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 Date: 11-11-10 Module: Evolutionary Genetics Exercise: Introduction for experimental design of //C. nemoralis// Studying snails, //Cepaea nemoralis//, can benefit our understanding of human just human? evolution because both species are affected by the same evolutionary processes, mainly natural selection, genetic drift and gene flow. However, studies on humans can be time-consuming, as both permission and ethical reasons reasons, or clearance/justification are needed to carry out the study, and may require expensive examination techniques when the phenotype is not clear or is affected by more than one gene this applies to snails too. Snails, on the other hand, can be collected and examined within a single day because they have an easily visible phenotype, namely the shell’s colouring and banding, and their size makes it easy to collect, identify, and examine some time after collection. The sampling methods will concentrate on discrete meta-populations explain term. Are they truly 'discrete' of //C. nemoralis// in a particular habitat. In this case a woodland and a grassland. The samples are to help us comprehend our findings by focusing on one habitat and comparing living snails with the same amount of dead ones. We hope to be able to understand if colour and banding are a product, or driver, what is the distinction? of selection pressures, genetic drift, or gene flow. Predation, luck, geography, and the ability to absorb solar rays for heat can all affect the frequency of particular phenotypes in living or dead snails in the habitat evidence? (citation?) also explain the logic of living/dead comparisons. These factors can work independently or in combination. By studying individual meta-populations in one type of habitat at a time, we hope to see if there is a pattern or consistency in colour and/or banding of living and dead snails vague. Explain more clearly. Aiming to collect at least 20 individuals whether living or dead per sight look up spelling. This should provide a sufficient sample size. We will try and keep the samples in each habitat relatively close to each other to try and avoid drawing conclusions which are actually the results of a founder event how would you know, what this the logic? . We will separate the sample collecting distances via paces, using one person to measure these distances to avoid unequal population separations. We aim to compare the adaptations how will you know what is an adaptation? of snails, in different habitats and to judge whether gene flow, genetic drift or selection is causing these morphological variances. If colour distribution and banding pattern was due to natural selection we would find that colour of snails’ shell would affect their survival. As all snails eventually die regardless their fitness, we will try to investigate the various causes of death (i.e. mortality due to predation) how? . If the results will show remember you are writing in the present about what you thought would happen in a experiment that has been done. You might write, 'If the results had shown' or 'were the results to have shown' that different populations in the same habitat have greater phenotypic variation without any standard repeated phenotype unclear. explain, it would be likely that the pattern is due to genetic drift. If the main cause was gene flow, we might find gradual phenotypic variation between individual meta-populations in each habitat. (446)

CONTRIBUTORS: Secretary: Jennifer Lee Giorgia Lombardi Kristine Vaivode Felicia Davies James Howell