Natural Selection and Darwin's Theory of Evolution (As proven in a Variation Lab)

Essay by HackerXHigh School, 11th gradeA+, April 2006

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Variation is the source of evolution. In this lab, we took a closer look the variations in two different species that are commonly known. A countless number of factors could have fostered the variations that we examined in this experiment. Most of the reasons for the variations that we see can be accounted for in the following categories: genetically based, environmentally based and sampling technique. Genetically based reasons for variation come from the very source of life itself, DNA.

Changes in DNA (genetic mutations) in a species derive variations within a certain species. For example, possibly a small change in an anchovies DNA sequence occurred as a result of an error in DNA replication and this change affected the length of the anchovy. This variation would have been fostered genetically, so the reason for this variation would fall under the genetically based category. Variations could have also been fostered due to environmental reasons.

Possibly, a predator might have come along that only ate the larger fish, therefore killing off all of the larger fish in the species. Countless other environmental factors could have influenced the amount of variation that we saw. Also, some of the variation may have arisen from our sampling technique. We had multiple classes measure the lengths of different samples of anchovies and peanuts, so possibly some classes may have measured them differently. This would have created variation in the data. As you can see in the above graphs, each species tended to have a bell curve in the measurements of their lengths. There tends to be a collection of average lengths towards the middle of the graph, with outlying smaller and larger lengths for each species. Why is it that in two completely different species, the same pattern for the length measurements is found in each...