Mass Extinctions and Climate Change Essay

  • Length: 2 pages
  • Sources: 3
  • Subject: Environmental Science
  • Type: Essay
  • Paper: #32649800

Excerpt from Essay :

1. The bookmarks indicated the following six events:

· Formation of the earth and moon 4.6 billion years ago

· Earliest life, 3.9 billion years ago

· Early land plants 420 million years ago

· Largest mass extinction 248 million years ago

· Dinosaur extinction 65 million years ago

· "Lucy", early hominid, 4 million years ago



2. In the Archaean period, there are cyanobacteria and stromatites.



3. The three periods of time that are described as eras are the Paleozoic, the Mesozoic, and the Cenozoic.



4. There are five mass extinction events listed. They are:

End-Orcovician, where many types of ocean life became extinct including trilobites, brachiopods, and graptolites. The Late Devonian, stromatoporoids, brachiopods associated with reefs and more trilobites all became extinct, as coral systems suffered heavy losses. The End-Permian extinction saw some corals, trilobites, and types of brachiopods, orinoids and shelled cephalopods all became extinct at this time. The End-Triassic extinction hit many of those same groups, along with corals, and the land-dwelling phytosaurs. The End-Cretaceous killed off the non-avian dinosaurs, pterosaurs, mosasaurs, some groups of cephalopods and bivalves.



5. The End-Cretaceous appears to have been caused by an asteroid that hit the earth that created a dust cloud that circled the entire planet, greatly reducing the amount of sunlight reaching the earth's surface. The End-Triassic extinction was caused when Pangaea split, which created substantial volcanic activity, filling the atmosphere with carbon dioxide, leading to global warming.



Part II. Global Climate Change

6. The four greenhouse gases that are being measured by the simulation are carbon dioxide, water vapor, methane, and nitrous oxide.



7. The average temperature in the "Today" simulation is 59-60F. Adding clouds appears to do little, maybe up one degree. In 1750, the average temperature was around quite a bit lower, around 53-54F. The gas levels are as follows:



H20

CO2

CH4

N20



Present Day

70%

388ppm

1.843ppm

0.317ppm



1750

70%

280ppm

0.73 ppm

0.27ppm



Ice Age

?

180ppm

0.38ppm

0.215pm



During the ice age, the average temperature was a lot lower, bouncing around the 30sF.

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