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Nicole Murri Anthropology 1020 Natural Selection Lab Report Introduction When Charles Darwin reached the Galapagos Island during his five year trip on the HMS Beagle, he had noticed something specific about the finches of the island. From there he had examined the fourteen different species that derived from a common ancestor. Darwin later wrote about what he had learned from a specific bird, “The most curious fact is the perfect gradation in the size of the beaks of the different species of Geospiza... Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might fancy that, from an original paucity of birds in this archipelago, one species has been taken and modified for different ends.” (Grant, Rosemary & Grant, Peter) Information had shown that morphology of the beak comes from the factors of natural selection from the variation in food type, the availability of food, and the competition for food supply. From observing certain birds it could be seen that birds that crush hard seeds from the base of their beaks tend to have short, wide, and deep beaks. Birds that crush at the base and probe tend to have longer, narrower and shallower beak type. From their research it can be moved to the focus on cracking ability of a bird based on bite force and muscle placement. (Soons, Joris) From these observations brought numerous hypotheses and tests to prove why and how they have adapted. From our natural Selection Lab were able to simulate the possibilities of beak types and how they may be affected and adapted due to food source and other factors. Before the Natural Selection Lab, I had hypothesized from the list of beaks and the beak that I had had, the small hair clip, that the small hairclips would do better than the large hair clips. From what I could see from my hair clip, the legs were close together and I believed that they would be able to pick up a sunflower seed with ease. From seeing the large hair clips I believed that there was a large gap between each leg and it would allow the sunflower seed to fall between the gaps, making it much 1 harder to collect a large amount of seeds. From this observation I had concluded that small hair clips would do better than large hair clips. Materials and Methods For our experiment we used numerous tools to allow a number of possibilities. There were thirty-five small, plastic cups, five chopsticks, five large hair clips, five tweezers, five small hair clips, five binder clips, five chip clips, and eventually one tong. This experiment required thirty-five different students. It also required a bag of sunflower seeds and appropriate tools to record the results each round, and that includes a timer to keep track of the time for each round. In order to reenact this lab, first the instructor should hand out small paper cups to ever individual in the classroom. From there they must hand out the first five “beak” types, which were chopsticks. Next the instructor mush hand out five clothes pins, five large hair clips, five tweezers, five small hair clips, five binder clips, five chip clips. Each individual should have one cup and one of the seven different “beaks.” Next, the instructor will scatter a handful of sunflower seeds on all of the desks. The instructor will set sixty seconds on a timer and each student must attempt to pick up as many sunflower seeds with their beak as possible and put it in their cup, if a student manages to pick up all of their sunflower seeds they are allowed to move over to another desk and pick up other’s sunflower seeds. This is meant to replicate how much food a bird can eat with their variation of beak. After the round the instructor will ask how many sunflower seeds each student collected. The three students with the most will stand up and the three students with the least will also stand up. Those with the least will give up there beak type and will be given a new beak that it the same as one of those that had the most sunflower seeds. This is meant to replicate that the favorable variations in beaks will fluctuate and those with least favorable variations might decrease. During the beginning of the second round a new beak type will be added, the tong, this was to show that new mutations can come and they may be favorable or unfavorable. Each round continues with sixty seconds and continues the same way until the end. Our lab ended at 2 the fifth round, after each round we counted how many beaks remained of each type and wrote it down on the white board. Results From our results we can conclude that the chopsticks decreased from the beginning to the end. Clothes pins decreased from beginning to end. Large hair clips increased from beginning to end. Tweezers increased from beginning to end. Small hairclips remained constant until the last round and then decreased. Binder clips decreased from the beginning to the end. Chip clips increased from beginning to end. Tongs remained constant from beginning until the end. Overall, the three best “beak” types were large hair clips, tweezers, and chip clips. The three that decreased the most were binder clips, chopsticks, and clothes pins. However, the one beak type that more than doubled itself was tweezers. It went from five to twelve through five rounds. This can conclude that the tweezer beak type is the most favorable. From the graph and table on page six, the data demonstrates this information. Conclusion From the concluding information I can no longer support my initial hypothesis. Small hair clips stayed at a constant rate and decreased by one during the final round. Even though this shows that small hair clips could do well without comparison to others, it does show a risk of decreasing over a long period of time. In comparison to the large hair clips, they were able to stay constant for a small period of time but eventually slowly grow, this shows that large hairclips do better in comparison to the progress of small hair clips. However there are possible outside errors that could impact the results of the data. Each individual has a different method they used for picking up sunflower seeds, some are much faster and more skilled, and this affects how many sunflower seeds they will pick up. That may or may not have an effect on the numbers and has nothing to do with the actually clip. In addition, there were only five rounds, over other rounds the numbers could have changed in opposite directions, 3 or others could possibly get weak or hurt from their beak, which will affect the results. If this experiment were replicated by a whole other group of students the results could possibly be completely different. You have to take into consideration of tools, methods, time, preference, skill, and many other factors. Because of these factors, if this experiment were replicated by other researcher I cannot say that my results will be the same, and I cannot prove that my results are valid due to outside factors. Discussion The theory of evolution by natural selection comes from the idea of Charles Darwin and Wallace. It is the idea that genetics change in the number of specific traits in populations. With this there are four underlying assumptions. First, that there are natural biological variations occurring in nature. Second, that there is inheritance. Third, there is competition. Fourth, those individuals with favorable variations are more likely to survive and have more offspring, with this comes differential reproductive success. This activity stimulated the theory of evolution by natural selection because it demonstrated all of the four underlying assumptions. It showed that there were natural variations from the eight different beak types. From the loss of beak types and gaining of beak types of each round it was meant to demonstrate the passing on of traits from one bird to another and show the loss of bird type when it didn’t get enough food, which ties in with competition for food and reproduction. The lab showed that tweezers were growing in numbers and changing the population of bird to the more favorable characteristic. The frequency of tweezer beak type grew over the five rounds. There is beak variation in birds, some are favorable, some are not, but tweezer beak type was a favorable variation. This showed that tweezer beak type is passed on from parent to offspring. In every generation there are more birds than can survive, however; birds with tweezer beaks are more likely to survive and have more offspring. 4 Works Cited: Grant, Rosemary B., and Peter R. Grant. “BioScience.” What Darwin’s Finches Can Teach Us about the Evolutionary Origin and Regulation of Biodiversity. Oxford Journals, n.d. Web. 06 Feb. 2016 Soons, Joris, Anthony Herrel, Annelies Genbrugge, Peter Aerts, Jeffrey Podos, Dominique Adriaens, Yoni De Witte, Patric Jacobs, and Joris Dirckx. “Mechanical Stress, Fracture Risk and Beak Evolution in Darwin’s Ground Finches (Geospiza).” Philosophical Transactions of the Royal Society B: Biological Sciences. The Royal Society, 12 Apr. 2010. Web. 06 Feb. 2016. 5 Beak Type: Chopsticks Clothes Pins Large Hair Clips Tweezers Small Hair Clips Binder Clips Chip Clips Tongs Total: Natural Selection Lab Data Table Begin R1 R2 R3 5 5 4 3 5 4 4 2 5 5 6 7 R4 2 2 7 R5 2 2 7 5 5 7 5 8 5 10 5 11 5 12 4 5 4 4 4 34 34 2 5 1 35 2 5 1 35 2 5 1 35 2 5 1 35 14 \ Natural Selection Lab Graph 12 10 Chipsticks 8 Clothes Pins Large Hair Clips 6 Tweezers 4 Small Hair Clips Binder Clips 2 Chip Clips Tongs 0 Beginning 6 R1 R2 R3 R4 R5