Evolution and Natural Selection Lab Report

Rubric for Lab Report for Bunny Evolution and Natural Selection Instructions: In your research report, your lab group will synthesize your experimental results from the Bunny Natural Selection Lab (and even include general evolution and natural selection concepts from the Lizard Evolution Lab you think are important) into a report that discusses the purpose of the lab, the experimental design, results, and conclusions regarding how evolution happens through natural selection. Worth 40 points total. Introduction (10 points) Describe the broad concepts of natural selection and evolution and how it relates overall to species/ populations survival (3 points). Mention how variation is how natural selection “selects” those individuals better suited to an environment or gives an individual an advantage over another individual (2 points). Briefly describe how there was a bunny population you observed to see how it survived and potentially evolved under certain conditions (2 points). Explain that the purpose of the lab was for you to investigate the effects of selective pressures, mutations, and frequency of dominant and recessive traits on a bunny population in order to see how natural selection works and how evolution happens (3 points). (This section should be 7-10 sentences in length) Experimental Design (10 points) Describe all the categories of experiments done in a general way like a summary (3 points). Then, for each category, explain the overview of the experiment, not each step you did (7 points). It’s a one sentence summary of the purpose. Example: “A brown fur mutation and a selective pressure of wolves was added to the white bunny population in order to see whether brown fur increased survival of the population…” (This section should be 12-15 sentences in length) Results (10 points) Describe the results for each of your experiments (1 point for experiments #1-#8, 2 points for experiment #9, total 10 points). Use complete sentences. This section simply states the outcome not the reason why things happened. Include the population vs time graph with the legend for each experiment (screen shot and crop the pic so it’s just the graph with legend). Example: “In the selective pressures and mutation scenario, a mutation for long teeth in bunnies was introduced and resulted in bunnies with long teeth out-competing the regular teeth bunnies. Thus, the long teeth bunnies had higher survival…” (This section should be 9-12 sentences in length) Discussion and Conclusions (10 points) This is the section where you explain why you got the results you did for each experiment. This addresses each experiment separately (1/2 point for experiments #1-#8, 1 point for experiment #9, total 5 points). Then, compare the results of the experiments in a general way to explain how and/or whether selective pressures, mutations, and frequency of dominant and recessive traits help or not help a bunny population survive (5 points). Be sure to include how natural selection and evolution fit into the survival of populations like the bunnies. (This section should be 12-16 sentences in length) Bunny Natural Selection and Evolution Lab Worksheet ANSWERS BELOW The purpose of this lab is to observe a bunny population to see how it survives under certain conditions. You are investigating the effects of selective pressures, mutations, and frequency of dominant and recessive traits on a bunny population. There are nine experiments for you to complete that have been categorized. This information will be used to write a lab report. You can write directly onto this document. This is a team lab, so one person needs to submit it on the bunny assignment link. Use the link below to access the online simulation. It is your responsibility to find a computer that can run Java. It works most personal computers as well as school computers. https://phet.colorado.edu/en/simulation/legacy/natural-selection Without any selective pressures 1. Run the simulation as is without changing any factors. Click ADD FRIEND. Watch the generations of bunnies multiply. What happens to the bunny population when no selection factor is added? Why? (2 pts.) The bunnies multiply because they have no predators, there’s nothing to kill them and control their population, the bunnies ended up taking over the world With selective pressures 2. Reset and run the simulation again, click ADD FRIEND. Let it run for 3 generations (look at the bottom of the screen). Select FOOD as the selection factor. Explain why the population has a certain pattern (look at population vs time graph). What happens to the bunny population? Why? (2 pts.) Food was limited and bunnies were dying because of the limited resources but they were still reproducing to keep the population fluctuating. The adapted bunnies had an easier time eating the food the environment provided, that’s why the population was fluctuating because not all the bunnies were able to eat the food provided. With selective pressures and mutation 3. Reset and run the simulation, click ADD FRIEND. Let it run for 3 generations (look at the bottom of the screen). Then click on the mutation for LONG TEETH mutation and FOOD as the selection factor. How is this simulation different than in the previous simulation? Why? Use what you know of natural selection and evolution to explain. (2 pts.) The bunnies with the long teeth mutation survived more than the bunnies with the short teeth mutation. The long teeth mutation was more beneficial to the bunny population and as the generations went on more bunnies were coming out with long teeth. 4. Reset and run the simulation, click ADD FRIEND. Let it run for 3 generations (look at the bottom of the screen). Click on the mutation for BROWN FUR. Let it run for 2 generations. Then click on WOLVES as the selection factor. What happens to the WHITE bunnies and the BROWN bunnies in the population? Explain why. Inevitably, what happens to the WHITE bunnies? (2 pts.) The wolves came to eat most of the white bunnies while the brown bunnies survived. The brown bunnies survived because they were able to camouflage better in their environment. As the generations went on the bunny population had more brown bunnies than white bunnies. With selective pressures, mutation, and environmental change 5. Reset and re-run the same simulation in the previous question. This time after 5 generations with the WOLVES, select ARCTIC as the environment. What happens to the WHITE bunnies and BROWN bunnies? Why does this happen? Use what you know about natural selection and evolution to explain. (2 pts.) The wolves came to eat the brown bunnies because they stood out from their white environment. The brown bunny population went down drastically and eventually the brown bunny population disappeared. The frequency of a dominant and recessive trait in a population with selective pressures and mutation 6. Reset and run the simulation, click ADD FRIEND and add BROWN FUR mutation. Let it run for 3 generations and then click on WOLVES as the selection factor. Immediately, under EDIT GENES, select WHITE FUR DOMINANT. Explain what happens to the WHITE and BROWN bunnies (watch until the end). Why does this happen? (3 pts.) The white bunnies were getting eaten by the wolves easier because they stood out from their environment. The white bunnies adapted their fur and the brown bunnies were the ones surviving. Eventually the white bunny population was wiped out. The white bunny population would not reappear because the white dominant allele was gone from the genes of the bunnies. 7. Reset and run the simulation, click ADD FRIEND and add BROWN FUR mutation. Let it run for 3 generations and then click on WOLVES as the selection factor. Immediately, under EDIT GENES, select BROWN FUR DOMINANT. Explain what happens to the WHITE and BROWN bunnies. Why are the results of this simulation different than the previous simulation? (3 pts.) The brown bunnies had the advantage of not being eaten by the wolves but unlike the previous question, the white bunny population didn’t disappear completely, they disappeared for a while but then came back in a small amount. This is because the white fur gene was recessive and there wasn’t a big chance of the bunny coming out white so the white gene didn’t completely go away. Whereas when the white gene was dominant the bunny adapted to its environment and got rid of the dominant white gene for better chance of survival for the bunny population. When the bunnies that have the heterozygous gene mate with each other they will have the ability to make a white bunny, that’s why the white bunny population reappears. The more the heterozygous bunnies mate the bigger the chance the white bunnies have of reappearing. When the heterozygous bunnies mate there’s a 50% chance the offspring will be heterozygous and there’s a 25% chance the bunny will come out white. Mutation and selective pressure 8. Reset and run the simulation, click ADD FRIEND, and add LONG TAIL mutation. Immediately, under EDIT GENES, select SHORT TAIL DOMINANT. After 3 generations, select WOLVES as the selector factor. Let the simulation run until the end. What happened to the bunny population? (2 pts.) The short tail bunnies had the advantage because there was less chance of the wolves eating a bunny with a short tail. At the end of the simulation the population was wiped out. All the bunnies died because the bunnies were white and it was easy for the wolves to eat them all. 9. Reset and run the simulation, click ADD FRIEND add LONG TAIL mutation again. This time, immediately, under EDIT GENES, select LONG TAIL DOMINANT. After 3 generations, select WOLVES as the selector factor. Let it run until the end. What happened to the bunny population? What can you conclude about tail length and survival? Did the frequency of a DOMINANT trait matter? What does this mean about mutations? (2 pts.) In this simulation the bunnies lasted longer because some of the bunnies carried the heterozygous gene of a short tail so there was a chance of the bunnies coming out with a short tail, which would make it harder for the wolves to eat them. When the bunnies with the heterozygous gene repopulated with each other the more of a chance there was of the bunnies come out with a short tail, which made the bunny population last longer than when the bunnies had the homozygous dominant long tail trait. Eventually the bunny population was wiped out because the bunnies were white and they stood out from their environment. 1 2 3 4 5 6 7 8 9 …
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