Norman+Nemoralis+and+the+Mighty+Molluscs!


 * Alaina Morgan*
 * Tara Staunton
 * Conor Ferguson
 * Venny Prokopieva
 * Eleanor Matthews

__** What we are going to do: **__ We are going to do a horizontal transect of the field site. We will be sampling the grass sites and bush sites. We will take 3 samples in the bushes and 3 samples in the grass. This ensures that we have repeats at each site. To ensure that the populations are independent our sites will be a certain distance apart (20-30m), which could be measured by a preliminary survey of the site.This will confirm that there is minimal gene flow between the different populations. We will have standards within the group, which will be set before the task - to clarify the colouring and banding of the snails. We will also be taking our samples at the same elevation to eliminate one variable.



__** Weaknesses. **__ The weaknesses of our study are that we are not including the forest habitat in our samples. However, we only had 6 samples and we wanted to measure only 2 sites to allow us to do repeat samples. Another weakness is only having 6 samples as this is a small sample size. To overcome this, we could compare results with another group. This could be done by talking to another group to discuss our standards of sampling and ensure that they follow them. The data that they collect and the data that our group collects can be compounded together so that there is a larger sample size. This would be more effective if they had taken their samples at similar elevations as our group in order to continue eliminating variables.

__** Strengths: **__ A strength of our study is that we have controlled as many variables as we can, which means controlling the altitude of the sampling site. Also, our samples will all be independent of each other because they are more than the required distance away ( as measured in the preliminary survey.)

__** Drift VS Selection: **__ Selection influences the frequencies to a greater extent than genetic drift or gene flow, if according to our data, separate sites of the same kind of habitat exhibit similar (statistically significant) frequencies of the four phenotypes. E g all (or most) of the grass sites have the same colour snail. However, if phenotypic differences are caused by drift, then different sites will be independent of each other and the distribution could be more random, meaning that the same type of habitat might have different coloured snails.

__** Hypothesis: **__ That the frequency of one snail polymorphism will be higher within a certain habitat, suggesting that there has been selection.

__** Null Hypothesis: **__ If phenotypic frequencies are not under the influence of selection, but only genetic drift, sites of the same type of habitat will not exhibit similar phenotypic frequencies. Separates sites can have prevalent phenotypes or not, but the prevalences may differ between sites of the same type.