Case Part I: Geologic History of Earth The first part of this assignment requires that you consider the history of extinction on our planet as explained in the links you viewed on the Home page. From the Museum of Paleontology tutorial on the Home page, answer the following questions. Use full sentences in paragraph form:

1. When you clicked on the “bookmarks,” which events were listed and in what order (there were six)?
2. In the Geologic Time Scale section, images of which organisms are included in the Archaean time period?
3. Which three periods of time are described as “Eras”? List the representative organisms included in the photos that appear when you click on each Era.
4. From the Sam Noble Museum Mass Extinctions How many major mass extinction periods are listed here? Follow the links from that page to learn more about each period. What caused each, and which major groups of species disappeared from each period?
5. Choose two of the recent extinctions listed on this link and explain how they occurred.

Case Part II: Global Climate Change Scientists have concerns that human activities are changing our environment at rapid rates that could result in a sixth mass extinction. Let’s examine the evidence: Review this tutorial on the carbon cycle and greenhouse gases.

1. What were listed as human activities related to greenhouse gas production? What does this do to the rate at which carbon is returned to the atmosphere?
2. Opponents of the theory of global climate change propose that extinctions are a normal part of our planet’s history and that the temperature of the planet has also historically fluctuated. Use the following Greenhouse Gas simulation. Begin by clicking on the “Simulation Controls” in the upper left-hand corner. Set the greenhouse gas level to the highest, check the boxes “view labels” and “view a possible consequence.” Use the arrow in the lower right-hand corner to watch the interactive graph, then select “run” on the simulation control window.
3. When you click on the “Graph” menu, what is the relationship between percent (%) of greenhouse gases and temperature? What is the relationship between temperature and ice? Which mass extinction from the Natural History Museum website in Part I does this remind you of?
4. What role does human activity play in the current global warming trend?

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