EARTHSC 2GG3 Chapter Notes - Chapter 18: Ordovician
29 Dec 2019
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None of the disasters we"ve studied so far result in the killing of an entire species or millions of species. There are times when many or most species have become extinct. Without stressful events, we would never evolve. Scientists think we are in a 6th major extinction (end. Ocean chemistry (related to changes in the atmosphere) Usually multiple causes which lead to an extinction. Different species become extinct at different times. Rocks at the bottom of the escarpment contain organisms which are extinct. Evidence for rapid climate change, sea level change and chemistry changes. Much of the continent is flooded due to melting of the glaciers. Glaciation comes right after a warm period. Warm shallow areas allowed organisms to flourish. Glacier arrival changed temperature and bottom water chemistry. Glaciers melt and then everything floods, temperatures change. Some organisms can deal with this and some cannot which led to a mass extinction.
