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Natural Selection Lab- PhET Simulation – Keyla Putrika Pre-Lab Questions 1. What variables can you influence in this lab? Environments, long/short teeth, long/short tail, fur color, genes. 2. Define what a genetic mutation is. How do genetic mutations happen? How often? Genetic mutation is what makes us difference, there are two types of genetic mutation; hereditary and somatic. We don’t know the exact time when it will happen, but we can be sure that It will last for a long term. 3. What do the terms fitness and adaptation mean? What is the difference between the two? Terms fitness is the ability for an organism to survive and reproduce in the environment, meanwhile adaptation is like natural selection, the inherited characteristic increases the organism’s chance or survival. The difference between them is fitness is the organisms that survive longer will also reproduce more, but adaptation is the one that have more beneficial characteristic will have higher chance of survival. 4. What selection factors might effect an animal population besides the ones used in this lab? Artificial selection or selective breeding. Designing The Experiment In this Lab you will be controlling the mutations and environment of a population of rabbits. Your will create four hypotheses and design an experiment to test each one. Your hypothesis will follow the format where you fill in the (...) with your own ideas and reasons. I hypothesize that (select a rabbit phenotype) rabbits will be (more/ less) likely to survive under (type of selective factor) within the (select type of environment) environment, because..... (explain how their trait will help them to survive or not) 1. I hypothesize that white fur rabbit will be more likely to survive under wolves within the arctic environment, because white rabbit can camouflage, and brown rabbit is more distinct compared to the white rabbit. Meanwhile, in equator environment, brown rabbit will have more chance to survive than white rabbit. 2. I hypothesize that long teeth rabbit will be more likely to survive under food within the equator environment, because long teeth rabbit can grab the food better, and short teeth rabbit can’t grab the food very well. 3. I hypothesize that long tail rabbit will be more likely to survive than short tail rabbit under wolves within the arctic environment, because long tail rabbit will be more visible to the wolves. ***You must make at least one hypothesis for each of the three different types of phenotype mutations*** For each experiment you must have a control (no mutation) and fill in the following chart Experiment and Hypothesis Pheno type Selective Factor CONTROL Group Initial Population at F3 CONTROL Group Final Population Experment Group Initial Population at F3 Experiment Group Final Population Conclusion/ Observation 1 Brown Fur wolves 18 white rabbit 110 white rabbit 13 white rabbit 5 brown rabbit 64 white rabbit 9 brown rabbit White rabbit is more dominant than the brown rabbit in the arctic environment; my hypothesize is right. 2 Teeth food 18 short teeth 54 short teeth 5 long teeth 13 short teeth 23 long teeth 8 short teeth Long teeth rabbit is more dominant than the short teeth rabbit under food within equator environment; my hypothesize is right. 3 Tail wolves 18 short tail 34 short tail 5 long tail 13 short tail 25 long tail 101 short tail Short tail rabbit is more dominant than the long tail rabbit under wolves within arctic environment; my hypothesize is wrong. • • • For each of the experiments, begin by adding a friend and a mutation. Wait until the F3 generation before adding the selective factor. After adding the selective factor let the simulation run for another 3 or 4 generations. Use the population numbers from the chart to get you numbers for the table, remember you can zoom in and out on the chart to get more accurate reads. Repeat for experiments 2, 3 and 4 Post-Lab Questions 1. Based upon your evidence from the simulation what conclusion are you able to make about each of the three different types of phenotypes in rabbits? Each rabbit have different beneficial characteristic in them, the differences make them special in their own environment and they will have higher chance of survival and keep producing offspring compare to the others. 2. What happens to animals that cannot compete as well with other animals in the wild? They will die; eaten by the predators. Or they will have to move to other environment. 3. Sometimes animals that are introduced into an area that they never lived in before, outcompete and endanger resident species, why do you think this happens? Because the species haven’t adapted to the new environment. 4. If only one species is considered the "fittest", why do we still have so many variations among species. Why do some birds have very long pointy beaks, while other birds have short flat beaks? Because each organisms have their own characteristic and are adapted to the environment they’re in or the food they eat. Birds have different beaks because they are adapting to the food they usually eat. And if all organisms are the same, it means that if an individual gets sick, the rest of them will get it too and it can leads to extinction. 5. How do you think diseases can affect natural selection? If an individual is immune to a disease, it means that individual will survive and keep producing, meanwhile the ones that are not immune will die. 6. How does this simulation mimic natural selection? In what ways does this simulation fail to represent the process of natural selection? The simulation shows us that there are characteristics, environment, and selective factors, which all exist in real life natural selection. But, the amount of organisms and the time they adapted is not the same in real life, which kind of fail to represents the process of natural selection. Extension- Changing the Dominance and Recessive Alleles Take one of the experiments from the lab. Recreate the same experiment, EXCEPT when you add the mutation EDIT THE GENES by switching the dominant and recessive allele for that trait. Make a hypothesis, fill in the chart again and compare the results to your initial experiment. Experiment and Hypothesis Pheno type Selective Factor CONTROL Group Initial Population at F3 CONTROL Group Final Population Experment Group Initial Population at F3 Experiment Group Final Population Conclusion/ Observation I hypothesize that dominance white fur will less likely to survive under wolves within equator environment, because white fur rabbit will be easier to find than brown fur rabbit. White fur rabbit dominant. Wolves 3 brown rabbit 11 white rabbit 31 brown rabbit 5 white rabbit 1 brown rabbit 17 white rabbit 0 brown rabbit 1 white rabbit The brown rabbit population extinct and only 1 white rabbit exist. 1. Did switching the alleles for dominant and recessive have any impact on the population of rabbits? If so Why? In nothing changed Why not? Yes, switching the alleles impact the population. Brown rabbit has the dominant allele, which makes them have higher chance to have offspring with its fur color. In the end, the brown rabbit’s population increases, as the white rabbit slowly fades away. 2. Two parent rabbits are both heterozygous for the trait. Create Punnet squares for the original experiment and the new experiment (with the changed alleles). What are the phenotype ratios of the Punnet squares? Does this evidence support your finding? and how? It does support my hypothesize because the dominant allele will produce more offspring and eventually dominate the environment. original new ww WW (brown) (white) Ww (white) Brown : White Brown : White 3:1 1:3 Ww (white) 3. If this new experiment were to run longer would the end result be the same or different from the original experiment? It’s going to be different, because in the end of the new experiment, there’s only 1 white rabbit left, and if there’s a predator, the white rabbit will get eaten and the rabbit population will extinct. Extension- Working with Pedigrees- Switch from the population chart to the pedigree chart Begin by adding a friend and a mutation. Wait until the F5 generation. Copy the Pedigree for two rabbits (described below) using the key. Assume that male rabbits are on the left and female rabbits are on the right. WW ww (brown) (white) Ww Ww (brown) (brown) Find these two rabbits, make sure they have at least four generations: 1. Select a rabbit that has the mutation. 2. Select a rabbit without the mutation but with parents or grandparent with the mutation. Answer the following questions: 1. How could using a pedigree be helpful? Because it shows the rabbits’ family and incest. 2. What does it mean to have a yellow triangle above the rabbit? It means that rabbit is a mutation 3. What does it mean when a rabbit has a red X over it? It means that rabbit is already dead. 4. How accurate are the pedigrees used in this lab? Did each couple only have one baby? It’s accurate because the pedigree shows which rabbit has the mutation and which rabbit is already dead. Yes, each couple only have one baby.