Geologic History of Earth
Using the Museum of Paleontology website (University of California, 2014), I found six significant events listed when I clicked on “bookmarks” in the tutorial: formation of the Earth and Moon 4.6 billion years ago, the appearance of the earliest life 3.9 billion years ago, the appearance of the earliest land plants 420 million years ago, the largest mass extinction 248 million years ago, dinosaur extinction 65 million years ago, and early hominid (“Lucy”) appearance 4 million years ago.
In the Geologic Time Scale section of the Museum of Paleontology website (University of California, 2014), I found that images of cyanobacteria are included in the Archaean time period. Besides, I discovered that there are three Eras in the history of the Earth: Paleozoic, Mesozoic, and Cenozoic. The Eras’ representative organisms are the following: brachiopods, progymnosperms, and trilobites for Paleozoic Era; conifers, cycads, birds, and dinosaurs For Mesozoic Era; flowering plants, saber-toothed cats, megaloceroses, and mammoths For Cenozoic Era (University of California, 2014).
In the Sam Noble Museum Mass Extinctions website (Sam Noble Museum, 2017), five major mass extinction periods listed: End-Ordovician, Late Devonian, End-Permian, End-Triassic, and End-Cretaceous. The End-Ordovician extinction was caused by a major ice age. Species from trilobites, brachiopods, corals, crinoids, and graptolites groups disappeared. The Late Devonian extinction occurred due to the cooling of the global climate. In this extinction, stromatoporoids, brachiopods, and a lot of trilobites’ species disappeared. The End-Permian extinction was connected to the global climate warming caused by intense volcanic activity. During this extinction, trilobites and tabulate and rugose corals completely disappeared, as well as a lot of species of rhynchonelliform brachiopods, crinoids, shelled cephalopods, and snails.
In the End-Triassic extinction, a lot of species of marine invertebrate groups, including brachiopods, shelled cephalopods, sponges, and corals disappeared as well as a group of land-living phytosaurs. It is believed that the main cause of extinction was climate change. The vast continent Pangea began to break. As a result, the volcanic activity increased, and a major scale of carbon dioxide was introduced into the atmosphere which led to global warming.
In the End-Cretaceous extinction, non-avian dinosaurs, flying pterosaurs, mosasaurs, plesiosaurs, and ichthyosaurs as well as marine invertebrates, including ammonites and some cephalopods and bivalves disappeared. It is believed that the reason for this event is the Earth’s collision with an asteroid and the dust release to the atmosphere (Sam Noble Museum, 2017).
Global Climate Change
I discovered that human activities which include burning of fossil flues (coal and oil) are related to greenhouse gas production. These activities increase the rate at which carbon is returned to the atmosphere (Pearson education, n.d.a).
From the Greenhouse Gas Simulation (Pearson education, n.d.b), I learned that the relation between temperature and percent greenhouse gases amount is directly proportional (higher gases emission leads to a higher temperature), while the relation between the percentage of gases and ice is inversely proportional (higher gases emission leads to decrease of the ice area).
The current situation reminds me of the End-Permian extinction. It was stated that this extinction was caused by volcanic activity. Carbon dioxide released into the atmosphere during eruptions. Moreover, released lava heated carbon-reach rocks which also led to greenhouse gas production (Sam Noble Museum, 2017).
It could be stated that humans’ activities connected to coal and oil burning currently lead to greenhouse gases emission and global warming.
Drawing Conclusions
Based on the provided information, it could be concluded that the history of the Earth includes five mass extinctions. All of the extinctions are connected to global climate changes. Nowadays, human activities cause greenhouse gases emission which leads to climate warming and might result in the sixth extinction. The history of the Earth was estimated using the geologic time scale based on fossil records. Still, it is not entirely clear if humans’ activities are the main reason for climate change or this process is a part of the natural temperature fluctuation.
References
Pearson education. (n.d.a). The carbon cycle and global warming. Web.
Pearson education. (n.d.b). The greenhouse effect. Web.
Sam Noble Museum. (2017). Extinctions in the recent past and the present day. Web.
University of California, Berkeley, Museum of Paleontology. (n.d.). Geologic time. Web.