Pedigree and risk CER
Do now
Students construct a CER linking pedigree evidence to a calculated genetic risk for an offspring.
- Hand in
- Written CER with a quantitative genetic-risk claim, pedigree and Punnett square evidence, and at least one stated limitation.
- Where
- Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
You get two school days for every day you were absent, so this deadline moves with you.
Given this family's pedigree, what exact probability can you defend that the couple's next child will be affected, and what assumption is that number resting on?
Students construct a CER linking pedigree evidence to a calculated for an offspring.
- • Calculate offspring risk consistent with the pedigree and inheritance pattern.
- • Write a CER with claim, quantitative evidence, and reasoning that cites at least one limitation.
- What do a filled-in square and a filled-in circle mean on a standard pedigree?
- If both parents are Aa for a recessive disease, what fraction of their children are expected to be affected?
- 1Build a pedigree from the case history using standard symbols for sex and affected status.
- 2Trace the inheritance pattern and label carriers across two generations.
- 3Use a Punnett square to estimate the probability that the next child is affected.
- 4Write a claim stating the for the couple.
- 5Support the claim with pedigree evidence and reasoning that names assumptions and limitations.
What did this day actually feel like?
Pedigree and risk CER
We built a pedigree from a case history using the standard symbols, traced the inheritance pattern, labeled carriers across two generations, then used a Punnett square to calculate the probability that the next child is affected.
This is the first CER where the claim is a number. Not "there is a risk" but a specific probability with the pedigree and the square as evidence. Quantifying it instead of estimating it changes the conversation entirely.
My limitation line: a Punnett square gives the probability for each pregnancy independently, so a family that already has an affected child does not have a lower chance next time. That is a genuinely counterintuitive thing and I got it wrong first.
AT HOME, THE NIGHT BEFORE THU OCT 29 Submit tracker and evidence Karyotype, pedigree, and CER assembled into one labeled file, checked against the rubric, with sources cited and unresolved limitations noted in a closing line.
The tracker now asks for a self-assessed confidence rating. Rating my own confidence honestly is harder than doing the work. I put myself lower on pedigrees than on karyotypes, which is accurate and tells him where I need help.
Turned in: full genetic-risk package → recorded in Class Records
Fiction. There is no such student. The lessons, labs and dates are the real planned course; the student, the classmates and the conversations are invented.
The same day, drawn.
First CER where the claim is a number. A Punnett square gives the probability for each pregnancy independently, which is genuinely counterintuitive.
Fiction. There is no such student. The lessons, labs and dates are the real planned course; the student, the classmates and the conversations are invented.
🛠 Get unstuck · pick your level
🔑 Today's words · 5
Tap a word in the lesson for a plain meaning and one example. Recycled into next week's Do-Now.
Do the work · 80-minute blockfirst 5 min = hook▸
💡 Big idea: A pedigree feeds parental genotypes into a Punnett square, so a family's history becomes a quantified probability instead of a rough estimate.
- 0-8 minWarm-up: draw pedigree symbols for affected male, female, unaffected female.
- 8-25 minBuild the two-generation pedigree from the case history; label carriers.
- 25-40 minTrace inheritance pattern; set up and complete the Punnett square.
- 40-60 minWrite the CER: claim with % risk, pedigree + Punnett square evidence, reasoning.
- 60-72 minAdd one assumption and one limitation to the CER reasoning section.
- 72-80 min: swap and check that claim is quantitative and evidence is cited.
- • Yesterday you identified a chromosomal abnormality; today you calculate how likely it is to appear in the next generation.
- • Pedigrees and Punnett squares are the two core tools of classical genetics on the WebXam 072110 Biotechnology strand.
- • Your CER today must include a number, a percent risk, not just a direction.
- • Label carriers as well as affected individuals, most families have carriers who never show symptoms.
- • Standard pedigree symbols encode sex, affected status, and status across generations.
- • A Punnett square converts inheritance pattern and parental genotypes into offspring probabilities.
- • A CER requires a quantitative claim, specific pedigree evidence, and a stated assumption or limitation.
Unit 2.2 to 2.3: Chromosomal abnormalities, genetic risk, family evidence, diagnosis from mixed data. · Pedigree and risk CER
Day 4 of this lesson. Open this exact section in myPLTW (find it in Clever, Microsoft sign-in), then do the work below.
Do this: Open myPLTW, find the Lesson 2.2 Decoding a Diagnosis pedigree or genetics-risk activity, and use it to verify your inheritance-pattern determination.
Submit any platform questions related to pedigree reading and Punnett square probability.
You identified the chromosomal abnormality Wednesday. Finish platform questions before moving to CER writing so your pedigree interpretation is grounded in the lesson.
Platform submission plus your handwritten or digital CER serve as dual evidence.
The official PLTW activity stays inside myPLTW. If myPLTW will not open, use F1 and E1-E3 on this page to complete today's local evidence decision, then make up the official activity when access returns. Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible through the submission route shown below.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Unit 2.2 to 2.3: Chromosomal abnormalities, genetic risk, family evidence, diagnosis from mixed data. · Pedigree and risk CER
Open myPLTW, find the Lesson 2.2 Decoding a Diagnosis pedigree or genetics-risk activity, and use it to verify your inheritance-pattern determination.
You identified the chromosomal abnormality Wednesday. Finish platform questions before moving to CER writing so your pedigree interpretation is grounded in the lesson.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Students construct a CER linking pedigree evidence to a calculated for an offspring.
- Build a pedigree from the case history using standard symbols for sex and affected status.
- Trace the inheritance pattern and label carriers across two generations.
- Use a Punnett square to estimate the probability that the next child is affected.
- Write a claim stating the for the couple.
- Support the claim with pedigree evidence and reasoning that names assumptions and limitations.
CER: Written CER with a quantitative genetic-risk claim, pedigree and Punnett square evidence, and at least one stated limitation.
Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not. Use the checklist just below and upload by 11:29 PM for full credit. Absent with an excused absence? You get two school days for every day you were absent, so this deadline moves with you.
| Task | Who |
|---|---|
| Build a pedigree from the case history using standard symbols for sex and affected status. | _______ |
| Trace the inheritance pattern and label carriers across two generations. | _______ |
| Use a Punnett square to estimate the probability that the next child is affected. | _______ |
| Write a claim stating the for the couple. | _______ |
| Support the claim with pedigree evidence and reasoning that names assumptions and limitations. | _______ |
Working solo? Put your own name in "Who" for every row.
- Calculate offspring risk consistent with the pedigree and inheritance pattern.
- Write a CER with claim, quantitative evidence, and reasoning that cites at least one limitation.
- 1Do thisStudents construct a CER linking pedigree evidence to a calculated genetic risk for an offspring.
- 2Use this resource
- 3Submit thisCER: Written CER with a quantitative genetic-risk claim, pedigree and Punnett square evidence, and at least one stated limitation.
- 4Submit it here
- 1Open the drop folder.
- 2Sign in with your district Microsoft account, not a personal one.
- 3Upload the file, named Lastname_Firstname__Assignment Title.
- 4Your own upload panel says Uploaded with a green check: that is your receipt.
Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not. Principles of Biomedical Technology (Principles of Biomedical Science) › Unit 2.2 to 2.3: Chromosomal abnormalities, genetic risk, family evidence, diagnosis from mixed data. › CEROpen the drop folder
Learn it · deck, reading, and vocabulary▸
The deck carries the prior idea forward, lets you inspect an analogy, maps the rule to biology, and ends with the same evidence decision and exit ticket used on this page.
Generated from this lesson's canonical data with a red-team citation check.
A is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
A pedigree feeds parental genotypes into a Punnett square, so a family's history becomes a quantified probability instead of a rough estimate.
A detective board holds observations, possible explanations, and one next question.
- Which notes are direct observations?
- Which notes are explanations?
- What new evidence would separate the explanations?
Keep observations separate from explanations, then collect the evidence that can distinguish the options.
Biomedical investigations use controlled procedures and validated measurements, not intuition alone.
- • Board notes map to E1-E3.
- • Possible explanations map to the decision options.
- • The next question maps to the evidence-based action.
Driving question: Given this family's pedigree, what exact probability can you defend that the couple's next child will be affected, and what assumption is that number resting on?
What you already know: A is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
New idea: A pedigree feeds parental genotypes into a Punnett square, so a family's history becomes a quantified probability instead of a rough estimate.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Pedigree and risk CER. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled observation or evidence sequence before choosing an explanation.
- Observe or measure the relevant feature in Pedigree and risk CER.
- Organize the observation with a stable evidence ID.
- Apply this rule: Keep observations separate from explanations, then collect the evidence that can distinguish the options.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: Given this family's pedigree, what exact probability can you defend that the couple's next child will be affected, and what assumption is that number resting on?
What the evidence supports: E1-E3 and F1 support the daily take-home when the response meets the stated success criteria.
What it cannot prove: The package does not support claims beyond this lesson's or any real patient diagnosis.
- • : An organized picture of a person's full set of chromosomes arranged by size and shape, used to spot missing, extra, or rearranged chromosomes.
- • inheritance: The passing of genetic traits from parents to offspring through genes carried on chromosomes during reproduction.
- • : The specific set of gene versions an individual carries, which works with the environment to shape observable traits.
- • phenotype: The observable traits of an organism, such as appearance or function, that result from its combined with environmental influences.
- • : A person who carries one copy of a disease without showing symptoms but can pass it to their children.
- • pedigree: A family tree drawn with standard symbols (squares for males, circles for females, filled for affected) so any geneticist can read a family at a glance.
- • : The increased chance of developing a disease that a person inherits because of specific gene variants passed down in their family.
Use it now: Choose one decision option. Cite E1 and E3, then explain how the rule connects the evidence to your choice.
Go further, optional: The source links below are optional enrichment. Every fact required for today's local evidence decision appears in this lesson package.
Standard pedigree symbols encode sex, affected status, and status across generations.
Limit: E1 supplies context or an observation; it does not by itself establish the explanation.
A pedigree feeds parental genotypes into a Punnett square, so a family's history becomes a quantified probability instead of a rough estimate.
Limit: E2 is a teaching statement or comparison and must be checked against the task evidence.
Calculate offspring risk consistent with the pedigree and inheritance pattern.
Limit: E3 supports only the result or product criterion named here; it cannot justify a broader clinical or causal claim.
PLTW-PBT-2026-10-28 · Simulated classroom evidence scenario
Your role: biomedical investigator
Decision: Your team must decide what the evidence from Pedigree and risk CER supports before submitting the claim-evidence-reasoning response named on the lesson page.
- • Choose the strongest supported explanation.
- • Choose the next evidence to collect.
- • Hold the decision because the evidence is insufficient.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the claim-evidence-reasoning response.
Claim ceiling: The supplied lesson evidence can support an observation, pattern, classroom mechanism, or next-step decision about Pedigree and risk CER. It cannot by itself prove causation, establish a real clinical diagnosis, or justify action outside this classroom task.
Reason for review: Your team must decide what the evidence from Pedigree and risk CER supports before submitting the claim-evidence-reasoning response named on the lesson page.
Context: A pedigree combined with a Punnett square converts family observations into a defensible probability, so risk can be quantified rather than felt.
- • T1: Build a pedigree from the case history using standard symbols for sex and affected status.
- • T2: Trace the inheritance pattern and label carriers across two generations.
- • T3: Use a Punnett square to estimate the probability that the next child is affected.
- • T4: Write a claim stating the for the couple.
- • T5: Support the claim with pedigree evidence and reasoning that names assumptions and limitations.
- • E1: Standard pedigree symbols encode sex, affected status, and status across generations.
- • E2: A pedigree feeds parental genotypes into a Punnett square, so a family's history becomes a quantified probability instead of a rough estimate.
- • E3: Calculate offspring risk consistent with the pedigree and inheritance pattern.
Measurements: Use only the measurements, units, graph, or counts supplied in today's task. No additional patient measurement is implied.
Figure finding: Teaching diagram for Pedigree and risk CER. Trace the labeled observation or evidence sequence before choosing an explanation. This is a teaching model, not patient or experimental data.
Uncertainty: This is a composite classroom scenario. Missing history, measurements, or confirmation tests remain unknown and limit the conclusion.
Mean = sum of values / number of values. Median = middle ordered value. Range = maximum - minimum.
For 2, 4, 4, and 10: mean = 20 / 4 = 5, median = 4, and range = 10 - 2 = 8.
Mean, median, and range keep the measurement unit. Order the values before finding the median.
Calculate the requested summary for today's supplied values, then write what it reveals and what it hides.
Students often think Students often think the 25 percent risk means that out of four children, exactly one will be affected, so if the first three are healthy the fourth must be affected.. The trap: Each pregnancy is an independent 25 percent chance; the previous children do not change the odds for the next one. The trap is treating probability like a quota, which leads families to false certainty about the next child.
Claim: There is a 50% chance that this couple's next son will be colorblind, and a 0% chance that a daughter will be colorblind.
Evidence: Red-green colorblindness is an X-linked recessive trait, so the allele sits on the X chromosome. The pedigree shows that the mother has a colorblind father, which means she inherited one affected X and is a carrier (X^A X^a), while the father has normal color vision (X^A Y). A Punnett square of X^A X^a mother by X^A Y father gives four equally likely children: X^A X^A, X^A X^a, X^A Y, and X^a Y. Among the two possible sons (X^A Y and X^a Y), one is affected, and neither of the two possible daughters is affected because each daughter still inherits at least one normal X^A from the father.
Reasoning: Because the trait is recessive and carried on the X chromosome, a son is affected whenever his single X carries the recessive allele, since he has no second X to mask it, giving 1 of 2 sons affected, or 50%. A daughter would need two recessive alleles to be affected, but the father can only pass a normal X^A, so no daughter in this cross can be colorblind, which is why the daughter risk is 0%. This reasoning assumes the mother is truly a carrier, which the pedigree supports because her father was colorblind and each daughter of a colorblind man must receive his X^a. A limitation is that the pedigree relies on reported vision status rather than a formal color-vision test, so mild cases could be missed or misreported, and confirming the mother's carrier status with genetic testing would make the 50% son estimate more reliable.
| Punnett (Aa x Aa) | A | a |
|---|---|---|
| A | AA | Aa |
| a | Aa | aa |
This model shows the level of evidence and organization needed to complete: A claim-evidence-reasoning paragraph that states a quantitative genetic-risk for an offspring, supports it with pedigree and Punnett square evidence, and names at least one limitation.
- Write one defensible claim.
- Choose specific evidence that supports the claim.
- Explain the scientific rule that connects the evidence to the claim.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: turns in the CER on the class site under the Pedigree CER assignment before the end of the period.
- CER:
- Claim, Evidence, Reasoning: make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure, the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities. Find it in Clever with your Microsoft sign-in, right next to Schoology.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in Pedigree and risk CER. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
Hand-picked readings and interactives for this lesson, from authoritative open organizations and PLTW's own public course outline.
Check yourself · commit, then reveal▸
Claim ceiling for this check: The supplied lesson evidence can support an observation, pattern, classroom mechanism, or next-step decision about Pedigree and risk CER. It cannot by itself prove causation, establish a real clinical diagnosis, or justify action outside this classroom task.
Both parents are carriers (Aa) for an autosomal recessive disease and already have two healthy children. What is the probability their third child is affected, and why?
Write an answer and pick a confidence to unlock the key.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
Go further and get help▸
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
Today is individual work you can do from home: complete the same target above, then submit your CER.
Open the drop folderTurn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
NHGRI: how to read a pedigreeYou've passed Unit 2, so the optional extra-credit track is open. Complete reserved-unit work from home, including virtual labs, for extra credit. Each item shows its correct submission route.
Open the extra-credit track- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedTurned in the right way, on the class site or handed to Mr. Mendoza in class, and confirmed. Not in Schoology: that is where the report-card grade appears later.