As you have seen in the tutorial, we have gathered a lot of information about the organisms that lived before our time here on Earth. We have learned that many organisms no longer exist on our planet. We describe these organisms as extinct. From our fossil record, we have evidence of mass extinctions, during which huge numbers of organisms completely disappeared during a short period of time. In fact, it appears that mass extinctions have occurred several times in the earth’s history. Review the mass extinction(http://samnoblemuseum.ou.edu/understanding-extinction/mass-extinctions/) link to learn why this happens and how we know. Be sure to read the information found linked to each of these headings (located on the left-hand side of the website): End-Ordovician mass extinction Late Devonian mass extinction End-Permian mass extinction (the Great Dying) End-Triassic mass extinction End-Cretaceous mass extinction Now review the (http://samnoblemuseum.ou.edu/understanding-extinction/extinctions-in-the-recent-past-and-the-present-day/) that have occurred due to the effects of human activity. These Web sources, provided by the Sam Noble Museum(http://samnoblemuseum.ou.edu/understanding-extinction/mass-extinctions/), will also be components of your Case Assignment. 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? Read the article link on Recent Extinctions: Choose two of the recent extinctions(http://www.popularmechanics.com/science/animals/g201/recently-extinct-animals-list-470209/) listed on this link and explain why 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 the “Recent, Past and Present” section from Mass Extinctions(http://samnoblemuseum.ou.edu/understanding-extinction/extinctions-in-the-recent-past-and-the-present-day/). Also review the following link from the NASA website: https://climate.nasa.gov/causes/ Define greenhouse effect. Describe which gases are important to the greenhouse effect. What were listed as human activities related to greenhouse gas production from each link? How do humans contribute to both climate change and major extinction events? Some scientists think that human activities may be contributing to a sixth mass extinction event. What specific evidence do they site for this possible event? (you may need to conduct additional research to support your findings). Part III: Drawing Conclusions Now provide a summary that explains what conclusions you can make for yourself based on the evidence provided and what you now know about the geologic time scale of the history of the Earth. Assignment Expectations Organize this essay assignment using subtitles that summarize the topic from each question above. For example, to answer Question 1, use a descriptive subtitle like the following: Part I: Geologic History of the Earth/Major Events. Answer each question under the subtitle using complete sentences that relate back to the question. Be sure to use APA formatting throughout your essay with 1-inch margins, 12-point type, and double spacing throughout. Include a title page, introduction, answers to the questions with subtitles, and concluding paragraph. Remember to include in-text citations within the body of the essay referencing your resources (e.g., Murray, 2014). Also, be sure to include a reference section at the end of your assignment listing all required readings and any additional resources you used to complete your essay. A helpful guide to writing a quality essay can be found in Trident’s Student Guide to Writing a High-Quality Academic Paper. This guide also provides links to example essays written in APA format.