Voyages of Discovery and Understanding 7 December 2002

Winter term

Biogeography exam

Answer four (4) of the following six questions. Your responses are due at the beginning of class on 14 December ‘02. Your responses should be typed, double-spaced with 1" margins. You can use figures, graphs and diagrams that you draw yourself. Limit your responses to a maximum of two pages.

1. Discuss the factors that produce global patterns in solar radiation, air circulation, and ocean currents. Describe how these climatological factors interact with landforms to produce the patterns of vegetation that we observe. Include the effects of mountains. Use examples, including places that we have discussed in class.

2.  Discuss plate tectonics (continental drift), and relate tectonics to orogeny (mountain-building) and biogeographic patterns in the distributions of organisms. Use examples, including places that we have discussed in class.

3. What are the principal biological events or processes that produce and biogeographic patterns in the distributions of organisms? What are "disjunct" distributions, and what hypotheses have been proposed to explain them? Comment on some mechanisms of dispersal in plants and animals, including their relative effectiveness. Discuss barriers to dispersal, and their consequences. Use examples, including places that we have discussed in class.

4. The Janzen-Connell model is a hypothesis that attempts to explain why tropical forests are so diverse. Explain the model. What assumptions does it make? Discuss any evidence that tends to support or refute this idea.

5. Islands vary widely in the total number of species that live on them. The Theory of Island Biogeography attempts to explain this variation. Discuss the basic elements of this theory, including dispersal and extinction, and explain how these processes lead to different species numbers on different islands. Relate this to conservation of species on both real and "ecological islands."

6. Compare and contrast the biological diversity of the different regions we discussed in class (Pacific Northwest, China, Indonesia, Australia). Why are some regions more diverse than others? Consider climate, latitude, soils, topography and/or other relevant factors. What arguments can you make in favor of the conservation of biological diversity? Discuss endemism — what is it, what is its biogeographic significance, and what does it have to do with conservation?