ScienceMakers Toolkit Manual - The History Makers

10. Dr. Bowman joined the faculty of the University of Chicago. What was unusual about this process? He
also mentions that the kind of work he wasn’t expecting to do in Iran led him to his job at U of C.; some
might say that he was lucky. Coach Darrel Royal said, “Luck is what happens when preparation meets
opportunity.” How does this quote apply to Dr. Bowman? How can you apply it to your own life?
(Clip #5)
11. Dr. Bowman works with diseases. He states that cancer will eventually be eliminated. What is his
thought process behind this? What are some of the other diseases that have been wiped out in the last
century? Do you think it is possible to cure cancer? How would you go about curing cancer? (Clip #6)
12. Dr. Bowman also works in the fi eld of genetics. What does genetics mean? Where have you heard of
genetics before? How does the study of genetics impact your life?
Experiment - Genetics: The Easy Way Developed by Yash Shah
Information for the Teacher
For several years I struggled, as a student, then as a teacher, with genetic problem solving, using the Punnett
Square or the Product Rule method, and following the textbook closely. Few students succeeded in the di- or trihybrid
problem solving. Then, one year on the chalkboard, in the process of explaining it to my students, I saw
straight through it. Realizing that all calculating probability is multiplication, that multiplying 3X5X4 provides
the same answer as multiplying 4X3X5, and that the Punnett Square is the same as the elementary school multiplication
table, I created an alternative method to solving genetic problems quickly and accurately.
To teach this lesson a variety of strategies are used, including team and solo problem solving, lecture and demonstration,
and hands-on lab exemplifi cation. First I create hypothetical critters with their own fun gene pool;
these have included either Marlings from Mars or a Recycle Critter. A Recycle Critter is created in a lab setting
by students making male and female heterozygous parents with 5-8 sets of chromosomes and performing
fertilization. They then build the phenotype of their Recycle Critter baby.
Next, students practice and master the six basic monohybrid problems in small groups and on the board explaining
them in front of their peers. I then demonstrate solving a dihybrid problem by simply multiplying the
answers of two monohybrid problems together. The preferred method is what I call the forked-line method; I
prefer it since it will line up the genotypic and phenotypic ratios in a nice order, saving the time of counting
through all the squares.
To do this method, one simply writes the ratio of the fi rst cross one on top of another with some space in between,
then draws n lines out from each one (n=equal to the number of possibilities in the ratio of the second
cross) and writes the ratio of the second cross by each possibility of the fi rst cross. Next, one simply multiples
along the forked-line to get the fi nal ratio; this can be done with genotypic ratios, which can be converted to
phenotypic ratios, or can be done with just phenotypic ratios. To double-check the problem, make sure the sum
of the ratio is equal to 4n. Furthermore, if the problem just asks for the possibility of one particular phenotype,
then all one would have to multiply together are the predicted probabilities for that phenotypic combination.
Another method is to multiply the answers of the two squares together by creating a third Punnett Square;
however, this time instead of gametes on the sides, the ratio of one monohybrid cross goes on one side and the
ratio of the other cross goes on the other side. As I have explained in the fi rst paragraph, I usually also tell my
students how I derived these methods; this lets them see how the math they have already learned can be applied.
Because the 16-square Punnett Square is in the text, and especially because my methods do not allow for one to
fi nd gamete possibilities, I also teach the textbook method. Students receive a “How-To” step-by-step handout
on all methods and are given the opportunity to practice several problems.
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Life Science