EESB18H3 Lecture : Mass Extinction (near-verbatim)
22 Jan 2013
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Document Summary
Know the differences between asteroids, meteoroids and comet. Understand the physical processes associated with airbursts and meteorite impacts. Understand the possible causes of mass extinction. Know the evidence for the impact hypothesis that produced the mass extinction at the end of the cretaceous period. Know the likely physical, chemical and biological consequences of impact from a large asteroid or comet. Understand the risk of impact or airburst of extra-terrestrial impacts and objects. Sudden loss of large numbers of plants and animals relative to # of new species being added: extinction = not just an absolute destruction of all living organisms; it"s a relative net loss. Losing more than gaining new species mass extinction. Defines the boundaries of geologic periods or epochs: clearly see mass extinctions that relates to what was happening during that time. Usually involve rapid climate change, triggered by: plate tectonics. Moves habitats to different locations: volcanic activity. Volcanic ash reflect radiation, cooling earth: extraterrestrial impact.
