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Lab 1: Microbial Evolution Results and Discussion Report Instructions This is an individual assignment prepared by you. Any submitted work (in part or whole) that violates the Monash University policies on plagiarism will be subject to strict penalty. Markers will report all instances where they suspect plagiarism/collusion. Please be aware that the content contained in this document was not written by you, inclusion of any ideas presented here must be appropriately referenced. Learning Objectives Use of an experimental model to address concepts in evolutionary biology. Summarise experimental data using Microsoft Excel to graph data • Use of a spectrophotometer and stereo microscope for making observations of microbial growth patterns. Introduction Although we generally consider evolution to be a slow process, the 'speed of evolution' is more a factor of the generation time of the organisms you are studying. Bacteria are an ideal model for evolution; they have a short generation time (45 minutes in the case of Pseudomonas fluorescens), they are easy to grow in the laboratory, they are prone to genetic variation in a similar manner as higher order organisms and bacteria are haploid (meaning that genetic changes have an immediate effect on the phenotype of the cell). It is important to note that in contrast to some higher order organisms, bacteria reproduce via asexual reproduction (binary fission), so genetic variation in bacterial populations is achieved via spontaneous mutation and genetic transfer between cells (called horizontal gene transfer). In this lab, we are only concerned with genetic variation as a result of spontaneous mutation and the subsequent selection in favour of advantageous traits; we will not consider the influence of horizontal gene transfer as this is a topic of investigation in subsequent year levels. We will be using the aerobic bacillus Pseudomonas fluorescens as our model organism and will investigate the adaptation of this organism to different environments where the oxygen concentration varies. In the heterogeneous environment, the bacterial culture is left stagnant for 7 days which results in the generation to numerous microcosms (small environmental niches) with different concentrations of available oxygen. In the homogeneous environment, the bacterial culture has been incubated with regular agitation leading to an equal distribution of key nutrients such as oxygen. Your aim is to determine if there is a change in the bacterial population over time and discuss potential mechanisms that may support the bacteria in each environmental condition

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5. The ISA Babcock Company supplies poultry farmers with hens, advertising that a mature B300 Layer produces eggs with a mean weight of 60.7 grams. Suppose that egg weights follow a Normal model with standard deviation 3.1 grams. A local company claims that its chicken feed will help chickens produce larger eggs. So the farmer who bought her hens from the ISA Babcock Company fed her hens the new feed for 2 weeks. Then she randomly selected 30 hens and weighed all of their 174 eggs produced the following week, finding a mean of 62.3 grams with a standard deviation of 2.4 grams. Is there strong evidence to support the feed company's claim? A) 1-population proportion hypothesis test B) 2-population mean hypothesis test C) 2-population proportion hypothesis test D) Matched pairs hypothesis test E) 1-population mean confidence interval F) 1-population proportion confidence interval G) 2-population mean confidence interval H) 2-population proportion confidence interval 1) Matched pairs confidence interval J) None of the above 26. It occurred to the farmer that the difference in weight of the eggs might have been due to other factors, like weather changes, etc., rather than the new food. So she ran another experiment where she randomly selected 40 hens and tagged their legs. She fed these hens the old food for three weeks, keeping track of the weights of the eggs for the third week. From the other hens, she randomly selected 40 hens, fed them the new feed, and tracked the weights of their eggs during that same third week. Is there strong evidence to support the feed company's claim? A) 1-population proportion hypothesis test B) 2-population mean hypothesis test C) 2-population proportion hypothesis test D) Matched pairs hypothesis test E) 1-population mean confidence interval F) 1-population proportion confidence interval G) 2-population mean confidence interval H) 2-population proportion confidence interval 1) Matched pairs confidence interval J) None of the above

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