Name: Period: Date: Student#: Day 1 - Take a Class Survey In this lab, you ll explore how greatly traits can vary in a group of people your

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1 Day 1 - Take a Class Survey In this lab, you ll explore how greatly traits can vary in a group of people your classmates. Question/Problem Are traits controlled by dominant alleles more common than traits controlled by recessive alleles? Materials - mirror (optional) - PTC paper Procedure Part 1 Dominant and Recessive Alleles 1. Write a hypothesis reflecting your ideas about the problem question (see answer sheet). 2. For traits 1, 2, 3, 4, and 5, work with a partner to determine which trait you have. Circle that trait in the data table below. 3. For trait 6, Taste the PTC paper your teacher gives you (do not eat the paper). Circle either can taste PTC or cannot taste PTC in your data table. CAUTION: Never taste any substance in the lab unless directed to by your teacher. 4. Count the number of students who have each trait. Record that number in the data table. Also record the total number of students. Part 2 Are Your Traits Unique? 5. Look at the circle of traits provided by the teacher. All the traits in your data table appear in the circle. Place the eraser end of your pencil on the trait in the small central circle that applies to you either free ear lobes or attached ear lobes. 6. Look at the two traits touching the space your eraser is on. Move your eraser onto the next description that applies to you. Continue using your eraser to trace your traits until you reach a number on the outside rim of the circle. Share that number with your classmates. P T E R 3 S K I L L S L A B

2 1. Are traits controlled by dominant alleles more common than traits controlled by recessive alleles? Hypothesis: 2. Data Table Circle your Traits, record the total number of student in the class, number of students with each trait and calculate the percentages of each in the class Total Students in Class: Bead/ Trait Trait A - opaque Symbol # % Trait B - transparent Symbo l # % Bead Color 1 Free ear lobes E Attached ear e Blue lobes 2 Hair on fingers F No hair on f Green fingers 3 Widow s peak W No widow s w Red peak 4 Curly hair H Straight hair h orange 5 Smooth chin C Cleft chin c yellow 6 Can taste PTC* P Cannot taste PTC* p white * PTC stands for phenylthiocarbamide. Analyze and Conclude Create a graph to compare the column A and B student numbers for each trait. Use the information on the table and graph to answer the following questions: 1. The traits listed under Trait A in the data table are controlled by dominant alleles. The traits listed under Trait B are controlled by recessive alleles. Which traits controlled by dominant alleles were shown by a majority of students? Which traits controlled by recessive alleles were shown by a majority of students? 2. How many students ended up on the same number on the circle of traits? How many students were the only ones to have their number? What do the results suggest about each person s combination of traits? 3. Think About It. Do your data support the hypothesis you proposed in Step 1? Explain your answer with examples.

3 Day 2 Graphing Data and Creating Phenotype Bracelets 1. Use the Data table generated in the day 1 s activities to generate a graph of the data below. Chose a graph that best depicts the data. Make sure you correctly label data and axis.

4 2. What are three observations that you can make by reviewing the graph that you generated from the class statistics? 3. Your Phenotypes/Genotypes in the table below, rerecord your phenotypes and generate a list of your possible genotypes. Phenotypes/Genotypes Trait/Bead # Trait Phenotypes Dom/Rec Possible Genotype(s) 1 - blue Earlobes 2 - green Hair on Mid Digit 3 - red Widow s Peak 4 - orange Curley Hair 5 yellow Smooth Chin 6 - white PTC Taster 4. Based on the Phenotypes, assemble a bead bracelet with pony beads using opaque beads for dominant traits and clear beads for the recessive traits. Assemble the beads in the string provided in the color order above. Tie off the bracelet so that the beads do not fall off. In order to pass the assignment, the beads must be returned after every phase of this assignment. No beads no grade. Today you will assemble a bracelet and the beads MUST be returned tomorrow to assemble another bracelet. 5. You will be comparing your bead bracelet with that of your fellow students today. What are three observations, which you expect to see? 6. Homework. Because you have two possible genotypes for you dominant traits, you will need to observe your biological parents phenotypes in order to best predict your genotypes. If either parent has the recessive phenotype, select the heterozygous form of the dominant genotype. If both parents have the dominant genotype, select the homozygous form. If you cannot determine you parents phenotypes, flip a coin to determine you zygosity. You will need to have the best prediction of your genotype for the next activity.

5 Day 3 Phenotype Observations and Genotype Bracelets 1. Based on your observations of the actual bracelets worn by the other students, write 3-5 sentences discussing what saw verses what you predicted. In other words, how were things similar or different from what you thought? 2. Briefly describe how you best predicted you genotype in last nights homework: 3. Copy your phenotypes and predicted genotyped form the Day 2 worksheet. Trait/Bead # Trait Phenotypes Predicted genotype 1 - blue Earlobes 2 - green Hair on Mid Digit 3 - red Widow s Peak 4 - orange Curley Hair 5 yellow Smooth Chin 6 - white PTC Taster 4. Today you will assemble genotype bracelets based on your best prediction. If you do not have the beads from yesterday you will not be able to participate in today s activities. As with yesterday s bead activity, if you do not return the beads tomorrow you will not receive a grade. List three observations you might expect to see when you look at the other students bracelets.

6 Day 4 Review Genotype Observations and Complete Worksheets 1. Discuss at least three observations that you made based on the genotype bracelets that were different or similar from the observations made of phenotypes: 2. How does the graph of your class s phenotypes compare to that of the rest of the classes and other 7 th graders? 3. List at least one thing you learned form this activity: 4. What part of this activity, if any, have you feel confusion about?

7 Day 5 Determining Offspring s Phenotype and Genotypes Probability Sex (XY) Earlobes blue (Ee) Hair on Digit green (Ff) Widow s Peak red (Ww) Curley Hair orange (Hh)

8 Chin yellow (Cc) PTC white (Pp)