Percipitation Levels and the Affects to Beak Size Essay

915 WordsFeb 11, 20114 Pages
Precipitation Levels and the Affects to Beak Size Dixie Woodard BIO/101 November 22, 2010 Alison Barrett Precipitation Levels and the Affects to Beak Size The experiment demonstrates the affect of precipitation levels to the beak size of finches on Darwin Island and Wallace Island. The levels of rainfall not only affect the beak sizes of the finches but also the population over time. The experiments were conducted over a period of three hundred years. The parameters remained constant over the three hundred year span to determine the effect of more or less precipitation on the food sources for the finches. The level of rainfall controls the types of seeds the birds eat. More rainfall creates smaller, softer seeds. Less…show more content…
The size of Wallace Island was increased from 0.5 km to 1.0 km. and no change to the precipitation level. Darwin Island size remained the same at 0.5 km but the level of precipitation was increased from 20.0 cm to 50.0 cm. The experiment was conducted over a three hundred year span with the same parameters to measure the affects to beak size over time. The last experiment parameter changes were also to the island size and precipitation levels. Darwin and Wallace Island size were increased from 0.5 km to 1.0 km. However, the precipitation levels were changed to 40.0 cm from 20.0 cm on Darwin Island and reduced on Wallace Island from 20.0 cm to 10.0 cm. This experiment provided the most drastic results in beak size over a three hundred year span. The populations of the birds were almost the same number after two hundred years. But, the beak sizes were markedly dissimilar. According to the data, in the year 2210, the population of both islands had a difference of only 19 birds. However, the beak size for the Darwin Island finches was 19.93 mm and the Wallace Island finches had beak sizes of 24.29 mm. [pic] Results from first run of data. [pic] Results from second run of data. [pic] Results from third run of data. The data in the charts provides information to support the theory that less rainfall will
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