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Name _____________________ Date ___________ Periods ______ Lab Partners ___________________ Rabbit Gene Pool Natural Selection Activity Objective: Model natural selection in a population of rabbits while reviewing concepts of genotype and phenotype Background: Review of genetics terms from 7th Grade Science: Genotype = the genetic information inheritied from parents expressed in a pair of letters such as BB, Bb, bb Phenotype = the outward expression of a genotype, such as brown, gray or white fur on a rabbit Homozygous = a purebred genotype with two of the same genes such as BB or bb Heterozygous = a hybrid genotype with two different genes such as Bb Scientific Question: What is the result of natural selection? Materials: brown and white beans, paper bag, plastic cup, pencil and worksheet packet Procedure Part A: First Generation (No Natural Selection) 1. Write “Rabbit Gene Pool” on a paper bag. Choose who will be the Chooser, Bean Counter, Recorder for the group. 2. Place 10 brown beans and 10 white beans into the bag. This represents the offspring of two gray (heterozygous, Bb for fur color) rabbits. 3. Without looking into the bag, take out two beans to represent an offspring (each baby has two genes, one from each parent). DO NOT return the beans to the bag. Write the two letter genotype (BB, Bb or bb) of the beans on the chart below. Write the phenotype (brown, gray or white) for fur color in the next column. 4. Continue taking the beans out of the bag two at a time until all beans are removed. Tally the number of each type of rabbit in the table at the bottom of the chart. First Generation Rabbit Offspring (no natural selection) Rabbit # Genotype of fur color gene (BB, Bb, or bb) Phenotype fur color gene (brown, gray or white) 1 2 3 4 5 6 7 8 9 10 Genotype Key Brown bean = B = gene for brown fur White Bean = b = gene for white fur Phenotype Key BB = brown fur Bb = gray fur bb = white fur Tally of Rabbits with Each Fur Color Number of Offspring with each Fur Color First Generation (no natural selection) Second Generation (after natural selection) Brown (BB) Gray (Bb) White (bb) Name _____________________ Date ___________ Periods ______ Lab Partners ___________________ Procedure Part B: Second Generation (After Natural Selection) 1. To model natural selection, this will be a forest environment, like the woods behind the field here at CMS. You should assume that predators eat all of the white rabbits, and one half of the gray rabbits. 2. To show this, lightly cross out all of the white rabbits and half of the gray rabbits from the First Generation Rabbit Offspring chart from Part A on the other side, AND remove the beans representing these “rabbits” from the from the current gene pool . Put the beans from these no longer living “rabbits” into the predator cup. 3. Now we will assume that each surviving rabbit from the First Generation has a litter of six babies. To show this, for each First Generation brown rabbit, count out 12 new brown beans for the Second Generation (12 beans representing the genes for six baby brown rabbits). Place these 12 beans plus the two beans for the “mom” brown rabbit and into the Rabbit Gene Pool bag. This means a total of 14 brown beans in the gene pool for each brown rabbit from the First Generation. 4. For each surviving gray rabbit from the First Generation, put 6 brown beans and 6 white beans (one of each color gene representing the genes of the gray “mom” rabbit) into the Rabbit Gene Pool bag. Also place one brown and one white bean into the bag representing the gray “mom” rabbit. 5. Repeat steps 3 and 4 from Part A (other side!) and use the chart to record the second generation of rabbit offspring. You may not need all 35 lines, depending upon your First Generation offspring. 6. Tally your results and add to the Tally Table on the bottom front side of this sheet. 7. Answer analysis questions on the next page using complete sentences and scientific thinking. 8. We will create a bar chart for the first and second generation of rabbit offspring showing the three phenotypes using Excel. This will become part of your completed project, along with this completed packet. Second Generation Rabbit Offspring (Part B) Rabbit # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Genotype of fur color gene (BB, Bb, or bb) Phenotype fur color gene (brown, gray or white) Name _____________________ Date ___________ Periods ______ Lab Partners ___________________ Analysis (to be done after completing Second Generation Chart) The Basics 1. What does each bean represent? ____________________________________________ ________________________________________________________________________ 2. What does a pair of beans represent? _________________________________________ ________________________________________________________________________ 3. What do all the beans in the bag represent? ____________________________________ ________________________________________________________________________ Observe the Data 4. How did the rabbit gene pool change from the First Generation to the Second Generation? _____________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 5. What happened to the percentage of white rabbits after natural selection occurred? ________________________________________________________________________ ________________________________________________________________________ 6. What happened to the percentage of brown rabbits after natural selection occurred? ________________________________________________________________________ ________________________________________________________________________ Think About It 7. If this type of natural selection continues, will the white rabbit gene ever completely die out? _____ Explain your answer _____________________________________________ ________________________________________________________________________ ________________________________________________________________________ 8. How is this model similar to the way natural selection occurs in nature? _____________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 9. How is this model UNLIKE the way natural selection occurs in nature? _______________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Name _____________________ Date ___________ Periods ______ Lab Partners ___________________ 10. Challenge: Think about how the environment may change, and how those changes could affect natural selection in this population of rabbits. Explain your answer here. ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________