Week 22

Monday, February 10, 2020 (HS-LS3-3): We kicked off the short week with an entry task designed to reinforce the concept of independent assortment and introduce the idea of dihybrid crosses (two trait Punnett Squares).  Students each received two coins: a penny and a nickel.  Each coin represented a different chromosome.  Heads represented the dominant allele of a gene (P or N) and tails represented the recessive allele (p or n).  Students were tasked with identifying the 4 possible allele combinations of the two genes (PN, Pn, pN, and pn).  Next, we constructed a dihybrid cross to determine the 16 possible allele combinations between two heterozygous parents (PpNn x PpNn).  Class notes are shown below:

200210 Biology Pic 1

200210 Biology Pic 2

Students had the remainder of class to complete the One-Trait Gizmo from last week and then to work through the Two-Trait Punnett Square Gizmo which included an additional review and application of the vocabulary learned thus far.


Tuesday, February 11. 2020 (HS-LS3-3): Class began with the following entry task:

Set up, filled in, and analyze the three one-trait Punnett Squares below, then complete a dihybrid cross for two parents with genotypes AaBb and AaBb.

Finally, students had the remainder of the class period to work through all unfinished work.  Students will be quizzed on one and two-trait Punnett Squares on Thursday.

Keep Learning!

Review dihybrid crosses by watching the video by Mr. Anderson of Bozeman Science:


Wednesday, February 12, 2020 (HS-LS3-3): Today is the final work day this week.  All work from this unit is due today for full credit.  Students should carefully study their notes for the quiz tomorrow.  Students who have additional time are challenged to construct, solve, and analyze a tri-hybrid cross for three independently assorting genes (penny, nickel, and quarter) where both parents are heterozygous.

Entry Task:

Student Examples of Trihybrid Crosses (Wow!):

Trihybrid Cross Example 1

Trihybrid Cross Example 2

Trihybrid Cross Example 3


Thursday, February 13, 2020 (HS-LS3-3): Punnett Square quiz


Friday, February 14, 2020: No School (Mid-Winter Break)

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