Clue 1: Orient yourself
Which station is the first place unfinished work appears?
Use the labels and the picture's left-to-right, near-to-far, or before-and-after order. Name only what you can point to.
The question
Why can the same kind of opening come from several different failed steps?
Why it matters: The face forms through a timed sequence of growth, movement, and joining. Locating the missed step helps researchers ask a testable question instead of treating every cleft as the same process. Today you practice the professional reasoning behind that work: A cleft pattern narrows the failed developmental checkpoint, but it rarely identifies one unique cause.
On your WebXam
Distinguishing a local fusion failure from a broad patterning defect
For life
One result can have many causes; the outcome alone never tells you which.
Principle: Many roads, one ending
Five principles we return to
Having it is not using it
Same instructions, different switches
Same look, different cause
Change one thing and watch
Boss or doorman?
Decides the result or only allows it
Held down, not gone
Remove the brake and it returns
Many roads, one ending
One result can begin many ways
Try the everyday version first
A stopped assembly line reveals a checkpoint, not the culprit
An assembly line is a series of stations where each station completes one part of a larger job. A checkpoint is a place where workers inspect the item before it moves on. Finding unfinished work at one checkpoint shows where the line stopped, but it does not name the failed part. A power loss, jam, late supply, or damaged tool can all leave work at the same station.
Do not jump to the biology yet. Treat the picture as a small system. Track its parts, follow one change at a time, and keep more than one explanation open until the picture supplies a way to separate them.
Clue 2: Trace one change
Can several failures stop the line at the same station?
Follow one object, stage, or path. Point to the first place where the situation changes instead of jumping to the ending.
Clue 3: Keep the cause open
What extra evidence is needed to identify the cause?
List more than one explanation that still fits. Name the extra observation that would help you separate those possibilities.
Now inspect the illustration
Work from the visible evidence. A useful answer names the part of the picture that supports it and leaves unknown causes open.
- 1Which station is the first place unfinished work appears?
- 2Can several failures stop the line at the same station?
- 3What extra evidence is needed to identify the cause?
Tier 1 check
Finish with the everyday model
Use the everyday picture to answer today's question in plain words: Why can the same kind of opening come from several different failed steps?
You can complete today's required check without opening the technical details below.
Ready for the real names? Optional tier 2
Technical rules and limits
Rule 1: Work backward to the earliest failed checkpoint.
Rule 2: Different causes can create a similar endpoint.
Rule 3: What you can see locates a process better than one tiny part does.
Where the analogy stops: Development is a branching network, not a single conveyor belt.
Carry the previous idea forward
IRF6-dependent periderm acts as a temporary non-stick surface that prevents the wrong oral tissues from adhering.
Today's technical takeaway
A cleft pattern narrows the failed developmental checkpoint, but it rarely identifies one unique cause.
Now map the same rules onto biology
Read three cleft patterns backward
Station before the stop
Last developmental step completed
Stopped station
Failed growth, movement, adhesion, or fusion checkpoint
Fault investigation
Genetic, environmental, and model evidence
Educational illustration, not a clinical photograph. Use the labels and evidence cards to make the biological claim.
Mateo's case file: evidence supplied in this lesson
DEV14-E1
Cleft lip points to an early upper-lip growth and fusion boundary.
Why it matters: The phenotype localizes an early facial checkpoint.
DEV14-E2
Cleft palate can result from failed shelf growth, elevation, adhesion, or seam removal.
Why it matters: Several mechanisms share the palate endpoint.
DEV14-E3
Mateo has both cleft lip and palate.
Why it matters: His pattern spans connected but distinguishable developmental events.
Make the clinical decision
You are triaging three cases for a developmental review board.
Case A has cleft lip only. Case B has cleft palate only. Mateo has both.
AAssign each pattern to the narrowest supported checkpoint list.
BAssign one gene to each pattern from anatomy alone.
CTreat all three patterns as the same developmental event.
Choose the triage method and explain why the palate list remains broader.
Evidence required
DEV14-E1 + DEV14-E2 Claim ceiling
You may narrow checkpoints from anatomy. You may not assign one unique molecular cause from phenotype alone.Go deeper Optional tier 3
Everything required for today is above. Open these only if you want the explainer, source trail, or download files.
The everyday model and Tier 1 check are the complete required path for this lesson.
Use these checks to keep your place. They are not turned in through the portal.
Check off as you finish
- Worked through the everyday picture and answered its three questions.
- Completed the Tier 1 check in plain words.
Turn in: Developmental lesson 14: Mapping the Failure, Which Step Breaks for a Cleft Lip Versus a Cleft Palate
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Optional legacy technical materials Open only if you want the original notes, vocabulary, artifact, and CER work
Before this page, you should know
- The is a single flat layer of cells that wraps embryonic skin and mouth lining and acts as a controlled non-stick coating.
- At true sites the peels away on cue so the layers underneath can join; elsewhere it keeps wrong surfaces apart.
Today's new idea is only
Because we know the normal build sequence, a phenotype can be read backward to the single step that failed, and a one-site cleft with nothing else wrong points to a local rather than a body-wide .
Goal: Map a phenotype back to the exact developmental step that failed, and distinguish a single local from a broad, multi-step .
Know by the end
- The normal build order is: week 4 to 6 lip , week 6 shelf growth, week 8 shelf elevation, weeks 8 to 12 shelf and fusion.
- A lip points to a failure of step 1 (medial nasal plus maxillary ); a cleft only points to a failure of palate growth, elevation, or fusion.
- A means the body plan is normal but one seam did not close; a mis-sets the whole body plan so many structures form wrong at once.
- An is limited to one structure with no other anomalies present.
1
Reading a phenotype backward
Model start: A phenotype is the visible result you can observe, here the specific . Because we know the normal build sequence, we can read a phenotype backward to the broken step.
- A lip points to a failure of ____ (step 1, lip of medial nasal plus maxillary processes) in weeks 4 to 6.
- A only points to a failure of one of the steps: ____ (growth, elevation, or ) in weeks 6 to 12.
2
Fusion failure vs patterning defect
- A ____ () is when the building blocks are present and the body plan is normal but one specific seam did not close.
- A ____ () is broader: the whole body plan is mis-set so many structures form wrong at once.
- When a defect is limited to one structure with no other anomalies, we call it an ____ (isolated) defect.
Everything you need for today is on this page. These links are optional.
What to read
Read the short plain-language explanation written for this lesson. Plain-language explainer for this lesson
Why this source matters
This explanation gives you the background for today's idea without making you decode a research paper: Because we know the normal build sequence, a phenotype can be read backward to the single step that failed, and a one-site cleft with nothing else wrong points to a local rather than a body-wide .
Words to unlock first
Reading moves
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Stop point
Stop after the final 'Use it now' section. The research citations are available separately for advanced readers.
Your output
Write one claim-evidence sentence: state the main idea, then name the example or evidence that supports it.
Where this fits
Tested on (Ohio WebXam)
Genetics of Disease · 072130
PLTW lesson
MI · Developmental domain · PLTW PBS 072110
WebXam domain
Molecular and Genetic Technology
Evidence to produce
Open Mateo's case summary: a complete cleft of the lip and palate on the left side, and a newborn exam that found no other birth defects. Write three sentences: (1) which step or steps his cleft points to, (2) whether his pattern looks more like an isolated local fusion failure or a body-wide patterning defect, and (3) what evidence in his exam supports your answer. Do not name a diagnosis; just map the failure and classify the pattern.
Lab / skill
Principles of Biomedical Science (PBS)
Everything required for today's decision is already in the case file and plain-language explainer. The links below are original papers and database records for teachers and advanced readers, not assigned student reading.
- Claim: Mateo's finding looks like an isolated, local rather than a body-wide .
- Evidence: His record shows a of the lip and and ____ other birth defects.
- Reasoning: Because a would usually disturb ____ structures at once, a single with everything else normal fits a ____ failure better.
How this is graded (rubric)
For: Open Mateo's case summary: a complete cleft of the lip and palate on the left side, and a newborn exam that found no other birth defects. Write three sentences: (1) which step or steps his cleft points to, (2) whether his pattern looks more like an isolated local fusion failure or a body-wide patterning defect, and (3) what evidence in his exam supports your answer. Do not name a diagnosis; just map the failure and classify the pattern.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in through the route named under Submit here and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
How the model answer scores against this rubric
- CompleteProficient: Nothing is left blank: the model fills every part of "Open Mateo's case summary: a complete cleft of the lip and palate on the left side, and a newborn exam that found no other birth defects. Write three sentences: (1) which step or steps his cleft points to, (2) whether his pattern looks more like an isolated local fusion failure or a body-wide patterning defect, and (3) what evidence in his exam supports your answer. Do not name a diagnosis; just map the failure and classify the pattern.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be attached to your class form or handed in, and confirmed.
What's next: We can now map which step failed and see that Mateo's looks like an isolated . But mapping a failure is not fixing it. Each step happens in a narrow calendar window. Is there a moment after which the step can no longer be repaired, so the becomes locked in?