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Diversity Brett Microbial Larose BSC 2011 Section #20 2/15/2009 By signing below, I guarantee that I am the sole author of this manuscript: Name: ____________________________________________________________ Date: ____________________ Introduction A microorganism, or a microbe, is a microscopic organism that is naked to the human eye. Prokaryotes, which make up the domains Archaea and Bacteria, are unicellular microbial organisms that are thought to have been the first organisms to inhabit the Earth. Because of their long evolutionary history, prokaryotic populations have been subject to natural selection for approximately 3.5 billion years. This enormous amount of time has allowed prokaryotes to become immensely diverse and adapted to their respective environments. (Campbell, 2008) Due to the extreme diversity present within prokaryotes, it is very difficult to distinguish between the different species. Because of the immense varieties present in Prokaryotes, scientists yearn to collect simple and uniform samples of diversity. Microbiologists have since then established a system in which culture mediumsliquids designed to support the growth of microorganismsare used to stimulate prokaryotic growth in agar plates. In this specific experiment, agar (a substance derived from seaweed) infused with different nutrients is used as the culture medium. (Lab Manual, 2008) In this experiment, microbial diversity that comes off a potato, cilantro, grape and strawberry after being washed will be tested. Petri plates already loaded with agar will be inoculated from different sources: sterile water, tap water, and tap water used to wash a vegetable or fruit. The plates will then be left alone for one By signing below, I guarantee that I am the sole author of this manuscript: Name: ______________________________________________________ Date: __________________________ week, where the microbes will grow. The next week, the colonies will be counted and the microbial density will be calculated. The main purpose of the experiment is to see which vegetable or fruit will have the most microbial diversity after being washed with tap water. Hypothesis Since the gelling agent of agar is composed of polysaccharides, and agar stimulates prokaryote growth, the strawberries will create the most microbial diversity, followed by the grape, the potato, and cilantro. Since strawberries are the sweetest containing the most sugarmore prokaryotes growth should be stimulated. Since cilantro has the least amount of sugar, less prokaryotes growth should be affected. Methods After obtaining five Petri plates, my lab partners and I labeled the plates with a Sharpie marker, without opening the plates. Plate 1 was labeled as the negative control (sterile water). Plate 2 was labeled as tap water only. Plates 3-5 were labeled potato respectively. Afterwards, a 1.0 mL pipette was obtained and 1.0 mL of sterile water was drawn into the pipette. The lid of the Petri dish (Plate 1) was then lifted just enough to squirt the water onto the agar, then closed immediately following. The Petri plate was gently then tilted and rotated until the water evenly coated all of the agar. By signing below, I guarantee that I am the sole author of this manuscript: Name: ______________________________________________________ Date: __________________________ Afterwards, a 1.0 mL pipette was obtained and 1.0 mL of tap water was drawn into the pipette. The lid of the Petri dish (Plate 2) was then lifted just enough to squirt the water onto the agar, then closed immediately following. The Petri plate was then gently tilted and rotated until the water evenly coated all of the agar. Five test tubes were then labeled: 1, 10. A large pipette was then used to transfer 10 mL of tap water from the paper cup into the test tube labeled with a 1. 9.0 mL of tap water was then transferred from the paper cup to each of the other sterile test tubes. The tube was then re-covered. My group and I then used forceps to transfer one piece of potato into test tube 1 containing 10 mL of tap water. The paper was then peeled fro the parafilm and the tube was sealed by stretching the clean side of the parafilm over the top. My lab partners then held their thumbs over the top and shook the tube vigorously for one minute. My lab partners and I then obtained a 1.0 mL pipette to transfer 1.0 mL of potato water to the test tube containing 9.0 mL of tap water. The tube was sealed with parafilm and mixed. My lab partners and I then obtained a 1.0 mL pipette to transfer 1.0 mL of potato water to the test tube containing 9.0 mL of tap water. The tube was sealed with parafilm and mixed. By signing below, I guarantee that I am the sole author of this manuscript: Name: ______________________________________________________ Date: __________________________ My lab partners and I then obtained a 1.0 mL pipette to transfer 1.0 mL of potato water to the test tube containing 9.0 mL of tap water. The tube was sealed with parafilm and mixed. My lab partners and I then obtained a 1.0 mL pipette to transfer 1.0 mL of potato water to the test tube containing 9.0 mL of tap water. The tube was sealed with parafilm and mixed. Afterwards, 1.0 mL of each of the last three test tubes was transferred to the matching Petri plate and then gently swirled so that the liquid covered the entire agar surface evenly, as before. A few pieces of tape were used to secure the lids to the dish bottoms. After 1 week elapsed, the data was able to be recorded. My lab partners and I took into account the different colony shapes and colors and their traits, and recorded the data. Data The results of the experiment indicated that the strawberries had the most microbial diversity. The cilantro had the least microbial diversity. Every group for the strawberries had a numerous amount of colonies. The grape colonies had the second highest number of colonies. The potato colonies had the third highest number of colonies. The cilantro had the least amount of colonies. By signing below, I guarantee that I am the sole author of this manuscript: Name: ______________________________________________________ Date: _________________________ ... View Full Document

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