Evolution Lab: Finches and Natural Selection
Antonio Joseph O. dela Merced
Principles of Biology
Instructor: Matthew Scholten
Evolution Lab: Introduction
Evolution is a natural process in which animals adapt to their surroundings so that they may survive. There are many variables in an animal’s environment that influence its evolution. The purpose of this lab is to examine finches from the island of Darwin and the island of Wallace and how the island size, finches’ clutch size and the precipitation on both islands directly affect the finches’ beak size and population. I believe that a larger island size, larger clutch size and high precipitation will lead to a smaller beak size and larger population.
Evolution Lab: Materials
The materials of this lab will consist of a computer and the Evolution Lab on the University of Phoenix student portal.
Evolution Lab: Methods and Procedures
In this lab, we will take the number of clutch size, island size and precipitation on Wallace island and double it for Darwin Island. First we will start by choosing our inputs for our lab on by clicking on the “change inputs” button. Finches on both islands will start with a beak size of 15mm. Variance of beak size on both islands will be 1mm. Heritability of finches on both islands will be 0.50. The clutch size on Darwin Island will be set at 20 eggs while the clutch size on Wallace Island will be 10 eggs. Darwin Island will be 1 kilometer in size while Wallace Island will be 0.5 kilometer in size. The population size on both islands will be set at 300. Precipitation on Darwin Island will be 100 centimeters while the precipitation on Wallace Island will be 50 centimeters. As you can see, Darwin Island will be double what Wallace Island will be in clutch size, island size and precipitation. The time frame for this lab will be 100 years, which can be chosen at the bottom left hand corner of startup page.
This graph below shows the results of 100 years of beak size evolution. The red line represents Darwin Island and the blue line represents Wallace Island.
The graph below shows the results of 100 years of population for both islands. Darwin Island represents the red line while Wallace Island represents the blue line.
We will now look further in to the average beak size and population for both islands. Initially (1990), the average beak size for finches on Darwin Island was 14.92cm +/- 0.98cm. The average beak size after 100 years (2090) was 11.94cm +/- 1.07cm. Average beak size on Wallace Island was initially 14.96cm +/- 0.95cm (1990) but by 2090, it was 16.94cm +/- 1.1cm. The population of both islands fluctuated every year but Darwin Island fluctuated more drastically that Wallace Island. Darwin Island’s finch population grew one year but would drop substantially the next year only to rebound the following year. Wallace Island’s population also did the same thing but at a much smaller scale. I believe that the experiment yielded great results in the average beak size of both islands with the differences in the variables of island size, clutch size and precipitation. Differences in population levels can also be seen between the two islands with Darwin Island having a bigger population due to its bigger size than Wallace Island.
Evolution Lab: Conclusion
In conclusion, I have found that my hypothesis for this lab can be accepted as true. A larger island size, larger clutch size and higher precipitation will lead to a smaller beak size and larger population. We see in the data that was gathered that Darwin Island with double the clutch size, island size, and precipitation than Wallace Island, had a bigger finch population and smaller average finch beak size. I have also determined that the one of the factors I have used in my experiment directly reflects the influence of natural selection in the finches. With Darwin Island having 100 centimeters of...
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