Natural and Sexual Selection of Vestigial and Wild Type Drosophila melanogaster Abstract
In this experiment, vestigial flies as well as wild type flies were used to create some diversity as well as test one of our hypotheses. Our hypotheses are as follows; 1) The wild type flies will have a greater relative fitness compared to the vestigial flies based on only sexual selection. The wild type has a relative fitness of 1 since it has fully functional wings. Vestigial Winged flies are not as sexually appealing since their wings are not functional and the wing movement is a vital part of their mating ritual. 2) The vestigial fly will have a greater relative fitness when considering both sexual and natural selection. With the presence of natural selection (fly paper hanging from top of cage) posing a larger threat to the wild flies b/c they can fly better, this will allow vestigial flies to prosper better. To set up this experiment, two twenty-five gallon aquariums, 3 petri-dishes, 200 flies, rotten bananas, and yeast were used. It was decided that there would be 80 vestigial flies and 20 wild type flies to total to an initial population of 100 drosophila. In the sexual selection circumstance, the vestigial drosophila’s carrying capacity is somewhere around 80 individuals, which is consistent with the wild type drosophila’s carrying capacity in this circumstance (Figure 4). In the sexual and natural selection circumstance the wild type drosophila have a carrying capacity at approximately 100 individuals (Figure 5). As both of the p-values from each circumstances in our experiment are greater than 0.05, both hypotheses must be refuted. Introduction
This experiment focuses specifically on Drosophila melanogaster, also known as the common fruit fly (Lynch, M., et al. pp 645-663). For over 100 years scientists have been using them in experiments as they are referred to as a “model organism.” They were deemed a “model organism” since they are characterized as having a large reproductive capacity, a medium size, a short generation time, and are inexpensive to keep alive. Fruit flies only consume yeast growing on rotting fruit. Sixty-one percent of human genetic diseases have been found in fruit flies, they also share many similar genes with humans. The male fruit fly spends most of his time chasing after and singing to female flies with hopes of mating with her, they are successful about once a day (Stowe, K. 2008). The male fruit fly frequently sticks out one wing or the other which is accompanied by its vibration, producing a “love song” that can be recorded with specialized microphones (Hall, Jeffrey C., pp 1702-1714). To distinguish male drosophila from females, there must be a distinctive black spot on the distal end of their abdomen for it to be a male, the females do not have this black spot. In this experiment, vestigial flies as well as wild type flies were used to create some diversity as well as test one of our hypotheses. Vestigial flies do not have well functioning wings, however wild flies do have functioning wings. Within this experiment, degrees of natural selection, sexual selection, and a combination of both were tested on the two types of flies. Natural selection is survival of the fittest. Sexual selection is the ability of organisms to choose their mates depending on their species. Relative fitness is the ability of an organism and species to survive and produce fertile, successful offspring. Purpose of our experiment is to determine the effect of natural selection on two subspecies coexisting under similar circumstances. Our hypotheses are as follows; 1) the wild type flies will have a greater relative fitness compared to the vestigial flies based on only sexual selection. The wild type has a relative fitness of 1 since it has fully functional wings. Vestigial Winged flies are not as sexually appealing since their wings are not functional and the wing movement is a vital part of their...
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