Darwin and Wallace Island Finch Evolution Lab Experiment

Evolution and Natural Selection have been a recurring focus of biology throughout the years. This Particular experiment is based on Charles Darwin’s observations of finches made in the Galapagos Islands. He noted that different neighboring islands in the Galapagos had distinctly different types of finches. He theorized that this was caused by natural selection, where the environment determined the characteristics of the species in it.

In the Evolution Lab Experiment, I looked at how beak size and population numbers for two hypothetical populations of finches on two different islands evolved in response to factors that I manipulated by changing environmental conditions. The specific environmental conditions that I chose to manipulate were the precipitation in the environment and the variance of the finches. However I only manipulated the precipitation and variance on Darwin Island and not on Wallace Island.

I thought that if Darwin Island finches had less variance and less precipitation than Wallace Island Finches, that Darwin Island finches would be unable to effectively adapt in order to easily consume the type of seed that was a result of the lesser amount of precipitation. MATERIALS The materials required for me to complete this experiment were my laptop and my University of Phoenix Student Website. Once I accessed the University of Phoenix Student Website, I was able to access the Evolution Lab, which is the final required material.

An optional material that I chose to use was a pen and paper to take notes. PROCEDURES In order for me to accurately test my hypothesis, I needed to first get to the Evolution Lab. Once I logged onto my University of Phoenix Student Website, I went to the classroom tab and clicked on Evolution Lab, which is found in week three. Once I pulled up the Evolution Lab window, I chose the button labeled “Change Inputs”. Once I arrived at the screen with the seven variables on the left and the pictures of the finches on the right, I clicked on the tab labeled “Variance”.

The next step is to change the Darwin Island Finch Variance to 0. 50. I did not change the Wallace Island Finch Variance. After the Variance was set, I clicked on the tab labeled “Precipitation”. I changed the precipitation on Darwin Island to 10 centimeters and left Wallace Island Precipitation at 20 Centimeters. Since I only changed two variables in an attempt to pinpoint the cause of the results, the next step was to click the tab labeled “Done”. After I chose whether I wanted to look at the results over 100, 200, or 300 years, I clicked the tab labeled “Run Experiment”.

At this point, I was ready to analyze the results and take notes if I needed to. Lastly, if I needed to extend the time the results were recorded, all I needed to do was click the tab labeled “Revise Expt. ”. Then I clicked the pull down tab and changed the range from 100 to 200 or 300. DATA DISCUSSION As seen in this experiment, when the Variance was lowered along with the Precipitation on Darwin Island, the population was on average, half of that of Wallace Island where the numbers were left in the default status.

I made the hypothesis that if I decreased the variance and precipitation on Darwin Island, that the finches there would be less able to adapt their beaks to accommodate the larger size of seeds and would eventually all die off. Since the graphs produced from the Evolution Lab program did not depict the species of finches on Darwin Island falling to zero, my hypothesis did not turn out to be correct. I believe that with the variance lowered to . 5 and not all the way to zero, the finches were still able to evolve, but not as rapidly as the finches on Wallace Island.

In addition, since only a small amount of evolution was necessary for the finches on Darwin Island to be able to consume the larger seeds produced from a decreased amount of rain; I believe they could have survived with an even smaller amount of variance. The reason I feel that a smaller amount of variance would have sufficed is that, not only did the finches in my experiment not go extinct, but they only remained below their initial population for the first fifty years after the parameters were put into place.

One aspect of the experiment that I feel could be improved upon is the lack of information on how many times a new generation was produced. I was wondering how many times the finches would have to produce offspring in order to observe evolution. I can see that it took the finches on Darwin Island fifty years to regain their initial population of 200, but I would like to know how many times in that fifty years new generations were produced so that I could connect rise in population with a number of generations so that I might be able to predict future evolution.

An additional way that the experiment could have been improved would if I had given the Wallace Island finches an increased number of variance and same amount of precipitation. This would have allowed me to not only see what would have happened when the finches had a higher likelihood of evolution to the decreased amount of rain and therefore a solidified cause for the resulting population, but it would have allowed me to analyze the reverse effect and possibly predict trends. CONCLUSION

Overall, I tested the effect of lowered variance and lowered precipitation of one population of finches while leaving another population of finches as the control group. I predicted that the finches with the lowered variance and lowered precipitation would become extinct. Even though my hypothesis was rejected at the end of the experiment, I learned that even with an increase in the size of their food as a result of lowered precipitation and a lowered ability to evolve, the finches on Darwin Island rebounded quite quickly.