EOSC 114 Lecture 7: Impacts from Space and Mass Extinction Events (Complete)
16 Aug 2017
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Document Summary
Lesson one: extinctions the great dying: the earth"s changing biosphere. A mass extinction is a crisis that affects life right across the planet from the deepest oceans to the highest mountains. Life has evolved, which has changed the character of the biosphere through time. The following 5 concepts are vital to the interpretation of geological record and the ancient biosphere they contained: the principle of superposition is a fundamental principle of the study of rock layers. By recording the sedimentary rocks and the fossils they contain, geologists in the late 1700s started to get the impression the. Today we have a time scale that divides the earth"s 4. 6 billion years into various time periods: mass extinction events: definitions and number. Extinction is the expected fate of species. Between 95-98% of all species would go extinct during this event. Both ocean and land based ecosystems were effected, and it was less than 1 million years in duration.
