WALKINGSTICK PREDATION: BUSH ENVIRONMENT



Modeling Natural SelectionWalking Stick PredationGuiding Question: How and why do organisms change over time?Define Natural Selection: Describe natural selection and give at least one example of natural selection at work.BACKGROUND: The original scandal around Darwin’s ideas was not actually about the strongest surviving, leading to survival of the fittest. The radical notion was that there was not one ideal archetype for each species with all variant characteristics as deviant, but rather there exists a range or spectrum of variation that is normal and common. Evolution, in simplest terms, is a change or shift in gene frequencies. These changes occur because the environment interacts with natural variation within a population. Evolution on a small scale, generally within an observable period of time, is called Micro-evolution. House sparrows have adapted to the climate of North America, mosquitoes have evolved in response to global warming, and insects have evolved resistance to our pesticides. These are all examples of microevolution — evolution on a small scale (University of California Museum of Paleontology, Berkeley, 2011).Macroevolution encompasses the grandest trends and transformations in evolution, such as the origin of mammals and the radiation of flowering plants. Macro-evolutionary patterns are generally what we see when we look at the large-scale history of life. It is not necessarily easy to "see" macro-evolutionary history; there are no firsthand accounts to be read. Instead, we reconstruct the history of life using all available evidence: geology, fossils, and living organisms. Once we've figured out what evolutionary events have taken place, we try to figure out how they happened. Just as in microevolution, basic evolutionary mechanisms like mutation, migration, genetic drift, and natural selection are at work and can help explain many large-scale patterns in the history of life.In this lesson you will model a scenario in which microevolution might occur. You are a predator for walking sticks. This population of walking sticks lives in a bamboo forest. Unfortunately, urbanization is encroaching on the forest. Development occurs and the bamboo is essentially mowed down. You are unaffected though and continue to hunt walking sticks. Finally as the new environment progresses, smaller bushes and shrubbery start to grow. As a researcher, you will study how the genes in the population shift as the environment changes.PROCEDURES Go to the following website: the Class Login tabClass Username: PopeHSClass Password: popebiologyWALKINGSTICK BAMBOO ENVIRONMENT You will hover over the “walking stick” habitat. Select “find Insects in Three Environments”. You will then select the “30 clicks to eat insects” option. As the scenario explains, you will select the bamboo environment first. The 30-clicks hunting period is representative of 30 days, the time it takes for reproduction, egg laying, and hatching (the time for one generation to reproduce) in walking sticks.You will hunt for 5 reproductive generations. At the end, you will look at your results. Copy the results down on your chart.Unfortunately, the walking stick habitat has been destroyed. Thankfully, the walking sticks have survived.WALKINGSTICK WOOD CHIPS ENVIRONMENTYou will hunt for 5 reproductive generations in the Wood Chip Environment. NOTE: the parent generation in the new habitat started over with evenly dispersed variationAt the end, you will look at your results. Copy the results down on your chart.The habitat is recovering, and small bushes have started to grow in this habitat.WALKINGSTICK BUSHES ENVIRONMENTYou will hunt for 5 reproductive generations in the Wood Chip Environment. NOTE: the parent generation in the new habitat started over with evenly dispersed variationAt the end, you will look at your results. Copy the results down on your chart.Find Insects in Three EnvironmentsName: _________________________________Table 1. Genetic Shift in Walking Sticks after five reproductive cycles in a Bamboo Forest.Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green-Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET InitialEatenSurvivedInitialEatenSurvivedInitialEatenSurvivedInitial population161616Generation 1Generation 2Generation 3Generation 4Generation 5Table 2. Genetic Shift in Walking Sticks after five reproductive cycles in the destroyed habitat of Wood Chips.Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green-Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET InitialEatenSurvivedInitialEatenSurvivedInitialEatenSurvivedInitial population161616Generation 1Generation 2Generation 3Generation 4Generation 5Table 3. Genetic Shift in Walking Sticks after five reproductive cycles in the recovering habitat of Bushes.Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green-Brown INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET Green INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET INCLUDEPICTURE "" \* MERGEFORMATINET InitialEatenSurvivedInitialEatenSurvivedInitialEatenSurvivedInitial population161616Generation 1Generation 2Generation 3Generation 4Generation 5ANALYSIS - Graph results…Make one multi-line graph for each habitat. X-axis = Generations (1-5)Y-axis = Initial Population SizeGraph the initial population size for each generationOne line for each color variation (means 3 lines)3 graphs, one for each data tableANALYSIS QUESTIONS How does the genetic variation change over time for each habitat (bamboo, wood chips, & bushes)?Explain the results of the walking stick predation in terms of adaptations and ecological succession.Why is this an example of microevolution and not macroevolution?How does natural selection give evidence toward Darwin’s idea of Survival of the Fittest?Explain your current understanding of MICROEVOLUTION. Use as many of the vocabulary words as best you can with fidelity.NOTE: If you feel like you are still uncertain about microevolution, explore to the following web link: ................
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