May 28, 2012

Natural Selection In Giraffes

I chose to model the evolutionary process of natural selection and how it affected giraffes.  I chose to model it by showing the changes before and after of the giraffe due to the natural selection. I chose to represent it in this way because you can easily and clearly see the drastic change that occurred in the giraffe, from short neck to long neck. Natural selection though didn't make this change suddenly, the length of the giraffes necks increased in increments over time through evolution and eventually increased to the current long neck size. The reason for this evolutionary process as shown above in the picture is because the short neck giraffes couldn't reach the leaves in the trees and therefore couldn't survive. This evolution is selective because only the giraffes that had longer necks were able to successfully compete, and then be able to reproduce with other long neck giraffes, and thus producing offspring with more long necks, and fewer with short necks. This isn't random evolution because only the long neck giraffes would survive so they would be the only ones reproducing and making more long neck giraffes, because that is the favorable trait in their environment. The source of variation that lead to the evolution was that there were giraffes in the same area that had shorter and longer necks, and the ones with longer necks were able to reach the trees to eat and survive, so the ones with the shorter necks couldn't compete as well and therefore wouldn't reproduce to create more short necks.

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