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BIO WEEK 7 EXPERIMENT ASSIGNMENT-Experiment 7 Exercise 1: Evolutionary Change without Natural Selection

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Question;WEEK 7 EXPERIMENT ANSWER SHEETPlease submit to the Week 7 Experiment dropbox no later than Sunday midnight.SUMMARY OF ACTIVITIES FOR WEEK 7 EXPERIMENT ASSIGNMENTExperiment 7 Exercise 1 Evolutionary Change without Natural SelectionExperiment 7 Exercise 2 Evolutionary Change with Natural SelectionExperiment 7 Exercise 3 Evolution and Genetic DriftBefore starting, be sure you have read over the information in the Week 7 ExperimentIntroduction.Materials NeededFor the first two exercises you will need the following:50 red M&Ms and 50 green M&Ms or 50 each of two items that are distinguishable bycolor but are similar in size and texture (e.g., dimes and pennies, two different colorbeads).Four containers large enough to hold the above items.Experiment 7 Exercise 1: Evolutionary Change without Natural SelectionIn this first exercise, we are going to look for evidence of evolutionary change in a population inthe absence of natural selection by looking at the change in allele frequencies over time in asimulated population. We will start with a population of 50 individuals in which there are twoalternate alleles (H and h) in equal proportions (each at a frequency of 0.5 or 50%). Individualshave the possible genotypes: HH, Hh or hh. These two alleles do not offer any selectiveadvantage, so neither is selected for or against, meaning they are neutral. We will record thefrequency of these alleles over 10 generations. Prior to advancing on to the next generation,six alleles (= three individuals) will be removed at random.Before you begin, answer the following:Question1. What is your prediction as to what will happen to the frequencies (note that this isdifferent than the number) of these two alleles over 10 generations? Word yourprediction as an if-then statement based on the experiment design. (1 pts).Updated October 2013Procedure:A. Let 50 M&M's of one color (i.e. red) represent the dominant allele (H) and 50 M&M's ofanother color (i.e. green) represent the recessive allele (h).B. Let one container represent the Habitat where random mating occurs. Place all of theM&Ms (or other items) into this container. This is your starting gene pool of yourparent population or Generation 0.C. Label the other three containers HH for homozygous dominant individuals, Hh forheterozygous individuals and hh for the homozygous recessive individuals. Notice thatindividuals have two alleles.D. Mix up your Habitat well and without looking, select two items (alleles) at a time, thesetwo alleles represent a single individual. On a piece of paper, keep track of thegenotypes of the individuals withdrawn. For instance, if you draw one red and onegreen M&M, that counts towards "Number of Hh individuals." If you draw two red M&Ms,that counts towards "Number of HH individuals" and so on.E. Continue drawing pairs and recording the results until all items (alleles) have beenwithdrawn and sorted. Be sure to place the offspring into the appropriate dish: HH, Hh,or hh. Note that the total number of individuals will be half the total number of itemsbecause each individual requires two alleles, so you will have 50 offspring (but 100alleles). Record the number of HH, Hh and hh individuals drawn for Generation 1 inTable 1 below.F. Next count (or calculate) the total number of H and the total number of h alleles for thefirst generation and record the number in Table 1 below in the columns labeled"Number of H Alleles" and "Number of h Alleles."G. Add up the total number of H alleles and h alleles for the first generation and record thisnumber in the column labeled "Total Number of Alleles." If you did everything correct,you should still have 50 H alleles and 50 h alleles. This has already been entered foryou in the Table below for Generation 1.H. Combine the HH, Hh and hh individuals back into the Habitat container and mix well.Randomly remove three pairs of alleles (= three individuals, six items) and set themaside.I. Repeat steps D through H to obtain Generations 2 through 10. Remember to randomlyremove three pairs of alleles each time. Because I know that each generation will havesix fewer alleles, I have also entered the total number of alleles in the Table below. Besure that is the number your alleles add up to!Here is a photograph of this process after six generations. The sixth generation has beendistributed into the HH, Hh and hh containers. Note that dimes and pennies have been used.Updated October 2013J. After entering your number of individuals and allele counts for each generation, you nowneed to determine the allele frequency of H and h for each generation and record themthe Table below. To determine allele frequency take:o # of H /Total alleles in the generation = Allele frequency of H (express as adecimal)o # of h /Total alleles in the generation = Allele frequency of hNote that the total number of alleles will change each generation, but the frequency the Hallele plus the frequency of the h allele should add up to 1.0 for each generation.Table 1. Results evolutionary change without natural selection (2 pts).GenerationNumberofHHindividuals1NumberofHhindividualsNumberofhhindividualsNumberofHallelesNumberofhallelesTotalNumberofallelesAlleleFrequencyofHAlleleFrequencyofh50501000.50.52943884825766707648589521046K. Generate a line graph of Allele frequency vs Generation. This means you need tograph the last two columns of your data in the Table above. Paste your graph below. Besure to label your axes (3 pts).Updated October 2013Questions2. Describe what your graph above depicts with respect to the frequency of the twodifferent alleles across generations (2 pts).3. Was your prediction correct? Why or why not (1 pts)?4. Define evolution. Are the results of this simulation an example of evolution? Explainyour answer. Cite any sources used (4 pts).Experiment 7 Exercise 2: Evolution Change with Natural SelectionIn this second exercise, we will determine the effect that natural selection has on thefrequency of two alleles which start off in equal proportions (50:50) in the population. This time,individuals who are hh die, meaning the homozygous recessive allele combination is lethal.These individuals will be removed from the gene pool when they are drawn and will notcontribute to the following generation. This means that the h allele is being selected against.Keep in mind that carriers of this lethal allele (e.g., those individuals that are Hh) areunaffected because the h allele is recessive.Question1. What is your prediction as to what will happen to the frequencies of these two allelesover 10 generations? Word your prediction as an if-then statement based on theexperimental design. (1 pts).Procedure:A.Return ALL alleles to the Habitat container and ensure that itcontains 50 H alleles and 50 h alleles. This is our Generation 0.B.Use the other three containers labeled HH for homozygousdominant individuals, Hh for heterozygous individuals and hh for the homozygousrecessive individuals.C.Mix up your Habitat container well and without looking, select twoalleles at a time, these two represent a single individual. On a piece of paper, keeptrack of the type of individual withdrawn (HH, Hh or hh).D.Continue drawing pairs and recording the results until all alleleshave been withdrawn and sorted. Be sure to place the offspring into the appropriatedish: HH, Hh, or hh. Record the number of HH, Hh and hh individuals drawn forGeneration 1 in Table 2 below.Updated October 2013E.Next count (or calculate) the total number of H and h alleles for thefirst generation and record the number in the Table below.F.Add up the number of H alleles and h alleles for the first generationand record this number in the column labeled "Total Number of Alleles." If you dideverything correct, you should still have 50 H alleles and 50 h alleles. This has alreadybeen entered for you in the Table below for Generation 1. You will need to enter thisinformation for Generations 2-10, as it will change.G.Now it is time for natural selection. Remove all of the h allelesfrom the container labeled hh and discard them. These individuals have died andcannot reproduce.H.Return the alleles of the remaining HH and Hh individuals back tothe Habitat container.I.Repeat steps D through H to obtain Generations 2 through 10.Remember that each time, all hh individuals die and are removed after you havecounted them.J.After entering your number of individuals and allele counts for eachgeneration, you now need to determine the allele frequency of H and h for eachgeneration and record them in Table 2 below.Table 2. Results from evolutionary change with natural selection (2 pts).GenerationNumberofHHindividuals1NumberofHhindividualsNumberofhhindividualsNumberofHallelesNumberofhallelesTotalNumberofallelesAlleleFrequencyofHAlleleFrequencyofh50501000.50.52345678910K.Generate a line graph of Allele frequency vs Generation #. Thismeans you need to graph the last two columns of your data in the Table above. Pasteyour graph below. Be sure to label your axes (3 pts).Updated October 2013Questions2. Describe what your graph above depicts with respect to the frequency of the two differentalleles across generations (2 pts).3. Was your prediction correct? Why or why not (1 pts)?4. Explain why the h allele was not entirely eliminated from the population (2 pts).5. Based on your earlier definition of evolution, are the results of this simulation anexample of evolution? Explain your answer (2 pts).Experiment 7 Exercise 3: Mechanisms of Evolutionary ChangeBe sure that you have completed the suggested readings, your success on this exercise isdependent on your understanding of evolutionary concepts!ProcedureA. Open the following website:BioManBiology.Nodate.BiologyGamesandVirtualLabs:Evolutionhttp://biomanbio.com/GamesandLabs/EvoClassGames/aaevo.htmlB. Click where it says Press Spacebar or Click Here to Continue! And click again tocontinue.C. Read over the instructions carefully, paying particular attention to the controls. Noticethat as you successfully shoot the correct answer, you will need to reload.D. Click again where it says Press Spacebar or Click Here to Continue!E. Click on Mechanisms and begin.a. A statement will be shown at the bottom of the screen.b. Use the arrow keys to move to the correct term and use the space to shoot itUpdated October 2013down. Remember to reload!c. Keep playing until you are told You have succeeded here earthling! But can yousave the rest of your planet? Start over if you fail.F. Record your % correct and score in Table 3 below when you are done. Feel free torepeat to improve your score if you would like.G. Reload the page to start over or click on the link above to return to the start page.H. Click where it says Press Spacebar or Click Here to Continue! And click again tocontinue.I. Review the instructions and click again where it says Press Spacebar or Click Here toContinue!J. Click on Mechanisms 2 and begin.a. As before, a statement will be shown at the bottom of the screen.b. Use the arrow keys to move to the correct term and use the space to shoot itdown. Remember to reload!c. Keep playing until you are told You have succeeded here earthling! But can yousave the rest of your planet? Start over if you fail.K. Record your % correct and score in Table 3 below when you are done. Feel free torepeat to improve your score if you would like.L. Answer the questions that follow.Table 3. Results (2 pts)% CorrectScoreMechanisms1001003Mechanisms 21001006Questions1. Match the following statements with the correct term (5 pts)a. Mutationb. Genetic driftc. Gene flowUpdated October 2013f. Bottleneckg. Founder effecth. Immigrationd. Natural selectione. Non-random matingi. Emigrationj. Speciation____ Type of genetic drift that occurs when a new colony is established, that bychance is genetically different than the original population.____Can result in evolution by acting on favorable traits.____ Only male lions with large, thick manes are able to breed.____Reproductive isolation of two populations of penguins can result in this.____ The loss or gain of alleles from a population by the movement of individuals intoor out of the population.____ Movement of individuals into a population, bringing with them new alleles.________Random events that cause changes in gene frequencies.Type of genetic drift in which there is a drastic reduction in population size anda change in allele frequencies.____ The ultimate source of new alleles and traits that natural selection can act on.____When individuals leave a population, taking alleles along with them.Week 7 Experiment Grading RubricComponentExperiment 7Exercise 1Experiment 7Exercise 2Experiment 7Exercise 3ExpectationPointsCollection of data and generation of a line graph correctlylabeled (Table 1 and graph of data).5 ptsDemonstrates an understanding of evolutionary change withoutnatural selection (Questions 1-4).8 ptsCollection of data and generation of a line graph correctlylabeled (Table 2 and graph of data).5 ptsDemonstrates an understanding of evolutionary change withnatural selection (Questions 1-5).8 ptsSuccess at Angry Aliens and an understanding of themechanisms of evolutionary change (Table 3).2 ptsDemonstrates an understanding of the various mechanisms ofevolutionary change (Question 1).

 

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