## Analysis of Student Work

The activity in the section on probability and heredity was a hook, so get students involved in determining probability and how it relates to heredity.  Students completed three activities:  the first looking at the probability of getting heads or tails by flipping a coin; the second a quick math tutorial on calculating percentages for probability; the third using coin tosses to determine alleles passed to offspring from parents.  Students were asked to complete the activities as directed in the book, as a lesson on following instructions.  They were also asked to design two data tables to represent their results, and answer all questions using complete sentences.

Before beginning the activity, I spoke with one of our math teachers about when the students would cover probability.  They were going to do so later in the year, but had done a little bit the year prior.  After beginning the activity, it turns out that most of the students had a strong understanding of probability, and probably did not need to complete the first two activities, so I spent most of my time looking at the results of the second activities.  A few things I noticed:
• students struggle with what a compete sentence is
• students can write down their results, and Mendel's results, but don't know how to compare the two
• students struggle with constructing a data table

Attached is the completed analysis of student work, breaking down the individuals who meet, exceed, or are below objectives, along with strategies for gathering more information, or correcting misunderstandings.  Along with that are some examples of the student lab write-ups.  In the student examples, the first two are below, the next two meet, and the final two exceed the objectives.
 analysis_of_student_work.pdf File Size: 223 kb File Type: pdf

 student_examples.pdf File Size: 2550 kb File Type: pdf

## Unit Test Results

At the end of the two sections, Mendel's Work and Probability and Heredity, the students were given a unit exam. This test was a combination of multiple choice, fill-in, and short answer/essay questions.  When grading the tests, most of the students did well and passed the test, with only a small percentage not passing.  To look for student understanding, I spent most of my time looking at the essay questions at the end of the test.  Each essay was worth 3 points, 2 for various answers, and 1 for using complete sentences as instructed.

One of the questions asked the students to draw a Punnett Square and predict the probability of a particular phenotype.  Most of the students in all of my classes were able to draw both the Punnett Square and make the prediction.  For those unable to draw the Punnett Square, they copied down the genotypes incorrectly, or possibly didn't understand the question.  For the probability, it seemed that those who got it wrong struggle with assigning the correct phenotype to a genotype.

Another question asked students to explain why a plant with yellow pods can never be a hybrid, after explaining that green is controlled by a dominant allele.  I was looking for students to explain that a hybrid has one dominant and one recessive allele, so would always be green, or that the yellow plant would have to have two of the recessive alleles to be yellow.  Students who got this one wrong showed a lack of understanding about what the word hybrid meant, or that the plant had to have two recessive alleles.

The third question asked students to explain why Mendel's cross of purebred tall and short pea pants resulted in only tall plants.  I was looking for students to explain that the offspring got one allele from each parent, so would have both a dominant and recessive allele (heterozygous), so would all be tall since that was dominant.  For student who go this one wrong, it was mostly due to incomplete answers.  They would explain that the offspring were Tt, but didn't explain anything about tall being dominant.  Or they would explain that tall was the dominant allele, but did not say anything about the offspring being heterozygous.  Both of those answers earned the students partial credit.

Following are some selected tests showing student examples of answers to these questions.  These tests were volunteered by the students for examples, and are all examples of students who were not able to master the essay questions.
 student_examples.pdf File Size: 3798 kb File Type: pdf