Genetic Variation Lesson 2: The Make Student Handout Before You Begin: Have you ever noticed the features of children of the same parents and think, I wonder why some siblings don t look alike? Today you ll get to see why some organisms show variation and why others do not. You re going to make models to explore sexual and asexual reproduction by creating two alien families to help us understand the process and outcomes of genetic variation. Your Make task today is to: 1. Create two alien families: one that produces babies sexually and one that produces babies asexually. 2. Model how genes are passed from parents to offspring 3. Make and display your alien babies in a presentation that includes A title with the family tree of each of your alien babies A description of their reproductive process (asexual or sexual) Directions: In the Make activity, we will represent gene alleles using capital and lowercase letters. What are gene alleles? Gene alleles are forms of the gene on a chromosome. For example, on a chromosome, you will have genes that control eye color and hair color. One of these genes comes from the father and one comes from the mother. Gene alleles will either be dominant or recessive. A dominant trait will mask or hide a weaker trait, called a recessive trait. Dominant alleles will be represented by capital letters, and recessive alleles with lowercase. Look at the the Allele Codebreaker below to see examples of how dominant alleles and recessive alleles combine to make alien traits. 1
Allele Codebreaker H= Circular head (dominant trait) h = Square head (recessive trait) T = Tongue out (dominant trait) t = Teeth (recessive trait) E = One eye (dominant trait) e = Four eyes (recessive trait) Combinations and Traits: Gene Dominant Trait (At Least One Capital Letter) Recessive Trait (Both Lowercase Letters) Head Shape (H) Circular (HH or Hh) Square (hh) Mouth Features (T) Tongue Out (TT or Tt) Teeth (tt) Number of Eyes (E) One Eye (EE or Ee) Four Eyes (ee) Check your knowledge: So far we know that genes are on chromosomes and they code for different features. We also know that genes can either be dominant or recessive. Before doing the activity, quiz yourself. Using the allele codebreaker above: 1. What feature will an alien baby have if it gets a dominant allele H from the father and a dominant allele H from the mother? 2. What feature will an alien baby have if it gets a recessive allele t from the father and a recessive allele t from the mother? Did you do well on those first two questions? See how you do on these last two! 3. What feature will an alien baby have if it gets a dominant allele E from the father and a recessive allele e from the mother? 4. What feature will an alien baby have if it gets a dominant allele T from the father and a recessive allele t from the mother? Answers: 1. H from the father + H from the mother = HH. Using the allele codebreaker, we see that HH codes for a circular head. 2. t from the father + t from the mother = tt. Using the allele codebreaker, we see that tt codes for teeth. 3. E from the father + e from the mother = Ee. Using the allele codebreaker, we see that Ee codes for one eye. 4. T from the father + t from the mother = Tt. Using the allele codebreaker, we see that Tt codes for tongue out. Great work! Now let s get to your tasks for today! 2
Task 1 - Sexual Reproduction 1. Your teacher will give you your Parent Allele Card (YOU are the Parent Alien!). Use the Allele Codebreaker to figure out what traits you have. a. Record your parent traits in your Planning Organizer - Sexual Reproduction: Step 1. (See diagram on page 3) b. Raise your hand to have your planning organizer checked and confirmed before moving on. c. Find a partner. This will be the other parent with whom you will create an alien baby! 2. Get 4 pipe cleaners of one color (2 short and 2 long) that you will use to represent your parent alleles. Each partner must have a different color set of 4 pipe cleaners: Remember: long pipe cleaner = Dominant allele (CAPITAL LETTERS) and short pipe cleaner = Recessive allele (lowercase letters) allele pipe cleaners colors are different for each parent a. With your partner, fill out the first part of your planning organizer about you and your alien mate. b. Record your partner traits in your Planning Organizer - Sexual Reproduction: Step 2. (See diagram on page 3) 3. Now you will start the reproductive process with your partner to create your alien baby. (Diagram on Page 3) These steps will be repeated for each GENE: a. Gene = Head Shape: i. Each parent identifies the two pipe cleaners that represent the alleles for their own head shape trait. ii. Each parent puts into the paper bag the two pipe cleaners that represent the alleles for their head shape. iii. To randomly determine your baby s traits, each parent will pull ONE pipe cleaner from the paper bag. After one parent pulls the first pipe cleaner from the bag, the other parent must pull one pipe cleaner of a different color. It may take several tries! iv. Both parents record the baby alien trait for HEAD SHAPE in your Planning Organizer - Sexual Reproduction: Step 3. (See diagram on page 3) b. Repeat steps i - iv for MOUTH FEATURES and NUMBER of EYES, re-using your pipe cleaners and recording the results in your planning organizer each time. 4. Next, draw out each feature of your alien baby below in Step 4 of your planning organizer 5. Finally, draw your alien baby in Step 5 of your planning organizer 3
Example of Step 1 and 2 : Record your traits as a parent alien and your partner s traits as a parent alien. Draw them in your planning organizer. Round Head Tongue Out 1 Eye Square Head Teeth 4 Eyes Hh Tt Ee hh tt ee Example of Step 3 : Put 2 pipe cleaners for your head shape alleles (one color) and 2 pipe cleaners for your partner s head shape alleles (a different color) into the paper bag. Pick out one of each color for your baby s head shape! Be sure to use the allele code breaker to figure out the trait! For example: 4
Your Task 1 Planning Organizer: Sexual Reproduction Step 1: What does your alien parent look like? What are the alleles (letters) for the traits? Describe the characteristics here: Head shape: Mouth features: Number of eyes: Alleles: Alleles: Alleles: Draw a sketch of your alien parent (YOU!) Step 2: What does your alien mate look like? What are the alleles (letters) for the traits? Describe the characteristics here: Head shape: Mouth features: Number of eyes: Alleles: Alleles: Alleles: Draw a sketch of your alien mate 5
Step 3: Record the characteristics and alleles (letters) of the traits for your alien baby: My Baby Alien Genes *Include the alleles in parentheses Head Shape Mouth Features Number of Eyes Exact same features as you? (yes or no - explain) Exact same features as mate? (yes or no - explain) Baby Step 4: Draw out each feature of your alien baby below: Head Shape Mouth Features Number of Eyes Step 5: Draw a sketch of your alien baby putting together all of its features here: 6
Task 2 - Asexual Reproduction Great job! Now you re going to use your same Parent Allele Card and the Allele Codebreaker for this task about asexual reproduction. 1. Record what your alien parent looks like in your Planning Organizer - Asexual Reproduction : Part 1. *Note: This will be identical to the first part of your planning organizer for Sexual Reproduction. 2. Now you will start the reproductive process to create your alien baby. Hint : asexual reproduction involves only making a copy of one parent like we saw with the Volvox colony in the video. These steps will be repeated for each GENE: a. Gene = Head Shape: i. You, as the one parent, identifies the two pipe cleaners that represent the alleles for your own head shape trait. ii. Puts into the paper bag the two pipe cleaners that represent the alleles for your head shape. iii. Pull ONE pipe cleaner from the paper bag for each allele (2 alleles iv. total). This time your pipe cleaners can be the same color! Record the baby alien trait for HEAD SHAPE in your Planning Organizer- Asexual Reproduction. b. Repeat steps i - iv for MOUTH FEATURES and NUMBER of EYES, re-using your pipe cleaners and recording the results in your planning organizer each time. 3. Complete the part of the planning organizer that asks you to predict the characteristics of the offspring produced by asexual reproduction. 7
Task 2 - Planning Organizer - Asexual Reproduction Part 1: What does your alien parent look like? What are the alleles (letters) for the traits? Describe the characteristics here: Head shape: Mouth features: Number of eyes: Alleles: Alleles: Alleles: Draw a sketch of the alien parent Predict and record the characteristics and alleles (letters) of the traits for your alien baby produced by sexual reproduction: My Baby Alien Genes *Include the alleles in parentheses Head Shape Mouth Features Number of Eyes Exact same features as you? (yes or no - explain) Exact same features as mate? (yes or no - explain) Baby 8
Predict and record the characteristics and alleles (letters) of the traits for your alien baby produced by asexual reproduction: My Baby Alien Genes *Include the alleles in parentheses Head Shape Mouth Features Number of Eyes Exact same features as you? (yes or no - explain) Baby Draw the Alien Baby that was produced by asexual reproduction: 9
Task 3 Make Your Presentation: Alien Baby Genetic Family Trees (Sexual and Asexual Reproduction) Your alien babies want to know where they came from! On a separate piece of printer or poster paper, you will draw visual Family Trees with diagrams and arrows to show from which parent your alien baby got its traits. Use the Science & Engineering Practices Rubric to guide your work. The rubric describes levels of quality that will be used to assess your presentation As you create each family tree, check off each requirement in the checklist. Suggested family tree organization plans are provided below. Your alien portraits can be draw in the frames. Start with the Sexual Reproduction Family Tree and its checklist Finish with the Asexual Reproduction Family Tree and its checklist Create titles, headings and use color to enhance your presentation When you have completed your presentation, do the Exit Ticket Science & Engineering Practices Rubric Emerging (1) Developing (2) Proficient (3) Advanced (4) Developing and Using Models Drawings, diagrams, or visual models include major misconceptions or has missing parts. Explanation of the model is minimal or not present. Drawings, diagrams, or visual models include minor misconceptions or has missing parts. Explanation of the model is minimal. Drawings, diagrams, or visual models are complete, but contain a minor misconception. Explanation of the model is complete but lacking complexity. Drawings, diagrams, or visual models have no misconceptions and contain all details. Explanation of the model is complete and complex. Constructing Explanations or Arguments From Evidence Constructs an explanation with no clear sources of evidence. Uses scientific principles and/or data from at least one source to construct or evaluate an explanation, but explanation contains minor misconceptions. Uses accurate but incomplete scientific principles and/or data from multiple sources to construct or evaluate an explanation. Uses accurate and complete scientific principles and/or data from multiple sources to construct or evaluate an explanation. 10
The Make: Family Tree Organization for Sexual Reproduction Genetic Variation Sexual Reproduction Make Checklist: Content Concepts and Practices A drawing of your alien parent with its 3 traits. Label the traits Show the alien alleles for each of the 3 traits A drawing of your mate with its 3 traits: Labels the traits Show your mate s alien alleles for each of the 3 traits A drawing of your alien baby with its 3 traits: Labels the traits Show your alien baby s alleles for each of the 3 traits Uses arrows to clearly show where the alien baby s genes come from Origin of each allele: Which allele for each trait is passed from mother to baby? Father to baby? Result of the combination of the alleles from parents for a particular trait in baby: Has a clear, but brief caption under baby alien s combined allele for each trait explaining: Whether sexual reproduction did or did not create genetic variation in the baby (Does the baby have different genes than parents? Why or why not?) Has a clear and creative title Family Tree shows relationships in a logical order Family Tree is neat and in color 11
The Make: Family Tree Organization for Asexual Reproduction Genetic Variation Sexual Reproduction Make Checklist: Content Concepts and Practices A drawing of your alien parent with its 3 traits: Label the traits Show the alien alleles for each of the 3 traits A drawing of the alien baby with its 3 traits: Labels the traits Show your baby alien alleles for each of the 3 traits Uses arrows to clearly show where the alien baby s genes come from Origin of each allele: Which allele for each trait is passed from parent to baby? Whether asexual reproduction did or did not create genetic variation in the baby (Does the baby have different genes than parent? Why or why not?) Has a clear and creative title Family Tree shows relationships in a logical order Family Tree is neat and in color 12
Exit Ticket: Connection to the Design 1. How do alleles relate to the trait that you can see? 2. Does sexual reproduction result in a mix of traits being passed on to the offspring? Explain. 3. Does asexual reproduction result in a mix of traits being passed on to the offspring? Explain. 4. In sexual reproduction, is it possible to make a baby alien that is a genetically exact copy of the parents? Explain. 5. In your own words, what is genetic variation and how is it achieved? 13