway → Math • Statistics & Probability7.SP.5 • Interpret probability between 0 and 1 as a measure of likelihood.
Open pathway → Science • Genetics & HeredityPredicting the chance of inheritance outcomes without treating chance as a guarantee.
Open pathway → Math • Statistics & Probability7.SP.7 • Build uniform and nonuniform probability models and compare predictions with observed frequencies.
Open pathway → Math • Proportional RelationshipsSelect, solve, and explain proportional models in complex situations.
Open pathway → Math • Proportional RelationshipsUse rows and columns to find a constant multiplier.
Open pathway → Math • Proportional RelationshipsIdentify starting values, changing rates, and misleading patterns.
Open pathway → Math • The Number SystemSolve real-world and mathematical problems involving all four operations with rational numbers.
Open pathway → Math • Proportional RelationshipsUse multiplication and division to preserve the same comparison.
Open pathway → Math • Proportional RelationshipsUse unit rates to make fair decisions.
Open pathway → Math • Proportional RelationshipsDecide whether two quantities change by the same multiplier.
Open pathway → Science • Growth & ReproductionMS-LS1-4 • Use empirical evidence to explain how animal behaviors and plant structures affect reproductive success.
Open pathway → Science • EcosystemsMS-LS2-1 • Analyze data to explain how resource availability affects organism growth and population size.
Open pathway → Math • Expressions & EquationsRewrite expressions in different forms to reveal useful information about a problem.
Open pathway → Math • Statistics & Probability7.SP.1 • Identify a population, choose a representative sample, and explain why random sampling supports valid inferences.
Open pathway → Math • GeometryUse proportional relationships to connect models and real objects.
Open pathway → Science • Cells & Body SystemsMS-LS1-8 • Synthesize reliable information explaining how sensory receptors send information to the brain for responses or memories.
Open pathway → Science • Genetics & HeredityHow genes on sex chromosomes can create distinctive inheritance patterns.
Open pathway → Science • Genetics & HeredityMS-LS3-2 • Model why asexual reproduction generally preserves genetic information while sexual reproduction creates new combinations.
Open pathway → Math • Proportional RelationshipsConnect a graph’s steepness to its constant of proportionality.
Open pathway → Math • Expressions & EquationsUse variables to represent quantities and solve equations and inequalities from real situations.
Open pathway → Math • Proportional RelationshipsUse equivalent ratios, unit rates, and equations strategically.
Open pathway → Science • Genetics & HeredityHow characteristics pass from parents to offspring—and why genes are only part of the story.
Open pathway → Math • Proportional RelationshipsFind how much for exactly one unit.
Open pathway → Science • Engineering for Life ScienceMS-ETS1-3 • Analyze design-test data and combine the strongest useful features into an improved solution.
Open pathway → Math • Expressions & EquationsUse properties of operations to add, subtract, factor, and expand linear expressions.
Open pathway → Math • Proportional RelationshipsRepresent proportional relationships with algebra.
Open pathway →Learning target: compare prices by calculating the cost of one ounce.
Which bag costs less per ounce?
Divide price and ounces by the same quantity to scale each comparison to one ounce. Bag B has the lower unit price.
A 12-ounce bag costs $5.40. Calculate its unit price. Where does it fit between Bags A and B?
$5.40 ÷ 12 = $0.45 per ounce. Its unit price is lower than A and higher than B.
Explain: “I compared ___ per ___ because ___. My evidence is ___.”
Learning target: explain how inherited variation and differences in reproductive success can change a population.
Birds more easily spot light beetles on dark ground. If color is inherited, what could happen over generations?
Dark beetles initially make up 5/10 = 50%. In this possible offspring generation they make up 8/12 ≈ 67%. Their proportion increased.
The model assumes inherited color and equal offspring numbers per survivor. Real outcomes vary. Survival contributes to evolutionary change through reproduction.
If the ground becomes light, what evidence would you need to predict a change?
Check whether light beetles now survive and reproduce more successfully, whether color remains heritable, and whether other factors affect reproduction. A changed background alone does not guarantee an outcome.
Success check: identify the original variation, compare proportions, and connect survival with reproduction.