Gold Seal Lesson:
Inheriting A Single Trait

Copernicus Education Gateway

Subject:

Science

Grade:

9-12

ICLE Standards:

Mathematics: Use and value the connections between mathematics and other disciplines. Understand and apply ratios, proportions, and percents in a wide variety of situations. 

Science: Develop an understanding of the molecular basic of heredity.

Performance Task:

Ted has blue eyes and each of his parents has brown eyes. From studying genetic traits in his biology class, Ted understands that the genes that express blue eyes are recessive. Therefore, Ted reasoned that each of his parents contributed a recessive gene for blue that caused him to have blue eyes. He could not help but wonder what the chances were that his parents could have produced a child with brown eyes and what were the chances for his eyes being blue. In this task you will work with a partner to simulate the phenotype and genotype of offspring of Ted's parents.

Materials Needed: 

• two coins or chips the size of a quarter or larger

• tape, pen, and paper

1. With your partner, label each side of a coin to represent the genes for eye color. One coin will represent Ted's father's genes and the other coin Ted's mother's genes. Since both of Ted's parents have brown eyes and Ted has blue eyes, the genotype for each parent is Bb, where B (brown) represents the dominant trait and b (blue) represents the recessive trait. Label one side of each coin with a B and the opposite side with a b.

2. Toss each coin 50 times. One student in the pair should toss the coin representing Ted's mother and the other student should toss the coin representing Ted's father. Record the genetic make-up of each toss, identifying the genotype and phenotype for each "offspring."

3. Find the total number of "offspring" who have the following genotypes: BB, Bb, and bb.

4. State the number of "offspring" who have blue eyes and the number who have brown eyes.

5. In your science lab book, write a brief summary of this simulation or experimental probability experiment, including the genotypic and phenotypic ratios.

6. State the experimental probability of Ted having blue eyes and the probability of his having brown eyes.
   

7. Find the theoretical probability of the genotypes and phenotypes by constructing a Punnet square representing the genetic make-up of Ted's parents.

8. Compute the percent of "offspring" for each genotype and each phenotype in the Punnet square.

9. Compare the results of your Punnet square cross with the coin tossing simulation. Make a written explanation in your lab notebook, including any inferences and/or conclusions that you can formulate.

Note to the teacher: At the completion of this activity students should have a greater understanding of how single traits are inherited and how to apply ratios and percentages.

Knowledge / Skills:

Know and apply the principles of scientific inquiry.  (xs1)

Examine the foundations of genetics involving heredity and inherited traits passed on through generations, understand the gene-chromosome concept, and apply classical genetic studies (Mendelian genetics).  (s12)

Perform operations with signed (positive and negative) numbers, including decimals, ratios, percents, and fractions.  (m1)

Understand the best procedures for statistical data collection, organization, and display.  (m5)

Understand the characteristic differences between theoretical and empirical probability (e.g., the theoretic probability of rolling a six an a die is 1/6; empirical probability is derived from repeated experimentation or accumulated statistics).  (m20)

Determine the probability of single and compound events using the basic premise that the probability of an event is equal to the number of ways it can occur divided by the total number of outcomes.  (m25)

Use writing as a tool for learning in formats such as learning logs, laboratory reports, note-taking, and journals.  (ela40)             

Rubric:

3 Points  =  The students complete the entire task on their own. Data are neatly organized. Mathematical calculations required in the task are error free. The students demonstrate that they understand how the genetic make-up of offspring is a result of chance in predictable ratios. The students understand that probabilities can be computed both experimentally by simulations and theoretically.

2 Points  =  The students complete all of the task, but need some coaching. Data are fairly neatly organized. Mathematical calculations are shown, but some minor errors occur in the students' work. The students demonstrate an understanding of how the genetic make-up of offspring is a result of chance in predictable ratios. The students need some help in understanding that probabilities can be computed both experimentally by simulations and theoretically.

1 Point  =  The students were not able to complete all of the activity even with considerable coaching. Data are not very well organized, resulting in some major errors. Their mathematical calculations contain several errors. The students demonstrate very little understanding of the genetics concepts addressed in this task. They do not understand simulations and do not see much relationship between theoretical and experimental probability.

0 Points  =  The students do not complete the activity and show no understanding of the mathematics or biological principles involved in the task. Little effort is put forth to do the task or understand the mathematics and biological concepts inherent in the task.

Keywords:

LIFE SCIENCE
GENETICS
SCIENTIFIC INQUIRY
HEREDITY
LAB EXPERIMENT

Grades:

Kg [] - 1 [] - 2 [] - 3 [] - 4 [] - 5 [] - 6 [] - 7 [] - 8 [] - 9 [X] - 10 [X] - 11 [X] - 12 [X]

ICLE Application:

D

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