This is an exam. You can use whatever books and notes you wish, but you may not discuss the midterm with anyone inside or outside the class.
If you have questions you should contact Sandra McBride directly.
Common questions and clarifications will be posted to the course newsgroup as they occur, so check the newsgroup regularly.
Print out and turn in the signed cover sheet with your midterm.
Part I. Natal dispersal distances of mammals. Natal dispersal distances are the distances that juvenile animals travel from their birthplace to their adult home. An assessment of the factors affecting dispersal distances is important for understanding population spread, recolonization, and gene flow-which are central issues for conservation of many vertebrate species. For example, an understanding of dispersal distances will help to identify which species in a community are vulnerable to the loss of connectedness of habitat.
To further the understanding of determinants of natal dispersal distances, researchers gathered data on body weight, diet type, and maximum natal dispersal distance for various animals. Data are taken from Sutherland, G.D., et al., 2000, "Scaling of natal dispersal distances in terrestrial birds and mammals," Conservation Ecology 4(1): 16. Shown here are the first 6 of 64 rows of data on mammals.
The paper can be found on the web here. You may refer to the Introduction and the "Data Collection" section of the Methods section. Reading beyond these sections is less likely to be useful. It is very long, and you may find it difficult to follow. You are not expected to repeat their analyses. The data we will use is taken from Appendix A2.
Use techniques from Chapters 7-11 to analyze the data to describe the distribution of maximum dispersal distance as a function of body mass and diet type. You will submit a one-page (maximum is one-page of text, 1 inch margins all around) writeup on the problem. You may put graphs on one separate page, and include a one-page appendix describing any calculations or extra graphs. The total number of pages you can submit is 3 pages.
Some specifics:
In your writeup, be sure to interpret the parameters of the model you select on the original scale of measurement. Use the model parameters to make comparisons between dispersal distances for the three diet types.
Note that our data does not include the Odocoileus virginianus, the white tail deer. Estimate the natal dispersal distance for a future observation of a white tail deer (a herbivore) with weight 86 kg and give a measure of uncertainty.
In the paper (paragraph above Figure 3), the authors make a decision to pool their data for omivores and herbivores and make conclusions about the differences in dispersal distances between carnivores and omnivores/herbivores. Make a statistical argument as to why this might be a good/bad idea.
Access the data for this problem.
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