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Genetics & Heredity: Predicting Traits

Students learn how traits pass from parents to offspring through genes and alleles — and use a Punnett square to predict the odds of an offspring inheriting a dominant or recessive trait.

Grade 7Genetics55 minutes1 class period5E ModelExplicit teaching4 StandardsCommon Core
Start the Lesson
Lesson at a Glance

Everything you need before the bell rings

Learning Objectives

Students will be able to…

  • ✓Explain genes and alleles.
  • ✓Tell dominant from recessive.
  • ✓Use a Punnett square.
  • ✓Predict genotype and phenotype ratios.
Essential Question

Why might two brown-eyed parents have a blue-eyed child? How can we predict which traits offspring will inherit?

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Lesson Phases
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Vocabulary Terms
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Standards Aligned
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Interactive Task
Punnett Square · Interactive

The Punnett Square

Project this and set each parent’s genotype. The square fills in the possible offspring — and shows the dominant/recessive ratio.

🧬 Set the parents — predict the offspringTry it
Parent 1
Parent 2

The Lesson · 5E Model

55 minutes, five moves

Tap any phase to open the teacher moves and student actions.

1

Engage — Blue-Eyed Surprise

5 min

Two brown-eyed parents, a blue-eyed child — how?

👩‍🏫 Teacher Moves

  • Pose the eye-color puzzle.
  • Introduce hidden traits.
  • Set the goal: genetics.

🎒 Student Actions

  • Consider the puzzle.
  • Wonder how.
  • Predict the idea.
2

Explore — Explore the Cross

12 min

Students investigate.

👩‍🏫 Teacher Moves

  • Send students to the Punnett Square.
  • Set genotypes; read the offspring.
  • Note the ratios.

🎒 Student Actions

  • Set the parents.
  • Read the offspring.
  • Record ratios.
3

Explain — Dominant & Recessive

13 min

Teacher explains.

👩‍🏫 Teacher Moves

  • Define genes, alleles, dominant, recessive.
  • Show how a recessive trait “hides.”
  • Read genotype vs. phenotype.

🎒 Student Actions

  • Learn the terms.
  • Explain hiding traits.
  • Read the ratios.
4

Elaborate — Elaborate — More Crosses

12 min

Apply.

👩‍🏫 Teacher Moves

  • Try different parent crosses.
  • Predict ratios before revealing.
  • Explain a 3:1 result.

🎒 Student Actions

  • Try new crosses.
  • Predict ratios.
  • Explain 3:1.
5

Evaluate — Evaluate — Exit Ticket

5 min

Three quick checks.

👩‍🏫 Teacher Moves

  • Hand out the exit ticket.
  • Look for Punnett reasoning.
  • Collect as formative data.

🎒 Student Actions

  • Do a cross.
  • Give the ratio.
  • Explain recessive.
Standards Alignment

Built to the standards you report on

Aligned to Next Generation Science Standards and Common Core literacy. State-standard crosswalks available on request.

NGSS
MS-LS3-1

Develop a model to describe how changes to genes affect proteins and structure/function.

NGSS
MS-LS3-2

Develop a model to describe why sexual reproduction results in genetic variation.

NGSS
MS-LS4-5

Gather information about influencing the inheritance of desired traits.

CCSS
RST.6-8.7

Integrate visual information with text in a scientific model.

Differentiation

One lesson, every learner

Multilingual Learners

ELL / EMERGING READERS
  • Punnett-square template with color alleles.
  • Sentence frame: “___ is dominant; ___ is recessive.”
  • Use letter tiles for alleles.

Support & Access

IEP / 504
  • Start with one clear trait.
  • Provide a filled example.
  • Focus on dominant “shows,” recessive “hides.”

Stretch & Extend

GIFTED / EARLY FINISHERS
  • Do a two-trait cross.
  • Explain incomplete dominance.
  • Calculate a percentage from a ratio.
Materials

What to gather

  • 📽️Projector / board
  • 📓Science notebooks
  • 💻The Punnett Square
  • 🔤Allele tiles
  • ✏️Pencils
  • 🎫Exit-ticket slips
Vocabulary

Key terms — hover for a quick definition

genea segment of DNA that codes for a traitalleleone version of a genetraita feature like eye colordominantthe allele that shows if presentrecessivethe allele that only shows when doubledgenotypethe allele combination (BB, Bb, bb)phenotypethe trait you can seePunnett squarea chart predicting offspring
Evaluate

Exit Ticket

Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.

QUESTION 1
Two Bb parents have a child. What is the chance the child has the recessive (bb) trait?
1 in 4 (25%).
QUESTION 2
What is the difference between genotype and phenotype?
Genotype is the allele combination (like Bb); phenotype is the visible trait (like brown eyes).
QUESTION 3
Why can a recessive trait skip a generation?
Because it can be hidden in a Bb carrier and only appears when a child inherits two recessive alleles (bb).

Going deeper? A dihybrid cross.

Have students set up a Punnett square for two traits at once and predict the offspring ratios. A printable Punnett-square sheet is in the Science library.

Study · Flashcards

Study the key terms

Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.

🃏 Genetics & HeredityFlip
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Practice · Quiz

Check your understanding

A quick self-check with instant feedback, drawn from this lesson’s key terms.

📝 Genetics & HeredityQuiz
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Practice · Worksheet

Printable worksheet

A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.

🖨️ Genetics & HeredityPrint
Name: ________________________
Date: ____________

Part A · Write the word that matches each meaning

Word bank: allele, dominant, gene, genotype, phenotype, Punnett square, recessive, trait
  1. a feature like eye color
  2. the trait you can see
  3. a chart predicting offspring
  4. the allele that shows if present
  5. the allele that only shows when doubled
  6. a segment of DNA that codes for a trait
  7. one version of a gene
  8. the allele combination (BB, Bb, bb)

Part B · Show what you learned

  1. Two Bb parents have a child. What is the chance the child has the recessive (bb) trait?
  2. What is the difference between genotype and phenotype?
  3. Why can a recessive trait skip a generation?
Answer key — Part A: 1) trait · 2) phenotype · 3) Punnett square · 4) dominant · 5) recessive · 6) gene · 7) allele · 8) genotype
Part B: 1) 1 in 4 (25%). 2) Genotype is the allele combination (like Bb); phenotype is the visible trait (like brown eyes). 3) Because it can be hidden in a Bb carrier and only appears when a child inherits two recessive alleles (bb).