Pepered Moth Lab

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The Affects of the Environment on Evolution as seen through the Natural Selection of Post Industrial Revolution Moths

The purpose of the lab was to determine if the changes in population of light coloured moths and melonic moths post industrial revolution was a result of natural selection through the melonic moths ability to avoid predation because of a better fitness. In order to determine if the changes in population density were attributed to natural selection one would look for a increase in population for each subsequent generation for the moth that possess the selective advantage. Such as for the pre industrial simulation the light moth’s population increase because of its ability to avoid predation because of camouflage. The method needed to complete this investigation would be placing fifteen melonic and fifteen light coloured moths on a sheet of paper then having an individual act as the predator attempting to remove as many moths as possible over a quantized time. The simulation would have to be completed for three trials representing each generation then repeated again utilizing a different coloured paper, the papers used should be white, intermediate (cream) and black. Observations were made and the results were that the species of moth which possessed a selective advantage was in fact better suited for the environment therefore able to avoid predation and experience thriving numbers. These results were standard for the light paper and intermediate paper although the black paper did not follow suit as a result of the melonic moths not in fact being fully dark. The experiment demonstrates that natural selection can be attributed to the diminishing number of light coloured moths following the industrial revolution and H.B.D Kettlewells hypothesis is correct. Introduction

In this investigation biologist H.B.D Kettlewell’s hypothesis pertaining to the environments effect on the evolution of the peppered moth of the 1800s was tested. In the early 1950's, H.B.D. Kettlewell, an English physician with an interest in butterfly and moth collecting, decided to study the unexplained color variations of the peppered moth. Kettlewell focused his study on a trend observed in Manchester England from 1845 to 1890 where the population of peppered mouths once made of gray coloured organisms inevitably was replaced with a darker almost black counterpart. Kettlewell hypothesized that a change in pollution found in industrial areas had provided the dark moths with a selective advantage over their peppered counterparts. This selective advantage, which increased the dark moth’s fitness, was the result of layers of soot altering the colour of barks of which the moths would reside. Therefore making the dark moths less susceptible to predation as a result of being better suited to the environment. Kettlewell focused his study on industrial Melanism, which is used to describe the adaption of population by the darkening of its individuals in response to pollution especially during the time of the industrial revolution. The industrial revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transport and technology effected the world through the introduction of coal powered machinery. The above noted adaption is directly linked to Charles Darwin’s Theory of Natural Selection. Natural Selection is the reproduction of organisms best suited, possessing a selective advantage, to thrive in their environment. A selective advantage is a genetic advantage of one organism over its competitors that causes it to be favoured in survival and reproduction rates over time. The purpose of this investigation is to determine if the extinction of light coloured (peppered moths) post industrial revolution was a result of natural selection due to the melonic moth’s selective advantage in soot-covered foliage. The hypothesis for this investigation is the appearance of...
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